I had never touched a floor furnace until recently. A company I do so subcontracting for took over an apartment complex with over 40, 4 unit buildings. I am amazed these things are still in use! I told them I didn’t know anything about them but they assumed since I do HVAC troubleshooting for them I could figure it out. Thanks for this old video!
Gotta love these simple units with the steady pilot light lit all the time. For about 2 cents a day in fuel, it keeps draft up the chimney and reduces bugs wasps and the moisture levels.
Sir, thank you so much for producing this highly educational video! You have no idea the trouble I have been having these past two weeks trying to fully grasp this simple concept of how a combination gas valve works! I've read the five or six pages in my college text book (Refrigeration & Air Conditioning Technology, Ninth Edition, by Eugene Silberstein) numerous times; but I just couldn't get a clear understanding of it until I watched this video!
The video is great, but it leaves out one important thing: the second solenoid, which was not shown and sits under the electric terminals, routes a small amount of pressurized gas to the bottom of the big diaphragm which effectively operates the main outlet valve (and also regulates the pressure). Gas pressure is used as the operating force for the main valve. This is important on "millivolt" versions of this valve, where a bigger 700 millivolt thermopile provides all the electricity to operate both solenoids. The thermopile would have to be very large to provide enough power to operate the main gas valve all by itself. 190055joe asked how 20 mv can operate the solenoid. The voltage does not "pull in" the solenoid, it just holds the solenoid in its fully-in position. That takes less current/voltage. The solenoid is "pulled in" when the Pilot button is pressed in by the person lighting the pilot.
Actually I did mention that it is pilot operated. I did not explain the operation of that part of the valve because this video is more about how the pilot safety works than how the gas is used to open the valve. Perhaps I should do one on how a pilot valve works. Thanks for the thoughts. GFM
That's the key part of the system that I was wondering about; this video cleared it up as the pull in current for any kind of useful solenoid would be far too high for a thermopile to drive, but since it's the human operator that supplies the force to pull it in, only a small amount of current is needed to maintain it above the drop out voltage of the solenoid coil. Your further description of a gas pressure operated relay completes the system, as the main gas actuation has to be done without human intervention.
Great video, thank you for taking the time to explain these type of gas valves. Although not used in modern furnaces, you still find these in gas operated hot water heaters.
Really enjoyed your presentation. I work with them all the time. Never took one apart due to possible leaks and you can't rebuild them. So I just throw them out and get replacement.
For a long time I have wantes to know how the gas valve operated in a device unattached to the mains electricity supply and no battery. Wikipedia was useless, only explaining how thermocouples worked which I knew already. The thermocouple-operated miniature solenoid came as a surprise as I would have thought that the thermocouple would not be able to operate a solenoid under its own power, but it does. A great explanation and a great series. Thank you.
This is a marvelous set of views of the inside. Thanks so much. Any additional explanation you can provide will be as useful I suspect. I direct people to your video.
Had the identical unit and this was a big help in helping me understand the operation!! You the man!!!!! Heater back up and running! Thankls a million!!!
GFM I think you left out an important part of the valve Solenoid. Thermostat is suppose to switch the heater on. Come across where not enough voltage on the micro thermostat and does not switch the valve on. Pilot is on but therm does not turn on valve.
I see this problem alot, on wall heaters were pilot is on and thermostat is not letting the gas flow. Checked at the thermostat, jumped and gas valve turns on just fine. I believe this is a problem with solenoid but I could be wrong. On a milivolt system
I guess I should rephrase my comment in a form of a question. When th pilot light is lit but the milivolt thermostat does not turn on gas valve. But thermostat is checked and working fine also on top of that wires being jumped at the Thermostat and then the Heater fires up just fine. I don't know what causes this problem. Is there 2 soleniod valves 1for the Thermopile and another for the main valve when switched at the Thermostat that turns on heater? Sorry for the dyslexic comments before this one.
That is awesome! I have worked with these valve's for years but did not want to take one apart because they can be pretty expensive, also time. Thanks!
I love your videos ever since I started in this field 7 years ago. I have a huge textbook which pairs nicely with your videos thanks so much for the teachings. im a maint. supervisor at an apartment complex and I recommend your videos to new techs to see the correct way of doing things and principles behind proper operation.
A while back I replaced the combination gas valve on our 1964 furnace. Thereafter, I noticed that the burners made a whistling sound (most likely from the gas orifices on the manifold). Eventually, using a water manometer, I dialed the manifold pressure down from 3.5" to 2.75", and the whistling was weaker. Fast forward to today, and using a digital manometer I fiddled with manifold gas pressure again. It would not go above 3.5", and would not go below about 2.66". At around 2.85" the whistling became quieter. Later today, while on our daily walk, my wife comments that the furnace always whistled!
Freaking brilliant explanation! I am wiring my millivolt gas fireplace to a WiFi module for Alexa to turn off/on cause the girlfriend is lazy. Needed to understand how to the valves worked and where I needed to set the transistor-controlled switch to give the 700mV to the main valve.
Thanks. That helps me understand why the regulator adjustment is so "insensitive", meaning that one screw rotation changes the pressure just a small amount. I guess the screw tensioning (or relaxing) that big weak spring centered on the diaphragm.
It is a gas pressure regulator for the manifold. It is a flame safety control (thermocouple flame safety). It is a manual shut off valve. It is an electrically operated solenoid valve. Hope that helps.
question. I took apart a thermostat (KKTB type model), for a convection oven (gas stove burners and electric oven). has baking (BA), broil (BR) and C(convection?). when i turn the knob for oven the heat element won't go on (I never used the oven after years and this is like the first time I used the oven function - so it can be considered first time). the oven at first came on very high temperature and then after wouldn't come on again. i took it apart to diagnose what the problem could be. the oven part is mostly hardwired, thermostat -> relays -> heat element (bottom and/or top). when i took off the thermostat the parts inside imploded, i put it back together but it seems that the 2 leads (+ and -) going to thermostat to control whether on or off connection is made are always connected state. the springs holding the bracket regardless of whether they are pressed or depressed, a connection (continuity) is always present. this is the only logical way i could find to assemble it back yet it doesn't seem to be correct. there is two brackets, one braket moves kind of up and down to connect to the leads. the other has a spring attached which goes back to the first bracket. then there is the second half of the box which has a round metal piece which is connected to the thermostat sensor, this goes on top of the first bracket. any idea about this type of thermostat?
Thank you, GFM. This is exactly what I needed. I've been working on an older ventless gas fireplace log in my home and couldn't figure out the regulator system. You are a good teacher. -- Bob
Great explanation. This type of valve is on a lot of builder drop-in fireplace units. I was getting mixed up about where to check the thermocouple voltage, now I understand why there is no terminal for it, it's that copper line into the solenoid. Thanks! Unfortunately I still don't know why my fireplace won't light... I got voltages that now check out after cleaning the thermopile -- when it initially failed the voltage was too low and they were fithy. But it still won't light. The troubleshooting things says one other test beside the thermocouple -- to check a the continuity from a safety magnet to ground -- which I can't find. I guess I'll have to replace the whole valve assembly.
Have old Warm Morning heater that I love. It has fan that is not used. It has the same on/off/pilot valve as pictured. Tan, push down for pilot turn to on when It has started. Easy to start. It periodically starts roaring when running, nothing consistent. From quiet to softish steady roar. I jump up, turn it to low and it often stops the roar and I quickly turn it back up and it works fine with roar gone. One time I had to turn off the gas at the pipe and right back on when just turning it down did not stop it. Since there is no motor running - just the gas coming through the lines... is it air coming through with the propane? Sound old tank is half full. Old regulator? Smell no leaks. Went through a spat of this happening around 4 am on cold mornings, but that seems to have quit. Out of the blue, it just did it again this (cold outside) evening. Help!!! No one seems to know what I am talking about. Thank for any help.
Great video! When I light my pilot the button doesn’t pop up quickly, rather it takes almost a minute to pop up high enough to move it to ON. Should I be concerned? 1977 Lennox (I have a video on my channel). There is no screw on the button or I would try to put a drop of oil where the screw goes. I don’t see a way to lube it...
Thanks so much for saving me the trouble of curious disassembly! I run an electronics lab and was curious as to how a ~30mV signal could hold a solenoid open without extra amplification circuitry. It's also nice to see the thermocouple solenoid come out so easily; a couple of additional pointers may have been helpful such as: can you simply take out the thermocouple solenoid while the gas is switched off? and can you generally purchase the thermocouple solenoids by themselves or must you purchase an entire combination valve?
I see how it works, now to find one showing how to adjust.. Have one without any electronics, from a Warm Morning space heater. Just bought it, yellow flame with mixture door open little more than 3/4 and weak pilot, hooked up to regulator for twin 20# tanks so that may be issue. But wanted to turn down flow as mixture is already open quite a ways, and turn up pilot a little.. Pilot goes out when it senses up to temp and flame goes out.. in a camper, have small door for airflow behind, this regulator and twin 20s serves a 30k BTU furnace and this is same BTU for max output, 9-30k, so thought would work, plan on switching to twin 100# or pig, just testing this used unit... There were 2 chrome caps and a door that swings open that says vent.. Looking online for model series to go off of, Honeywell so should still be able to find resources.. May check out your other vids to see if you deal with this style valve, but will keep looking to get this project done...
V5267F1007 was my valve, hunting for info now,, there is an adjustment on the hi-lo side under a cap hinged by 1 screw, then other side has 2 chrome caps, 1 with arrow and another says vent... so far would assume, the one under the chrome cover was pilot and the one under the sliding cover was flow control..
While pressing PILOT, eventually the solenoid keeps the pilot light valve open. So what then does the ON setting do? I'm trying to follow how the ON valve is first but the pilot light valve opens first ? Thanks
Emphasis on "hold". Except for certain limited applications, they will only hold a pilot valve open. Check out HVAC part suppliers on the internet looking for general replacement combination gas valve. GFM
Very thorough videos. I installed a Williams Montery (wall furnace) that I bought used. Didn't work until I replaced the thermopile. (I disassembled everything except the burners and control to clean the furnace.) Then the pilot ignited just fine but the burners did not light. The troubleshooting guide said to replace the gas valve (Robertshaw 710-502) which I did. The furnace now works very well. I took apart the old valve to see what failed. Everything looked good. When I tested the various terminals for continuity, I had good results. There is a wire from (what I think is) the burner control solenoid over to the terminal block. I get continuity there too. Should there be continuity when the valve is not connected to a source of electricity? From your articles, I get the feeling that this is a short, leading to what some call a "stuck valve." Is that what it could be? I couldn't pull out the soleniod, but based on your article for "chain control," I suspect that it the problem. Please comment.
Hi i have a pitco frialator fryer and it works fine but right before the temp starts to drop and wants to turn back on i smell gas than it turns on and the smell goes away and i thought that the combi valve is bad and replaced it but still have the same problem thanks for your videos.
Do the solenoid ever go bad... if so, can it be replaced .... I’m thinking... yes, no????????? ...I’m working on a Honeywell V810A1210 gas valve and the price brand new is $365.00 .... haven’t tested yet( the thermocouple for DCmv) ... just want to cover my bases, as you know it’s a old furnace.....you showed in your video, the seloniod... trying to look for this part.... can you help me please....
Williams Enclosed Hearth Heater model number 5001911. Pilot stays lit and main burner not firing up. Attempted to purge the air out of the line via the pilot tube but found minimal gas pressure in line. I heard no gas flow when opening the shut off valve to purge. Replaced integral twin stage regulator out by propane tank. Pressure is audible now and enough to purge line. Pilot light stays lit with blue flame Millivolt reading 30mV on thermocouple. Pilot knob is set to "ON" position. Problem: Turning the control valve to maximum, gas valve not opening. After shutting off pilot light, 180+ seconds later the "click" can be heard of solenoid disengaging from magnet in gas valve. Question: How can the solenoid open and there be no gas coming out to the burners? I'll cut and paste this same question on some of your other videos in hopes of getting it noticed.
Your system is, I believe, a thermopile system. The thermocouple holds open the pilot solenoid. The thermopile operates the main solenoid. I would guess the thermopile is weak or there are loose connections. Hope this helps. GFM
Thank for you this video, it was very informative. So if my flames on my propane deep fryer are not blue but yellow, which way should I turn the regulator? I was told they should be blue so they’re burning at a high enough temperature.
Turn the regulator Clockwise. There’s a reason why you’re not getting enough gas. A manometer should determine the w.c pressure. Should be 10-11 for LP and 3.5 for Natural gas.
This type valve operates on 24 vac. It can be used on most pilot safety applications. There is a millivolt type that operates only on millivolts usually for fireplaces. GFM
I can’t figure this out anywhere. I’m using a patio heater with the Shaw pilot knob. I have been looking for an explanation as to how the knob assembly works. It’s supposed to turn easily from off to pilot, then you must press down to light the pilot and then it will continue to the full on position. You can manually hold the pilot knob down and turn it to on to ignite the burner of the thermocouple doesn’t work (it shuts off once you stop pushing the knob). I was fiddling with the knob and it seems as though it got reversed mechanically? Now I can’t turn it to the off position without pushing down on the knob, but it will turn right from off to on without pressing down. (The opposite of the proper mechanism behavior) I was trying to learn how that mechanism works to fix it but that wasn’t discussed here (or anywhere) have you heard of this happening?
The safety valve operation is understood. When calling for heat, the large gas turn on is a little murky to understand. Electric from the same thermocouple?
If the valve is a millivolt controlled valve, it uses either the thermocouple or a thermopile to power main gas. The valve could also be powered from an outside power source. Either 24 volts or 120 volts. Hope this helps. GFM
grayfurnaceman Thank you. My 1962 model gas valve does not have any external power supply for the main valve operation. BUT we do have (2) two pilot lights. yes, two. one thru the gas valve for the primary valve and a SECOND pilot outside of the valve DIRECTLY to the pilot. Thank you once more, Only power comes from the therm..... whichever one we have.
Hi Mr. Gray: I have a ventless gas stove and I would like to convert the thermocouple to an external digital type. If it's possible, can you explain how that can be done?
I just installed a new pilot assembly W010-0790 ( it has both a thermocouple and thermopile ) on an old Napoleon fire place. It has a Robertshaw/Grayson gas valve. My problem is that my gas valve doesn't have a port to thread in the single copper wire from the thermocouple. I think my gas valve has a wire coming out of it that used to go to a separate thermocouple control ( probably held mercury ) that they no longer make. Can you tell me how I could get this hooked up ? Thanks in advance !! Jim ODonnell
Hi , I have one of these valves from my old 9,000 Btu camper furnace , Its a Honeywell version , could not find the model # ,, on miy valve the Pilot , on off knob will not turn anymore , its stuck in the Pilot position , I have taken it apart and cannot figure out why . Any ideas what could be stopping it from turning ?? It isa 1976 year model , thanks ..
It's not the voltage so much as the current. For a sensitive solenoid having a high number of turns of wire, a few milliamperes of current is all that's needed to move the core.
Do you use a sealant when putting the valve back together? I opened an old valve to a wall heater and freed up the stuck diaphragm. But didn't reuse because I didn't know if a sealant was needed?
Hi, i hear a clicking sound from gas valve when thermostat calls for heat. But the pilot is off. Does this clicking sound means that the gas valve is being energized and gas is going to burner even though the pilot is off? Thanks
The pilot safety valve is in series with the main gas valve. If either valve is closed, gas will not flow, either to the pilot or the main gas in virtually all gas valves. GFM
does this valve works the same as those dual intermittent pilot gas valves that use with intermittent spark ignition module? i was working on a york RTU with two gas valves. the terminals on the gas valve were TR, TH/TR, TH. the TH/TR was connected to PV of ignition module. the TH was connected to MV of the module. the TR was connected to ground. if i were to measure from TH/TR to TR i should get 24vac to open the pilot gas correct? and if measured from TH to TR i should get 24vac to open main valve for burner correct? so does this mean this gas valve has two coils? one for pilot gas and one for main burner? thank you.
If you are talking about combination gas valves, the manufacturers will not sell parts for them. There are rebuild kits for some regulators and manual valves but nothing I have seen for combination valves. If you know of some, I would like to see what you have found. GFM
Hey really appreciate the video! I was just wondering if you could explain what it means when the pilot nob does not spring back when released (in the pilot setting). For example, the pilot lights as normally during start up procedure, however once I let go of pressure on the knob, it does not spring back to the closed position. If I slightly tug on the nob it then shuts off.. In the owners manual for the unit, it specifically mentions if this happens then to shut it off immediately and call for a qualified service/maintenance provider. I have shut the unit off, just wondering if this is typical of a specific problem? I am sort of assuming it will need a whole new combination gas valve?
I have an old furnace. I tried to use this a few days ago. I turned the heater on via thermostat, and no warm air came out of the vent (but the fan was turning). I checked the pilot light and it was off. I re-lightened it (meaning gas was there). I turned the heater on again, with the same result. I checked the gas valve, TR and TH, 27V AC was there. Any suggestions?
I have a head scratcher. I smell gas when my boiler lights up and it takes longer (30sec) to ignite than before. Weil Mclain boiler, steam over gas system. Lit pilot. Has a robertshaw 7000erhc-s7c vale. Says it has slow opening feature for soft ignition. Any ideas before I replace the valve? Looks like the one in your vid. No complaints otherwise and everything looks visually good. Thanks for good vids.
I have a garage furnace with a White Rodgers combo valve. The TC is making over 25mV. I think I have a bad TC connection to the solenoid, open solenoid coil or stuck solenoid. Is it possible to test the pilot solenoid coil resistance with the TC disconnected? Black meter lead to valve body and red to the solenoid connection? Thanks if you can help
Thanks for the video. My problem is the flame goes out after I let go of the knob (after successful ignition), so I suppose is the thermocouple's fault.
Any advice on where the adjusting screw is for the pilot light flame on a Tiara II-B ? I replaced the Thermocouple Assy. with a new one from H+Home Tech. Tagged all wires, etc. and replaced as undone. Everything works, including the remote Themostat and control. However the pilot flame is 3" or 4"+ High and wide coming out of the pilot hood. Thx.
There is a pilot adjust slot head on top of the valve. Marked pilot. However, if the pilot is that high, you probably do not have an orifice installed in the pilot tube where it connects to the pilot assembly. GFM
This is exactly the system I have and even thought the thermal coupler was changed heater won’t stay ton for long time . I’ll hear a click and pilot is out. I can relight pilot light but when I turn to gas it goes out what to do ?
The reasons for that type of failure are numerous. Is the pilot covering the thermocouple at least 3/8"? Is there any draft hood spillage? Is the thermocouple tightened reasonably? GFM
The pilot solenoid is not replaceable on the gas valve. If the pilot safety was opening, it would not relight. I would be looking at the low voltage controls such as the thermostat or limit switch. GFM
Help! I have standing flame furnace with a 36c53-418 gas valve. The pilot keeps going out after 1-2 hours. I've changed thermocouple and high temp sensor. There is no flame roll-out. Earlier today I reignited the pilot, set gas valve to on, thermostat clicked and burners roared and fan forced air... the thermostat reached temp and burners shut down but noticed a flame sputter at base of burner tubes (where they meet perpendicular to gas tube going into furnace chamber) leading into furnace - pilot remained lit. I raised the temp on thermostat and furnace went on normally and again sputtering at base of tubes leading into furnace when thermostat reached temp - pilot still lit ( nice fanned flame hitting thermocouple). On the 3rd sequence the thermostat sent signal for heat and boom like a backfire the pilot went out and I can hear the gas hissing. Shut off furnace and gas line. Can this be a faulty gas valve 36c53-418. Cold n almost blowup in NJ
Anyone know of a good place for parts? I've got a 1978 furnace where the pilot light randomly goes out. Replaced the thermocouple a few times and then called the professional. When I told him in the street what I had he insisted it was a the gas valve and $100 later said I need a new furnace. I noticed my pilot light burning dirty while he tinkered. Hoping he was wrong with obsolete parts as the thing works great as long as it has a pilot
Great stuff GFM! Thanks fr putting forth the effort to help educate others!! Question... I have an older Empire Rh-65-1 space heater. This unit does not use any electricity. I had some problems that I think I've resolved. I've taken the burner and the main burner orifice out and cleaned them both to get rid of the loud resonating and yellow flame.. I have the primary air adjustment screw turned all the way in but still get some extinction popping and occasional resonating (but not nearly as bad as before cleaning). I notice a small yellow flame about 1"-1.5" at the main burner orifice when the pilot light is lit and no heat is being called for. The thermostat seems to be working fine as I can turn it up and it lights the main burner every time. But when the temp rises and the burner kicks off the flame is still at the orifice. I am concerned that the gas valve is bad? Empire sells a replacement valve R1624. I believe that is the Robertshaw 700-204? Its almost $300 through Walmart. Im not opposed to replacing it but don't want to spend the money if there's a cheaper fix. Any help here would be greatly appreciated!
The leaking by of the valve condemns it. I would not use the heater with that valve. The 700-204 is a hydraulic valve probably similar to the original. There could be some mounting issues if there is temp control rod mounted on the valve. GFM
the flow control adjustment that you shown in your video, is that for the pilot of the main gas flow control for the burner? I want to get a gas flow control valve that can have a wired thermostat that runs of a power pile. My existing heater is an old Coleman dual sided wall heater and it inconvenient to adjust the heat and a wired thermostat would solve that problem.
There are 2 flow controls on the gas valve. One is a set screw for the pilot adjustment and the other is a manifold pressure adjustment. Neither will work with a thermostat. However what you may have is a hydraulic valve that has a temp sensing bulb and an adjustment to change the gas flow to the burner. If it is a hydraulic valve there is no way to control except by adjusting the knob. GFM
@@grayfurnaceman I was planning on purchasing an entire Williams Monterey Plus gas valve, thermostat, stack senser, and pilot/power pile and removing my old gas valve to replace it with the Williams equipment. Thank you for your response!
What is the most common reason that a gas valve pilot will light but won't pass gas to keep burners lit? Have run into this a few times - normally we just replace the valve.
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10 years later and it is still a useful video.
This is one of the best videos explaining how a gas valve operates, period.
Thanks for the support.
GFM
Well done. It is always a pleasure listening to a dissertation from a tradesman who knows what he’s talking about.
Fantastic video, thank you very much. I always love knowing how things like this work.
I had never touched a floor furnace until recently. A company I do so subcontracting for took over an apartment complex with over 40, 4 unit buildings. I am amazed these things are still in use! I told them I didn’t know anything about them but they assumed since I do HVAC troubleshooting for them I could figure it out. Thanks for this old video!
Thanks for the great explanation of the combination valve. Nothing beats seeing things taken apart and explained.
Gotta love these simple units with the steady pilot light lit all the time. For about 2 cents a day in fuel, it keeps draft up the chimney and reduces bugs wasps and the moisture levels.
.60 a month.
Thank you for teaching . 🎉 there are not lot of people explaining this very well like you
Sir, thank you so much for producing this highly educational video! You have no idea the trouble I have been having these past two weeks trying to fully grasp this simple concept of how a combination gas valve works!
I've read the five or six pages in my college text book (Refrigeration & Air Conditioning Technology, Ninth Edition, by Eugene Silberstein) numerous times; but I just couldn't get a clear understanding of it until I watched this video!
Glad it helped.
GFM
The way you explained makes me easy to understand, thank you very much for the video.
Thank you for helping me understand how a gas valve work.
The video is great, but it leaves out one important thing: the second solenoid, which was not shown and sits under the electric terminals, routes a small amount of pressurized gas to the bottom of the big diaphragm which effectively operates the main outlet valve (and also regulates the pressure). Gas pressure is used as the operating force for the main valve. This is important on "millivolt" versions of this valve, where a bigger 700 millivolt thermopile provides all the electricity to operate both solenoids. The thermopile would have to be very large to provide enough power to operate the main gas valve all by itself.
190055joe asked how 20 mv can operate the solenoid. The voltage does not "pull in" the solenoid, it just holds the solenoid in its fully-in position. That takes less current/voltage. The solenoid is "pulled in" when the Pilot button is pressed in by the person lighting the pilot.
Actually I did mention that it is pilot operated. I did not explain the operation of that part of the valve because this video is more about how the pilot safety works than how the gas is used to open the valve. Perhaps I should do one on how a pilot valve works. Thanks for the thoughts.
GFM
That's the key part of the system that I was wondering about; this video cleared it up as the pull in current for any kind of useful solenoid would be far too high for a thermopile to drive, but since it's the human operator that supplies the force to pull it in, only a small amount of current is needed to maintain it above the drop out voltage of the solenoid coil. Your further description of a gas pressure operated relay completes the system, as the main gas actuation has to be done without human intervention.
Great video, thank you for taking the time to explain these type of gas valves. Although not used in modern furnaces, you still find these in gas operated hot water heaters.
Welcome
GFM
Really enjoyed your presentation. I work with them all the time. Never took one apart due to possible leaks and you can't rebuild them. So I just throw them out and get replacement.
For a long time I have wantes to know how the gas valve operated in a device unattached to the mains electricity supply and no battery. Wikipedia was useless, only explaining how thermocouples worked which I knew already. The thermocouple-operated miniature solenoid came as a surprise as I would have thought that the thermocouple would not be able to operate a solenoid under its own power, but it does. A great explanation and a great series. Thank you.
crazeygrazey
I finally figured out whats wrong with my gas fireplace!!! Thanks to you. Couldn't find info on it anywhere
Glad you got it going.
GFM
This is a marvelous set of views of the inside. Thanks so much. Any additional explanation you can provide will be as useful I suspect. I direct people to your video.
Solid information. Thanks for posting your videos. I'm going to R&R the gas valve in my fireplace today. Watched your video on that, too.
+Mike Florey Welcome
GFM
Had the identical unit and this was a big help in helping me understand the operation!! You the man!!!!! Heater back up and running! Thankls a million!!!
You are the best instructor in HVAC . I wish you have an happy thanks giving to you and your family .God bless you .
+quang nguyen Thank you and the same to you.
GFM
GFM I think you left out an important part of the valve Solenoid. Thermostat is suppose to switch the heater on. Come across where not enough voltage on the micro thermostat and does not switch the valve on. Pilot is on but therm does not turn on valve.
What the heck are you saying?
GFM
I see this problem alot, on wall heaters were pilot is on and thermostat is not letting the gas flow. Checked at the thermostat, jumped and gas valve turns on just fine. I believe this is a problem with solenoid but I could be wrong. On a milivolt system
I guess I should rephrase my comment in a form of a question. When th pilot light is lit but the milivolt thermostat does not turn on gas valve. But thermostat is checked and working fine also on top of that wires being jumped at the Thermostat and then the Heater fires up just fine. I don't know what causes this problem. Is there 2 soleniod valves 1for the Thermopile and another for the main valve when switched at the Thermostat that turns on heater? Sorry for the dyslexic comments before this one.
That is awesome! I have worked with these valve's for years but did not want to take one apart because they can be pretty expensive, also time. Thanks!
thanks, video took out that intimidation factor and i replace the valve myself
I love your videos ever since I started in this field 7 years ago. I have a huge textbook which pairs nicely with your videos thanks so much for the teachings. im a maint. supervisor at an apartment complex and I recommend your videos to new techs to see the correct way of doing things and principles behind proper operation.
Carlton Joe Thanks for the support.
GFM
Thank you for your showing, really helpful.
The best explanation I have seen . Thank you.
Great video, I always wondered what was inside of these.
We are learning about these in school and this helped me out allot thanks.
Welcome, good luck in the business.
GFM
A while back I replaced the combination gas valve on our 1964 furnace. Thereafter, I noticed that the burners made a whistling sound (most likely from the gas orifices on the manifold). Eventually, using a water manometer, I dialed the manifold pressure down from 3.5" to 2.75", and the whistling was weaker. Fast forward to today, and using a digital manometer I fiddled with manifold gas pressure again. It would not go above 3.5", and would not go below about 2.66". At around 2.85" the whistling became quieter. Later today, while on our daily walk, my wife comments that the furnace always whistled!
Gotta listen to the expert.
GFM
Freaking brilliant explanation! I am wiring my millivolt gas fireplace to a WiFi module for Alexa to turn off/on cause the girlfriend is lazy. Needed to understand how to the valves worked and where I needed to set the transistor-controlled switch to give the 700mV to the main valve.
Thank you Sir, I think you are absolutely wonderful, thank you for all your educational videos.
Welcome
GFM
Thanks. That helps me understand why the regulator adjustment is so "insensitive", meaning that one screw rotation changes the pressure just a small amount. I guess the screw tensioning (or relaxing) that big weak spring centered on the diaphragm.
NICE DRILL OLD MAN
very good video that explain this valve ! Thank you so much !
It is a gas pressure regulator for the manifold. It is a flame safety control (thermocouple flame safety). It is a manual shut off valve. It is an electrically operated solenoid valve. Hope that helps.
question. I took apart a thermostat (KKTB type model), for a convection oven (gas stove burners and electric oven). has baking (BA), broil (BR) and C(convection?).
when i turn the knob for oven the heat element won't go on (I never used the oven after years and this is like the first time I used the oven function - so it can be considered first time). the oven at first came on very high temperature and then after wouldn't come on again.
i took it apart to diagnose what the problem could be.
the oven part is mostly hardwired, thermostat -> relays -> heat element (bottom and/or top).
when i took off the thermostat the parts inside imploded,
i put it back together but it seems that the 2 leads (+ and -) going to thermostat to control whether on or off connection is made are always connected state. the springs holding the bracket regardless of whether they are pressed or depressed, a connection (continuity) is always present. this is the only logical way i could find to assemble it back yet it doesn't seem to be correct.
there is two brackets, one braket moves kind of up and down to connect to the leads. the other has a spring attached which goes back to the first bracket.
then there is the second half of the box which has a round metal piece which is connected to the thermostat sensor, this goes on top of the first bracket.
any idea about this type of thermostat?
Thank you, GFM. This is exactly what I needed. I've been working on an older ventless gas fireplace log in my home and couldn't figure out the regulator system. You are a good teacher. -- Bob
Thank you Gary. 🙏🏾❤️
been wondering about this valve... thanks!
Great explanation. This type of valve is on a lot of builder drop-in fireplace units. I was getting mixed up about where to check the thermocouple voltage, now I understand why there is no terminal for it, it's that copper line into the solenoid. Thanks! Unfortunately I still don't know why my fireplace won't light... I got voltages that now check out after cleaning the thermopile -- when it initially failed the voltage was too low and they were fithy. But it still won't light. The troubleshooting things says one other test beside the thermocouple -- to check a the continuity from a safety magnet to ground -- which I can't find. I guess I'll have to replace the whole valve assembly.
Have old Warm Morning heater that I love. It has fan that is not used. It has the same on/off/pilot valve as pictured. Tan, push down for pilot turn to on when It has started. Easy to start. It periodically starts roaring when running, nothing consistent. From quiet to softish steady roar. I jump up, turn it to low and it often stops the roar and I quickly turn it back up and it works fine with roar gone. One time I had to turn off the gas at the pipe and right back on when just turning it down did not stop it. Since there is no motor running - just the gas coming through the lines... is it air coming through with the propane? Sound old tank is half full. Old regulator? Smell no leaks. Went through a spat of this happening around 4 am on cold mornings, but that seems to have quit. Out of the blue, it just did it again this (cold outside) evening. Help!!! No one seems to know what I am talking about. Thank for any help.
Awesome video, love the detail, I just learned all there is to know about it in 8 minutes, how great is that??? Thank you...
Thank you craig
Great video can you do a video explaining the terminals on the gas valve and what they do exactly? Thanks
Great video! When I light my pilot the button doesn’t pop up quickly, rather it takes almost a minute to pop up high enough to move it to ON. Should I be concerned? 1977 Lennox (I have a video on my channel). There is no screw on the button or I would try to put a drop of oil where the screw goes. I don’t see a way to lube it...
Thanks for your efforts. Very helpful ! Keep it up !
Welcome
GFM
This is a great explanation. Many thanks
Welcome
GFM
Thank you for sharing your knowledge :)
Great video - thanks!
Welcome
GFM
the pilot flame on our 1964 furnace used about $6 worth of gas in one year. Hardly an energy hog.
Super helpful, thank you
Welcome
GFM
Another great video
+Vincent Padalino Thanks for the support.
GFM
Great video sir thank you
Welcome
GFM
good explained
Thanks so much for saving me the trouble of curious disassembly! I run an electronics lab and was curious as to how a ~30mV signal could hold a solenoid open without extra amplification circuitry. It's also nice to see the thermocouple solenoid come out so easily; a couple of additional pointers may have been helpful such as: can you simply take out the thermocouple solenoid while the gas is switched off? and can you generally purchase the thermocouple solenoids by themselves or must you purchase an entire combination valve?
Thx man good video
Excellent
Thanks brother
Welcome
GFM
Yup... You explained that beautifully. I hate New electronic ones.
Excellent !!!
Excellent job Thanx.
Welcome
GFM
I see how it works, now to find one showing how to adjust.. Have one without any electronics, from a Warm Morning space heater. Just bought it, yellow flame with mixture door open little more than 3/4 and weak pilot, hooked up to regulator for twin 20# tanks so that may be issue. But wanted to turn down flow as mixture is already open quite a ways, and turn up pilot a little.. Pilot goes out when it senses up to temp and flame goes out.. in a camper, have small door for airflow behind, this regulator and twin 20s serves a 30k BTU furnace and this is same BTU for max output, 9-30k, so thought would work, plan on switching to twin 100# or pig, just testing this used unit... There were 2 chrome caps and a door that swings open that says vent.. Looking online for model series to go off of, Honeywell so should still be able to find resources.. May check out your other vids to see if you deal with this style valve, but will keep looking to get this project done...
V5267F1007 was my valve, hunting for info now,, there is an adjustment on the hi-lo side under a cap hinged by 1 screw, then other side has 2 chrome caps, 1 with arrow and another says vent... so far would assume, the one under the chrome cover was pilot and the one under the sliding cover was flow control..
Lovely! Thank you.
Welcome
GFM
While pressing PILOT, eventually the solenoid keeps the pilot light valve open. So what then does the ON setting do? I'm trying to follow how the ON valve is first but the pilot light valve opens first ? Thanks
Emphasis on "hold". Except for certain limited applications, they will only hold a pilot valve open. Check out HVAC part suppliers on the internet looking for general replacement combination gas valve.
GFM
There should be a cap with a screwdriver slot with the words "pilot adjust" near. The adjustment is under the cap.
GFM
impecable 10 puntos
Very thorough videos. I installed a Williams Montery (wall furnace) that I bought used. Didn't work until I replaced the thermopile. (I disassembled everything except the burners and control to clean the furnace.) Then the pilot ignited just fine but the burners did not light. The troubleshooting guide said to replace the gas valve (Robertshaw 710-502) which I did. The furnace now works very well. I took apart the old valve to see what failed. Everything looked good. When I tested the various terminals for continuity, I had good results. There is a wire from (what I think is) the burner control solenoid over to the terminal block. I get continuity there too. Should there be continuity when the valve is not connected to a source of electricity? From your articles, I get the feeling that this is a short, leading to what some call a "stuck valve." Is that what it could be? I couldn't pull out the soleniod, but based on your article for "chain control," I suspect that it the problem. Please comment.
Hi i have a pitco frialator fryer and it works fine but right before the temp starts to drop and wants to turn back on i smell gas than it turns on and the smell goes away and i thought that the combi valve is bad and replaced it but still have the same problem thanks for your videos.
Do the solenoid ever go bad... if so, can it be replaced .... I’m thinking... yes, no????????? ...I’m working on a Honeywell V810A1210 gas valve and the price brand new is $365.00 .... haven’t tested yet( the thermocouple for DCmv) ... just want to cover my bases, as you know it’s a old furnace.....you showed in your video, the seloniod... trying to look for this part.... can you help me please....
Williams Enclosed Hearth Heater model number 5001911. Pilot stays lit and main burner not firing up. Attempted to purge the air out of the line via the pilot tube but found minimal gas pressure in line. I heard no gas flow when opening the shut off valve to purge.
Replaced integral twin stage regulator out by propane tank. Pressure is audible now and enough to purge line.
Pilot light stays lit with blue flame
Millivolt reading 30mV on thermocouple.
Pilot knob is set to "ON" position.
Problem: Turning the control valve to maximum, gas valve not opening.
After shutting off pilot light, 180+ seconds later the "click" can be heard of solenoid disengaging from magnet in gas valve.
Question: How can the solenoid open and there be no gas coming out to the burners? I'll cut and paste this same question on some of your other videos in hopes of getting it noticed.
Your system is, I believe, a thermopile system. The thermocouple holds open the pilot solenoid. The thermopile operates the main solenoid. I would guess the thermopile is weak or there are loose connections. Hope this helps.
GFM
Thank for you this video, it was very informative. So if my flames on my propane deep fryer are not blue but yellow, which way should I turn the regulator? I was told they should be blue so they’re burning at a high enough temperature.
Turn the regulator Clockwise. There’s a reason why you’re not getting enough gas. A manometer should determine the w.c pressure. Should be 10-11 for LP and 3.5 for Natural gas.
great video what would keep the pilot knob stuck at the pilot position. I won't turn on or off
The valves sometimes jam inside the valve. Means a new valve.
GFM
Stay blessed always, clear and precise. Are these considered multi-function gas valves? Are they used in gas fireplaces?
This type valve operates on 24 vac. It can be used on most pilot safety applications. There is a millivolt type that operates only on millivolts usually for fireplaces.
GFM
I can’t figure this out anywhere. I’m using a patio heater with the Shaw pilot knob. I have been looking for an explanation as to how the knob assembly works. It’s supposed to turn easily from off to pilot, then you must press down to light the pilot and then it will continue to the full on position. You can manually hold the pilot knob down and turn it to on to ignite the burner of the thermocouple doesn’t work (it shuts off once you stop pushing the knob).
I was fiddling with the knob and it seems as though it got reversed mechanically? Now I can’t turn it to the off position without pushing down on the knob, but it will turn right from off to on without pressing down. (The opposite of the proper mechanism behavior) I was trying to learn how that mechanism works to fix it but that wasn’t discussed here (or anywhere) have you heard of this happening?
I probably cannot be of help here. The only thing I know is that if the knob gets stiff, you are pretty much stuck with replacing the valve.
GFM
The safety valve operation is understood. When calling for heat, the large gas
turn on is a little murky to understand. Electric from the same thermocouple?
If the valve is a millivolt controlled valve, it uses either the thermocouple or a thermopile to power main gas.
The valve could also be powered from an outside power source. Either 24 volts or 120 volts. Hope this helps.
GFM
grayfurnaceman Thank you. My 1962 model gas valve does not have any external power supply for the main valve operation. BUT we do have (2) two pilot lights. yes, two. one thru the gas valve for the primary valve and a SECOND
pilot outside of the valve DIRECTLY to the pilot. Thank you once more,
Only power comes from the therm..... whichever one we have.
@@tedlahm5740 It appears to have a millivolt control.
GFM
Hi Mr. Gray: I have a ventless gas stove and I would like to convert the thermocouple to an external digital type. If it's possible, can you explain how that can be done?
I just installed a new pilot assembly W010-0790 ( it has both a thermocouple and thermopile ) on an old Napoleon fire place. It has a Robertshaw/Grayson gas valve. My problem is that my gas valve doesn't have a port to thread in the single copper wire from the thermocouple. I think my gas valve has a wire coming out of it that used to go to a separate thermocouple control ( probably held mercury ) that they no longer make. Can you tell me how I could get this hooked up ? Thanks in advance !! Jim ODonnell
Hi , I have one of these valves from my old 9,000 Btu camper furnace , Its a Honeywell version , could not find the model # ,, on miy valve the Pilot , on off knob will not turn anymore , its stuck in the Pilot position , I have taken it apart and cannot figure out why . Any ideas what could be stopping it from turning ?? It isa 1976 year model , thanks ..
It's not the voltage so much as the current. For a sensitive solenoid having a high number of turns of wire, a few milliamperes of current is all that's needed to move the core.
Do you use a sealant when putting the valve back together? I opened an old valve to a wall heater and freed up the stuck diaphragm. But didn't reuse because I didn't know if a sealant was needed?
Under no circumstances do I repair and reuse the combination gas valve. Its just not safe. This video is for explanation only.
GFM
Hi, i hear a clicking sound from gas valve when thermostat calls for heat. But the pilot is off. Does this clicking sound means that the gas valve is being energized and gas is going to burner even though the pilot is off? Thanks
The pilot safety valve is in series with the main gas valve. If either valve is closed, gas will not flow, either to the pilot or the main gas in virtually all gas valves.
GFM
does this valve works the same as those dual intermittent pilot gas valves that use with intermittent spark ignition module? i was working on a york RTU with two gas valves. the terminals on the gas valve were TR, TH/TR, TH. the TH/TR was connected to PV of ignition module. the TH was connected to MV of the module. the TR was connected to ground. if i were to measure from TH/TR to TR i should get 24vac to open the pilot gas correct? and if measured from TH to TR i should get 24vac to open main valve for burner correct? so does this mean this gas valve has two coils? one for pilot gas and one for main burner? thank you.
I see that you can get rebuild kits for some gas valves. Is it worth it? Thanks for all your videos. I’m learning more here than I did at tech school.
If you are talking about combination gas valves, the manufacturers will not sell parts for them. There are rebuild kits for some regulators and manual valves but nothing I have seen for combination valves. If you know of some, I would like to see what you have found.
GFM
Hey really appreciate the video! I was just wondering if you could explain what it means when the pilot nob does not spring back when released (in the pilot setting). For example, the pilot lights as normally during start up procedure, however once I let go of pressure on the knob, it does not spring back to the closed position. If I slightly tug on the nob it then shuts off.. In the owners manual for the unit, it specifically mentions if this happens then to shut it off immediately and call for a qualified service/maintenance provider. I have shut the unit off, just wondering if this is typical of a specific problem? I am sort of assuming it will need a whole new combination gas valve?
If the knob does not pop back up when released, it is now a safety hazard. It must be replaced.
GFM
I have an old furnace. I tried to use this a few days ago. I turned the heater on via thermostat, and no warm air came out of the vent (but the fan was turning). I checked the pilot light and it was off. I re-lightened it (meaning gas was there). I turned the heater on again, with the same result. I checked the gas valve, TR and TH, 27V AC was there. Any suggestions?
Using your info, the gas valve has failed.
GFM
My gas fireplace has a Couple and a thermopile. Why does it have both of these components?
The thermocouple is for flame safety.
The thermopile is to power the gas valve.
GFM
I have a head scratcher. I smell gas when my boiler lights up and it takes longer (30sec) to ignite than before. Weil Mclain boiler, steam over gas system. Lit pilot. Has a robertshaw 7000erhc-s7c vale. Says it has slow opening feature for soft ignition. Any ideas before I replace the valve? Looks like the one in your vid. No complaints otherwise and everything looks visually good. Thanks for good vids.
First, I would try cleaning the burners.
GFM
I have a garage furnace with a White Rodgers combo valve. The TC is making over 25mV. I think I have a bad TC connection to the solenoid, open solenoid coil or stuck solenoid. Is it possible to test the pilot solenoid coil resistance with the TC disconnected? Black meter lead to valve body and red to the solenoid connection? Thanks if you can help
What happens when the button is released? Pilot goes out? Stays lit?
GFM
Thanks for the video.
My problem is the flame goes out after I let go of the knob (after successful ignition), so I suppose is the thermocouple's fault.
SS Lee If the pilot flame is blue and covering the thermocouple, you probably have a bad thermocouple.
GFM
Any advice on where the adjusting screw is for the pilot light flame on a Tiara II-B ? I replaced the Thermocouple Assy. with a new one from H+Home Tech. Tagged all wires, etc. and replaced as undone. Everything works, including the remote Themostat and control. However the pilot flame is 3" or 4"+ High and wide coming out of the pilot hood. Thx.
There is a pilot adjust slot head on top of the valve. Marked pilot.
However, if the pilot is that high, you probably do not have an orifice installed in the pilot tube where it connects to the pilot assembly.
GFM
This is exactly the system I have and even thought the thermal coupler was changed heater won’t stay ton for long time . I’ll hear a click and pilot is out. I can relight pilot light but when I turn to gas it goes out what to do ?
The reasons for that type of failure are numerous. Is the pilot covering the thermocouple at least 3/8"? Is there any draft hood spillage? Is the thermocouple tightened reasonably?
GFM
My do some, whit red flame why?
I have this gas valve but with an ignition system pfg8. Keeps cutting on an off can it be the valve ? Should I change the pilot solenoid first ?
The pilot solenoid is not replaceable on the gas valve.
If the pilot safety was opening, it would not relight.
I would be looking at the low voltage controls such as the thermostat or limit switch.
GFM
Help! I have standing flame furnace with a 36c53-418 gas valve. The pilot keeps going out after 1-2 hours. I've changed thermocouple and high temp sensor. There is no flame roll-out. Earlier today I reignited the pilot, set gas valve to on, thermostat clicked and burners roared and fan forced air... the thermostat reached temp and burners shut down but noticed a flame sputter at base of burner tubes (where they meet perpendicular to gas tube going into furnace chamber) leading into furnace - pilot remained lit. I raised the temp on thermostat and furnace went on normally and again sputtering at base of tubes leading into furnace when thermostat reached temp - pilot still lit ( nice fanned flame hitting thermocouple). On the 3rd sequence the thermostat sent signal for heat and boom like a backfire the pilot went out and I can hear the gas hissing. Shut off furnace and gas line. Can this be a faulty gas valve 36c53-418. Cold n almost blowup in NJ
The first thing I would do is clean and readjust burners.
GFM
Hello, what are the 4 functions of that combination gas valve, if you would be so kind????
Its hard to believe that 20mv and can hold the solenoid open I can think of a few projects I could use this on.Where can bye one.
What could be the problem? The furnace seems to work like normal. I just so happened to blow the pilot out and the gas continued to flow.
If the gas flows longer than 3 minutes after the pilot has been extinguished, the gas valve must be replaced. It is a safety hazard.
GFM
Anyone know of a good place for parts? I've got a 1978 furnace where the pilot light randomly goes out. Replaced the thermocouple a few times and then called the professional. When I told him in the street what I had he insisted it was a the gas valve and $100 later said I need a new furnace. I noticed my pilot light burning dirty while he tinkered. Hoping he was wrong with obsolete parts as the thing works great as long as it has a pilot
Hi, is there a way to get a replacement solenoid for a gas valve?
No. The valve parts are not replaceable.
GFM
Great stuff GFM! Thanks fr putting forth the effort to help educate others!!
Question... I have an older Empire Rh-65-1 space heater. This unit does not use any electricity. I had some problems that I think I've resolved. I've taken the burner and the main burner orifice out and cleaned them both to get rid of the loud resonating and yellow flame.. I have the primary air adjustment screw turned all the way in but still get some extinction popping and occasional resonating (but not nearly as bad as before cleaning). I notice a small yellow flame about 1"-1.5" at the main burner orifice when the pilot light is lit and no heat is being called for. The thermostat seems to be working fine as I can turn it up and it lights the main burner every time. But when the temp rises and the burner kicks off the flame is still at the orifice. I am concerned that the gas valve is bad? Empire sells a replacement valve R1624. I believe that is the Robertshaw 700-204? Its almost $300 through Walmart. Im not opposed to replacing it but don't want to spend the money if there's a cheaper fix. Any help here would be greatly appreciated!
The leaking by of the valve condemns it. I would not use the heater with that valve. The 700-204 is a hydraulic valve probably similar to the original. There could be some mounting issues if there is temp control rod mounted on the valve.
GFM
So if the pilot won’t stay lit after replacing thermocouple?
If there is no ECO in the thermocouple circuit, and the thermocouple is clean and tight, you have a gas valve problem.
GFM
the flow control adjustment that you shown in your video, is that for the pilot of the main gas flow control for the burner? I want to get a gas flow control valve that can have a wired thermostat that runs of a power pile. My existing heater is an old Coleman dual sided wall heater and it inconvenient to adjust the heat and a wired thermostat would solve that problem.
There are 2 flow controls on the gas valve. One is a set screw for the pilot adjustment and the other is a manifold pressure adjustment. Neither will work with a thermostat. However what you may have is a hydraulic valve that has a temp sensing bulb and an adjustment to change the gas flow to the burner. If it is a hydraulic valve there is no way to control except by adjusting the knob.
GFM
@@grayfurnaceman I was planning on purchasing an entire Williams Monterey Plus gas valve, thermostat, stack senser, and pilot/power pile and removing my old gas valve to replace it with the Williams equipment. Thank you for your response!
What is the most common reason that a gas valve pilot will light but won't pass gas to keep burners lit? Have run into this a few times - normally we just replace the valve.
If it is a standing pilot, and 24 volt power is available to the valve, either the valve has failed or there is a supply problem.
GFM