How the electric elements on an electric furnace work Part 2
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- เผยแพร่เมื่อ 2 ต.ค. 2024
- Just a demonstration of electric elements sequencing on and off.
This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.
That's about it. The fan pulls the heat off very quickly. Mostly the glow is from the ceramic mounts that reduce air flow. Thanks for the comment.
GFM
You do a great job , I love your videos
Great
Electric furnaces are similar to all furnaces, depending on how many elements are used. Duct temp is usually 120 degreesF. Amount of heat provided is very close to 100% of the energy used as there is no stack loss. Hope this answers your question.
GFM
But how do you prevent the connections from melting? the connections between power source and the glowing element? I can see in the video that these connections don't glow, how is this?
grayfurnaceman do you have a wirering diagram for wirering them up
grayfurnaceman we have an electric furnace and I can read with a infrared thermometer gun 200° F
Can this be used for a big basement.... freestanding!
grayfurnaceman recita de torta se fangro
Cool!! Never seen an electric furnace! Interesting to see how they work.
That's a maximum temp for UL or GAMA testing purposes. With the limit switch bypassed either furnace can out put very high temperatures. An example for electric would be a self cleaning oven that reaches temperatures of I believe 1200 degreesF.
GFM
My second stage only works only if i tape the top control board,the heater is 50 years old
Great informational video, I did commercial heating and cooling for 16 years but needed a refresher update for electric residential furnaces. Your video series has been a great update course and I can now install and service my new electric furnace with confidence.
Thank you so much for the education.
Harold
I replaced mine. There is no continuity to the frame. Ceramics are good. But here is my problem. I strung a new lime like the pictures. Mine does not glow all over. Mine has no areas of red then just after a dead spot the element looks like molten metal when using an oxy-acetylene torch. I’m afraid it will burn out. Yes, after in insulators all have same super bright about to burn. Was I not supposed to touch it? It also seems like around the corners are cold but when straightens out and coils closer together those close ones glow. So mine are patchy. The resistance is 13.7 for all of them. What am I doing wrong?
Are those copper wire?
The wire used is a nickel chrome steel alloy.
GFM
Hello Sir. Thank you for your videos. I have two questions. I own an Electric furnace which is coupled to an exterior thermal pump (It is an older Carrier 3 pieces system :) ) IT is a 15KW system with three 5 KW elements on the heat strip.
One my coil is shorted and not working anymore. It is the number #1 element, so the first to be called on when the heat pump stops (-10 c). My other two elements coils are working fine.
I was under the impression that when my heat pump stopped because of colder temperatures, the system would try to call on the first coil....and after while seing no heat was produced would then call on the second coil...and third coil afterwards if necessary.
It seems to be exactly what is happenning and this is my second winter with only coil #2 and #3 working. Am I right thinking this what the furnace system is doing???
I live in Quebec, Canada so we have very cold and hash winters. Altough my heatpump is opten in use because it is above -10c, even in very cold weather (-20 to -30c) I never seem to have a problem with only element #2 and #3.
Also I have put off re-stringing the defective coil because I also have 240v heating baseboards in every room as a backup if the furnace would fail.
To re-string it I would have to do it in spring to find out the real diameter of the coil to buy a similar part. My 2nd question is could I just buy a generic replacement coil before taking it appart and just put it in the 3rd position. Does the coil diameter makes that much of a difference???
It could be working with only the first coil energized if there is at least 2 outdoor thermostats. You do need to know the diameter of the coil before replacing.
GFM
i use 1000w heater for cooking but sometimes i feel like to reduce its power (heat) to half. what and how can i do this.?
Buy one that is 500 watts.
GFM
On my friends Bryant Electric Furnace we found a broken element, which was replaced, and it glowed when the furnace was turned on, however no heat came out, this is a stringer heating element. The next day the elements would not come on at all. Replaced the sequencer and still no heat. Can not afford to call a real repairman what can we do next? I have viewed and reviewed your videos.
Hello Sir.I have a EB15B electric furnace and I'm having a problem.I have replaced the sequencers, all three limits, and both of my heat strips are working.But when I turn the unit on I'm getting coldish warm air and after 3hrs it only bring the temp of the home up to 68 degrees.So I decided to remove the blower motor and look at the heat strips while the furnace is on and after I start the unit about 5-10 sec I hear a click and the bottom heat strip goes out, and the top one stays on, but the bottom one does not come back on after a min or two, in fear of doing any damage I shut off the unit.Can you please help me with this problem??
got a furnace with 2 elements like this, not getting much heat from my vents, both elements kick on but they appear to only brighten up a little in small spots but stay dark around majority of the elements?
My house electric meter had a seizure while watching those glowing coils .
Sometimes it blows out the bearings.
GFM
Whenever you wire for a furnace ( electric ) it needs 240-volts, correct, so what I want to know how come the breaker doesn't trip when the elements come on, a phase and b phase coming together at the strip,
The element is a load. A load is a current limiting device. You seem to think it is a dead short. It is not.
GFM
Is it possible to use this type heating element from a old heater in a forge? i have access to some old electric heaters and would like to use them for that type of use.
Possibly.
fairly costly, I would think...
Do can you tell if your electric furnace is putting out a decent air temp for heat.. it feels cold
You can try using a thermometer at one of the diffusers. It should read about 120F
GFM
Hello came across your video while trying to figure out why my heat is barely warm unlike the element in the video my element when cut on both lights up then the bottom cuts of . Do you see that as normal
Sounds like an air flow problem. Limits are probably opening. Check air filter, fan blade for dirt, A/C coil for dirt and possible ductwork problems.
GFM
@grayfurnaceman Thanks so much I'll try these things
mister. what if it is used for aluminum smelting furnace, where the position of the electric fire spring elements is placed ??.
I have no idea.
GFM
@@grayfurnaceman its soo nice that you still reply :) respect man
My blower fan inside my electric furnace will blow about maybe a minute after heating element turns off and when my air conditioner outside cuts off is that normal?
Yes, some units are set up the clear the heat from the ductwork.
GFM
My electric TAPPAN furnace is blowing cold air, What do I have to replace?
Ahh, the answers could fill a book. First, try resetting the breakers. Then, check the control box (with the power off) for burned wires. Check that and we can go from there.
GFM
May I ask one more question? What are the 10 half inch holes, 5 above the elements and 5 below that blow heated air onto the sequencers. Seems like the cooler any electronic component the better
When it's -20c, it's not really hot, I think that one of the element is burnt out, how do we know if it is? When it's -10c, it's okey but when it's very cold, there is not enough hot air. We've been using this furnace for 20 years.
First, I would check all breakers to the furnace in the main panel. There may 2 or 3. If there are any fuses or breakers at the furnace, check them. Turn them off then back on. If you are confident in your abilities regarding electricity, you can look inside the furnace panel. Look for any burned wires. Next you are looking to sequencers or elements. Here you need a meter and the ability to use it. Let me know how you do.
GFM
Thank you for the fast reply. I have turn off and on the breakers and the fuse. Since 2 years ago, I covered half of the intake air from outside the wall to keep warmer, replace the new filter.....,
I will check there is any element burned.
So, is the coil heat strip bad if only parts of the strip glow when it's heated? I took out a heat strip from a tempstar heater and when i put on the temperature varying from 75 to 85 and only the bottom parts of the heat strip glowed red.
Can ordinary coiled wire resists T° up to 1000°?
The wire can handle up to just below its melting point, but many types of wire will oxidize at the high temp. That is why we use nichrome wire for heating elements.
GFM
@@grayfurnaceman thanks,,,can 1500 watt wire resist?
@@girar813 If the wire is made from nichrome, it probably will.
GFM
two of three elements broke they shorted each other out is it safe to twist them back together I twisted them back temporarily please reply thanks
+vodka high They will fail again. I would restring with new wire.
GFM
ok thank it worked for a lil bit but it got hot cold hot cold etc but thanks for your time i will get new wire
rick carp hi
It does. But an electric furnace doesn't produce heat output above 120 degrees Fahrenheit gas furnaces can can provide a heat output of up to 180 degrees Fahrenheit and hotter with some furnaces. My gas furnace, for example has a designated maximum heat output of 185 degrees Fahrenheit on first and second stage operation.
it just like a fan heater that you put on a desk the blower keeps the heating element at a fix temperature so the coils will not glow really yellow like that when there in the furnace although they will still glow a little in some cases kind of like a faint red sort of glow
can I use 10,000 w electric element (Furnace) on a 50 amp cable Fifth wheel ?
I would not. You need a 25% fudge factor. And that's with no other loads.
GFM
@@grayfurnaceman Thanks, 5,000 w is the maximun can use with the 50 amp cable.
My heater started burning one leg of the breaker. All 3 elements ohm to about 11.5 ohm or so and no short to ground. I tried running the blower by itself and the breaker at the bus bar contact point only gets to 68 degrees. When the heating elements run one leg shoots up to 200 degree within couple min so I turned it off. The connections seem good. I cleaned the bus bar with a brass wire brush on my Dremel. I thought it was just a bad breaker but it's not. Anyone have any ideas? I see these little resister looking things mounted with my elements I have no idea what they are. Maybe I'm searching in the wrong place here. Nothing seems to be grounding out anywhere
Go back to the breaker. 2 things cause breakers to overheat. Loose connections to the wires and a breaker failing inside. Tighten the wires and if it continues, the breaker is failing. btw the resister looking things are hi temp element fuses.
GFM
@@grayfurnaceman I replaced the breaker twice and checked all the connections... What's stumping me so hard.. I even changed the breaker again to be sure and each heat at one leg. It only heats directly at the bus bar on the one leg that the elements are ran off of. I tried running the blower only and they heat evenly to maybe 70°. I even cleaned the wire with a brass Dremel wire brush (was clean but did it anyway) and the bus bar as well to be spotless. And made sure I torqued the connections good. Went inside the unit and did this too. I checked the elements to all about 11 ohm which I thought is good. So if those resistor looking things are fuses that rules that out. Thanks for the quick response. But that's what I did first twice already. Is there something else that could try to make connection but be soft and causing extra resistance to the breaker contact? How hot should a metal breaker contact be allowed to reach?
First, breaker terminals should not heat at all. Have you checked amp draw?
GFM
@@grayfurnaceman my clamp meter claims 2.2 amp on one leg with only the blower running and 45 to 46 amp on one leg with the heat kicked in. Any reason it would draw so much? It's a cheap meter unfortunately no fluke
Check both legs they should be the same.
GFM
So that was an explanation of how they work?
Standing near it does it feel like standing close to a bon fire where you feel like the your face is hot through infrared radiation?
If you are very close, yes.
GFM
@@grayfurnaceman I meant infrared radiation* similar to how when you stand next to a toster owen and you can feel the inferead radiation from like two feet frim the glass door though the glass even though your not actually inside the owen where it gets hot. Or how when you stand near a bon fire and feel warm on the side facing the fire even though the heat rises you feel warm from the inferead radiation.
@@mattdaddy_888 Yes, it does.
GFM
I have question i call service technician and he mention that my heating coil is bad its not working well he said its running only on one leg right now soo after he left i try to check the heating coil and its looks fine i also check while its running both element looks red but not like yours doess... so you think my heating coil is bad but still running is it possible..?? I thought once its broke it won't run at allso help me if you can please thank you in advance..he was saying it should put 20amp and its only giving him 15 amp
I have 4 elements in my furnace. Is the #1 element the one closest to the blower? I think mine is wired wrong because the one furthest from the blower is the one coming on first, and when they shut down they do not sequence down. The blower and all 4 elements stop at the same time.
I have seen them set up both ways. The sequencing off at the same time is common.
GFM
Bro which elements uses in hetar
Great videos thank you so much!
Thanks for the support.
GFM
Pretty much what I expected, thanks for the video
0:30
That"ll get your meter running
I have a question. I have 3 elements in my furnace. Sometimes only 2 will light up. One lights up from beginning to end and the second on goes on and off. The third one doesn't light up. Why do only 2 light up? Is this normal?
It is not normal. You probably have a low airflow problem. Plugged filter, dirty fan blade, plugged A/C coil, ductwork problems. The second element is shutting off on high temp limit. The third element could have a failed sequencer, burned wire or open element.
GFM
@@grayfurnaceman It's working fine now and all I did was touch the connectors. All 3 are working fine. Thank you for answering and your videos are fantastic. I learned so much from you that I was able to change a sequencer and a limit switch Saved me a lot of money. THANK YOU!
How red do they get inside i unit cause mine glow. Not nearly like that but some orangish
If the air flow is right, they should only glow around the insulators.
GFM
hi what the cost to run that for 10 min??
You can calculate the cost by measuring amp draw x voltage x kilowatt hour cost divided by time.
GFM
what do i need to do that?
An ammeter, voltmeter and some easy calcs.
GFM
If I were going to use electric heat, I would do it on a room by room basis.
In that case, you would have to use baseboards. Probably the most inefficient form of electric heat. It is not the efficiency of the elements themselves, just the high temps located near the outside walls and windows will increase the transfer of heat outside the structure.
GFM
grayfurnaceman It would also depend on the quality of insulation such as it's R value. But by using individual forced air wall heater units, it would give one the flexibility of heating only the rooms in use.
Consider that interior rooms are not insulated from each other and you simply create cold spots in the structure when they are not heated. Also consider how much better the a forced air system using 120F air would work with the increased R value. Temps above baseboards have reached 400F. It truly is the cheapest but overall the worst and least efficient of the electric systems.
GFM
Jolyon Welsh have a 5-ton York electric furnace just had my power wiring upgraded from 40 amp to 240 electrical box I need to know how to hook up my furnace it's cold
When replacing a sequencer/s, should they all have the same timing or should they be staggered? I have 3 sequencers, 1 with a timing of H1-60 and the other 2 are H:1-110. If I'm understanding correctly, the H:1-60 will kick on first and then the other 2 will kick on after the first but both at the same time. Right?
***** I believe you are correct on the timing. Here is the problem. The first element and the fan must be the first on and the last off. The other elements can go off and on at any time during the cycle. Hope this helps.
GFM
I want to replace the electric strips. Can you tell me where can I buy. By the way I live in canada. Thank you
Are these exposed elements? Like if you touched them with a butter knife, would you get shocked?
AaronLow1 Starting out young. We like you, just be careful. Electricity just waits quietly for you to make a mistake. As for the elements, If you were touching ground with the other hand, yes. These are normally inside a furnace. They were just removed to show them.
GFM
What's the amp draw on this?
Most elements are 5 kw, so they read between 20 and 25 amps.
GFM
if you have burned 12 gauge wires in series with your heat strips why not replace them with 10 gauge?
The problem is not the wire size, but the wire terminal connections. If they are clean and tight, there will usually be no problem. That said, I did often use #10 wire as replacement.
GFM
That heated up fast!
Is electric baseboard heat more efficient than forced air?
Actually, far less efficient in a practical sense. Baseboards have a higher air temp than forced air, which increases stratification of the indoor air.
GFM
@@grayfurnaceman I have oild heat and my WH n Stove are electric. I am installing central air what do you recommend forced air elec coil or elec boiler for my baseboard HW heat?
@@JohnAvantiBK If you are going to keep the HW baseboards, and want to change to electric, about your only choice is electric boiler.
If you change to forced air electric, you must install ductwork.
GFM
@@grayfurnaceman do you a saving running gas to the house or buy an electric boiler will I save allot of money gas vs elec?
@@JohnAvantiBK Natural gas is generally cheaper than electric, but the price of natural gas has been going up. In most areas, it would have to be over $1.20 a therm for electric to be competitive.
GFM
So is an electric furnace expected to warm a house as well as a gas furnace? I believe they don't. If you agree why dont they make one that will. bigger coils , maybe more coils? Why not use a burner like what is used on an electric stove instead of those small coils of wire. The coils dont seem much larger than whats used for a space heater. It seems electric furnaces could be made to heat much better if someone like an engineer put thought into beefing up the coils.
Electric furnaces are quite as able to heat a structure as any other. They are sized for the load as any other furnace is. They are engineered. The coils are generally 5 kilowatts each.
Now for the real problem. An electric furnace, or any furnace will shut itself off if there is not enough air flow. This could be from a plugged filter, or restrictive ductwork.
The only other possibility here is one or more of the elements may not be working because of a failure of the controls or the element itself may be failed.
GFM
My electric furnace works just fine pushes around 125 degrees out the vents and keeps us very warm in 0° whether
Mere heater ka coil jal ja raha hai kyun ki voltage adhik hai koi upai bataye
I have GE electric furnace (air handler) that feels hot in plenum section even when termostat is set to lower temperature and heating(blower) is not running ? Is this normal ?
No. You could have a stuck contractor or shorted element. It needs to be looked at.
GFM
@@grayfurnaceman
Thank you. That's what I've taught. That is why my electric bill was high as well. Heater strip stuck and working all the time no matter if the termostat is calling for heat or not. What do you think about heat pump. I leave in Chicago land? Thank you for your help
If the back heat is electric, its a good idea. If its gas, probably not.
GFM
My electric heater has been malfunctioning. I watch the heating elementt through a small hole when I turn it on and then top one goes on, then the bottom one goes on, but as soon as the fan starts the top one shuts off and the bottom element stays on. The heat won't go above 50 degrees.
Have you seen this before? Do you have a clue of what might be wrong? Thank you!
Sounds like an air flow problem. As in not enough air. Plugged filter or duct problem.
GFM
@@grayfurnaceman I have a brand new filter in there. Same kind of filter I've been using for a couple years.
The heater actually is in the garage, and there isn't any duct work. There is an L shaped vent and it blows into the open air. Vent goes up from the heater, and then a 90° angle.
Should I try with no filter, just for a moment to see if I happen to have a faulty filter?
Thanks again!
You can try the filter removal.
GFM
I know this is an old post but this may be of use to someone else. Sounds to me like the blower fan relay is connected wrong. Here's a good article on the topic: www.hvacrschool.com/electric-heat-blower-interlock/ and here's a video of the same: th-cam.com/video/DfUsThR-JwA/w-d-xo.html
Gary, are there new high efficient electric forced air furnaces cheaper to operate? I have a two stack model, stacks like in the video. It was installed in the early 80's and I only replaced a blower motor and two sequencers since then. So my question is, are new versions more efficient than mine from the 80's.
+GTO Bob 66 All electric furnaces are, for all intents and purposes, 100% efficient. Replacing it would not help.
GFM
+grayfurnaceman Thanx for your input, I enjoy your site!
I have a question, working on an older Stewart "GE" electric funace, its not blowing good heat ...its a 4kw unit air conditioning is also included with this setup.."try to get u better info as soon as i can" went thru everything relays all seem to be working well, element is heating has dual element that both come on at the same time, no delay between the 2 like i seen in your videos..and it dont heat apt. well, warm air is coming out but.....just seems weak to me someone else changed thermo there are 1 red 1 yellow 2 greens , and to be honest with you i dont think it is wired correctly should the 2 green be wired to the same screw? or seperated? try to get you better info later today and check back thx Gray
Green wire should go to the letter g on thremostate thats for your blower newer thremoststes have a built in delay
which elimants use this
Thanks for sharing your knowledge.
Probably a dumb question, but is it normal to be able to see this orange glow when I pop open the panel into the furnace? Ours was making a clicking noise, and when the panel was removed where the motor is, it was glowing orange but only for a few seconds after the heat had kicked off. Thanks!
It is not a dumb question. Not asking it would be. Your furnace has one or more elements stuck on. Probably a sequencer stuck on. This needs to be looked at by a pro. Dangerous condition.
GFM
Future of the furnace.
Do electric furnaces provide a relative amount of heat?
Yes.
you
Very educational thanks bud!
Welcome
GFM
excellent
How many watts do those elements pull?
Usually about 5K
GFM
5kw is about 20 amps at 240v single phase 10kw about 40, exact amp draw depends upon factors that are just unimportant here in this context.
Thanks for sharing the video. we are the factory of heating element /heating resistance wire furnace wire, in China .welcome contact me if you need .
where do u buy the wire lowes?
+vodka high I would try an appliance store. First determine what KW the elements are. Then ask for a restring kit .
GFM
ok thank you so much
Ok cool
Thanks for posting. Does current technology allow only one to come on if that is all that's needed? I'm in the process of replacing a 25 year old heat pump system and learning more with every vendor I meet. One vendor stated that certain coil configurations can be set up to operate this way. For example a 9kw coil can have three stages of heat generation all controlled by the thermostat. Is this true?
The most stages I have seen is 3. Usually there will be several elements that can be sequenced on. Say the temp inside is 69 and is set for 70. One element will come on. If the temp drops to 68 due to higher load, a second element comes on and so on.
GFM
I’m currently in hvac tech school, love your videos , very informative , helps me out a lot when I don’t understand everything in class ..... kinda nervous to get out in the field . I don’t wanna get out there and not know everything I should
School will give you a basis for understanding. The rest comes from the field. I spent my first 2 years reading manuals and taking apart failed parts evenings and weekends.
GFM
grayfurnaceman thanks brother I really appreciate you taking your time out your day and replying , been learning a lot in school plus these videos help me out too , still torn between going into commercial or residential. I was told going from residential to commercial is extremely hard but going commercial to residential is easier. Leaning towards residential because I hope to open my own business one day
Hello .Thank you for yours videos. I have the same question as Lauj Vwj. Is the coil heat strip bad if only parts of the strip glow when it's heated? The mainteinance guy replaced the strips and still aren't glowing completely. Thank you.
They should not glow at all except inside the insulators. The fan pulls all the heat off.
GFM
grayfurnaceman. Thank you for your quick answer. So, thst is normal? Regards.
Yup. Merry Christmas
GFM
Thank you. Merry Christmas.