Just wanted to say "thank you". I was trying to find an easy guide on the troubleshooting order for a 24v fault and this solved my problem. This was buried under a billion "buy a new capacitor" videos- while I understand youtube/google wants to sell stuff it makes finding genuinely useful info on walking back the problem harder to find. Thanks again.
Yes frist checking power high side poper volt ge after 24 vlot checking poper come thtrs gor mer vomd out door one by checking popef rlg trsforom in out 2rvolt come ok thafmost r cc 24vot vomd powed 24 sighl comd ok checkinh lone bg checking out dooer wir cutting csystom poped all checing ond bg all joint checking good fixing sll jonited hp lp powed cotactef clip all poper checkinv fjnd out folved systom
Hey! You just saved my ass... I tested everything besides control board itself and only then noticed after seeing you comment, that drain pump gfci outlet was tripped. As soon as I reset, pump kicked on and AC unit outside started. Woohoo!!!
You've helped me a lot on troubleshooting my a/c. My issue ended up being the transformer. It kept popping smart thermostats by just giving 4-5 too many volts. Thank you for taking the time to make your videos.
I had the same problem with 24 volts. But It's cool days and the people are not using their ac. Well , I had no ac call . After I traced the 24 line , I figured out that another apartment was using the 24 volts wires lol. The maintenance guy a while ago made a big mistakes connecting those cables. But , My friend ,another maintenance guy and myself took us almost 3 hours to figured out the wrong wiring when we tried to check continuity to the next condenser unit lol. Nice video man !!!!
The same problem facing right now in Texas 5 ‐2‐21 my only problem its that my attic space it's so tie l need to get there hoping maybe the low voltage wires are cut in 2 pieces so l can fixed anyway very good video educational!!!!!
The 24V could also be interrupted by a float switch if the drain is plugged or the high or low limit switches that are often in series with the 24V going to the contactor. The latter could indicate a refrigerant problem.
That t stat was still in delay when you first showed it , flashing cool means wait for all you home owners out there (usually about 3-5 min if it doesn’t come on right away ) 👍🏽
If you ever need to get a replacement thermostat I highly recommend the Aprilaire 8444 thermostat it's a 1 heat 1 cool non programmable model I have one and have had good luck with it in the 2 years I have had it
i’m having this same issue and I can’t find the problem, am I supposed to be getting 24 V from each wire? because I have a yellow and a blue which is my common. my yellow wire has 24V but my blue does not when tested individually. So should they both send 24 V or is it normal to just have the yellow sending 24v ?
If this doesn't help check your thermostat, I had this issue and it was just an old thermostat without a digital display so it wasn't immediately obvious
If the Y wire was cut you should not get any voltage between Red and Y wire unless the Y wire was touching off the common which was also cut so that is probably what happened here
Mouse chewed up my contactor wire and when I turned it on first time nothing. I got an old oil furnace with a fan center and I think the short destroyed my transformer relay. Got 120 going into my transformer but no voltage on the red screw...think it's fried...waiting in heat for the new one.
thank you for your informative video Sam. I have one question maybe two though, obviously the thermostat gets its 24 volts from the control board at the furnace, correct? And if so What would CAUSE the control board NOT to supply THAT said voltage? thanks again for any more information you can provide.
Hi Sam, on mine I have a problem. Heater works, fan works. Low voltage fuse was burned out I changed it and keeps burning out. When I set the thermostat to cool it burns the fuse. Tested for 24 volts on the capsitor and has no voltage. Disconnected the thermostat cables that go to the contactor and tested them and they do have 24 volts but when I connect them to the contactor it shows nothing. The contactor does have 220 voltage. Any Idea what may be the problem. Thanks. Great videos by the way.
My situation is a customer changed the thermostat that had a Nest on it. He put on a T2 Honeywell now I can't get the unit to come on. Contactor stay stuck in. I'm not getting 24 volts at the contactor, I check ed the transformer no 24 volts is coming from that as well. I didn't see any break in the wires but for some reason I'm not getting 24 volts at the contactor. I am stumped. HELP. I thought I had a bad contactor and a bad transformer both of them have been replaced with new ones and the unit still will not come on. 🤷🏾♂️. I checked the fuse on the board at the air handler underneath the house and it is good. Customer stated that the unit worked when the nest thermostat was on after he changed it the unit wouldn't come back on so I've been out there twice and I still can't figure it out. The T2 thermostat is a two heat one cool thermostat. Do you think the batteries in the new thermostat is helping push too much current to the contactor that's making the plunger stick to the contactor? The contactor is a single pole. I enjoy your channel very much it has pulled me out of some jams. Thanks for sharing. #PEACE ✌🏾
There are two fans - one is the air handler that pushes the cold or hot air out to your vents. That is located in the attic. The other fan is on the condenser unit outside. He is indicating that you need to have the thermostat in auto so that the outdoor compressor/condenser/fan assembly gets power. When that gets power the air handler fan which is on the inside comes on as well. You just need to make sure your thermostat is blinking cool and that the set temperature is lower than the actual temperature so that it’ll continue to command 24 V to your contactor/outside unit
No. The auto/on switch on the thermostat applies only to the evaporator fan (indoor blower motor) The cooling mode switch sends power to the condensing unit outside. It wouldn't have mattered if the fan switch had been in auto or on.
My blower fan will kick on but compressor will not. If I touch a screwdriver to 24v wire on contractor to the actual plunger metal it will suck the plunger down and kick on compressor. When thermostat hits temp it kicks off. When warms up in house just the blower kicks on and not compressor unless I go out and manually touch the 24v wire contact to plunger metal. One 24 wire comes from a relay looking box above contractor and other is yellow going towards compressor unit. Any ideas? Thanks
Are you getting 24 V across the two wires is the question. If you are I would replace the contactor. In fact I probably just replace the contactor right away. These things go out every few years and it’s cheap insurance and preventative maintenance. They only cost like 20 bucks. They’re easy to replace as well. Just make sure you disconnect the main power but he didn’t go over very well on this video when you’re changing it out
I have an AC unit on the roof of my 5th wheel. When you turn it to cool the relay board just clicks. I don’t see a contactor to test. I’ve tested everything and still nothing. I’ve tested the thermostat, condenser, both capacitors and all test good. I’m not sure what else could be the problem. Any ideas? I’m at my wits end here so any help would be appreciated. Thank you.
It's hard to determine without seeing the issue at hand. If you have tested the electrical components... I suspect it may be the board itself. I have had issues where I was at my wits end and after I replaced the board the system fired up. Make sure that you are certain about the contractor. Usually you can trace the it by locating the disconnect or fuse. The disconnect is what sends the 240 volts to the contractor. Follow the disconnect where do the wires lead to? Also I would advise to test just the fan motor. Turn your thermostat to fan on does it run? If it's a furnace board test the heat.. turn it on does it turn on? If those 2 work then you will have a better time isolating the issue as simply the AC. Do you have the safety switch on your door? Does it work? There are many thing that could be causing this issue... let me know if this helps and if you were able to fix the problem. Thanks!
Sam yes this has a furnace on it as well but neither of them work. When I jump power to the fan pin at the thermostat it just clicks but don’t turn on. The only fuse on the relay board is a small 5 amp fuse like a car fuse.. That I know of I’ve tested everything I really know how. I’m not an AC tech I’m just testing wires as I’ve been in the low volt industry for 15 years so I can at least test the wires for shorts etc but that’s about all I know about AC units. I’m just watching videos and reading online manuals to try and fix this. It won’t let me attach a picture.
Having a simIlar issue where I was losing 24 v going to contactor at a customer's have to go back and re run new low voltage wire since its a 28 year old furnace.
![จบจนได้ ! | Black Myth: Wukong #007 [ตอนจบ?]](http://i.ytimg.com/vi/DSqvWndF0sw/mqdefault.jpg)
Just wanted to say "thank you". I was trying to find an easy guide on the troubleshooting order for a 24v fault and this solved my problem. This was buried under a billion "buy a new capacitor" videos- while I understand youtube/google wants to sell stuff it makes finding genuinely useful info on walking back the problem harder to find. Thanks again.
Find a better training video. This guy is chasing crap.
Yes frist checking power high side poper volt ge after 24 vlot checking poper come thtrs gor mer vomd out door one by checking popef rlg trsforom in out 2rvolt come ok thafmost r cc 24vot vomd powed 24 sighl comd ok checkinh lone bg checking out dooer wir cutting csystom poped all checing ond bg all joint checking good fixing sll jonited hp lp powed cotactef clip all poper checkinv fjnd out folved systom
me too finally found someone who explained and i will try this in the morning ✅✌️ i will reply
Just fixed my outside ac unit without any prior knowledge thanks to you!
Thanks bro. I traced my wires and found out they were losing their protective coating and touching. My upstairs A/C is back blowing now.🎉
Always check drain pan too. Had many customers not even notice the pan under it full. Alot of stopped up drains😊
Hey! You just saved my ass... I tested everything besides control board itself and only then noticed after seeing you comment, that drain pump gfci outlet was tripped. As soon as I reset, pump kicked on and AC unit outside started. Woohoo!!!
You've helped me a lot on troubleshooting my a/c. My issue ended up being the transformer. It kept popping smart thermostats by just giving 4-5 too many volts. Thank you for taking the time to make your videos.
i am new in watching your videos sam. You are doing good, you should be proud of yourself. Keep up the good work.
Thanks to you, I replaced my contactor and condenser and got my AC back up and running for $27. I owe you a cold one.
Wow a condenser AND contactor for 27 dollars? Where do you get your condensers? What a steal
I had the same problem with 24 volts. But It's cool days and the people are not using their ac. Well , I had no ac call . After I traced the 24 line , I figured out that another apartment was using the 24 volts wires lol. The maintenance guy a while ago made a big mistakes connecting those cables. But , My friend ,another maintenance guy and myself took us almost 3 hours to figured out the wrong wiring when we tried to check continuity to the next condenser unit lol. Nice video man !!!!
SAM YOU ARE THE MAN! THANKS FOR THE GREAT VIDEO, YOU SAVED ME A LOT OF MONEY. Thanks again!
Exactly what i expected my problem was...thanks bro! Just gotta hunt down this break
Thanks so much. I had the exact same issue. Followed along and found the problem. I had cut the cable while clearing out the weeds yesterday.
So happy you are taking time out to teach...... Great job 👍
Very good video I had the same problem and would have called the AC guys out but I watched this and found the problem
Great video. Very clear troubleshooting process.
I pulled the 2 wires out the condensing unit box and the white was cracked lol. Thank u for this video
The same problem facing right now in Texas 5 ‐2‐21 my only problem its that my attic space it's so tie l need to get there hoping maybe the low voltage wires are cut in 2 pieces so l can fixed anyway very good video educational!!!!!
We are having the exact same issue here in TX. My other half is in the attic trying to find the wire
Hey Sam it helped a lot I m a HVAC new tech, I m subscribed now nice job
The 24V could also be interrupted by a float switch if the drain is plugged or the high or low limit switches that are often in series with the 24V going to the contactor. The latter could indicate a refrigerant problem.
I love your troubleshooting. 👍👍💚
Great skills & technique! Thanks for sharing!
That t stat was still in delay when you first showed it , flashing cool means wait for all you home owners out there (usually about 3-5 min if it doesn’t come on right away ) 👍🏽
Thanks! Great video - Nice job on visual capture.
Where is the thermostat getting its 24 volts from if thr wore is cut?
Nice job fixing it but those should have heat shrink since they are exposed.
Thank you for your video, I will check my unit tomorrow.
Thank you sam
Thanks. Turned out mouse chewed the cables under my deck.
If you ever need to get a replacement thermostat I highly recommend the Aprilaire 8444 thermostat it's a 1 heat 1 cool non programmable model I have one and have had good luck with it in the 2 years I have had it
THANK YOU!!! very helpful
Great info and video, thanks!
awesome advice... thank you
i’m having this same issue and I can’t find the problem, am I supposed to be getting 24 V from each wire? because I have a yellow and a blue which is my common. my yellow wire has
24V but my blue does not when tested individually. So should they both send 24 V or is it normal to just have the yellow sending 24v ?
Perfect video, dude
That looks super easy. What if it isn't a cut wire. I have no voltage, but also have no cut wire.
In most cases it’s a bad connection or a break in the wires somewhere in the wall. Could also be burnt wire or corrosion.
Still a great video ! Just subscribed
Thanks your video is very informative.
Great clip
Thank you
If this doesn't help check your thermostat, I had this issue and it was just an old thermostat without a digital display so it wasn't immediately obvious
the insulation on that line gets me, otherwise good video
Thanks 🙏
So similar issue but No break in the line. I’m thinking I may have to run a new 24v line
Watch this first to see if it helps 🙂
th-cam.com/video/CkSdvEmw4fg/w-d-xo.html
How Many Gauges And Colors
Are The Low Voltage Wire ???
What Is The Name To Buy In Google ???
Amén.
Great video!
If the Y wire was cut you should not get any voltage between Red and Y wire unless the Y wire was touching off the common which was also cut so that is probably what happened here
Great video thank you
Good video. When you are testing 24VDC you need to set up your Voltmeter to measure DC not AC.
HVAC units use 24V AC
Yes it is typically 24 VAC
Mouse chewed up my contactor wire and when I turned it on first time nothing. I got an old oil furnace with a fan center and I think the short destroyed my transformer relay. Got 120 going into my transformer but no voltage on the red screw...think it's fried...waiting in heat for the new one.
Am actually greatful this one was that obvious and "just a cut wire".
It's those short circuits that look devilish.
Just a minor thing but a cut wire is a open circuit not a short circuit.
thank you for your informative video Sam. I have one question maybe two though, obviously the thermostat gets its 24 volts from the control board at the furnace, correct? And if so What would CAUSE the control board NOT to supply THAT said voltage? thanks again for any more information you can provide.
What if it wasn’t the wire cut? Could have it been transformer from air handler unit?
I’m only getting 12 volts on the low voltage side ? Could it just be bad or further shoot problems
Check the secondary side of the transformer to see if it's putting out 24 volts.
Hi Sam, on mine I have a problem. Heater works, fan works. Low voltage fuse was burned out I changed it and keeps
burning out. When I set the thermostat to cool it burns the fuse. Tested for 24 volts on the capsitor and has no voltage. Disconnected the thermostat cables that go to the contactor and tested them and they do have 24 volts but when I connect them to the contactor it shows nothing. The contactor does have 220 voltage. Any Idea what may be the problem. Thanks. Great videos by the way.
th-cam.com/video/CkSdvEmw4fg/w-d-xo.html
This is a more thorough diagnosis.
My situation is a customer changed the thermostat that had a Nest on it. He put on a T2 Honeywell now I can't get the unit to come on. Contactor stay stuck in. I'm not getting 24 volts at the contactor, I check ed the transformer no 24 volts is coming from that as well. I didn't see any break in the wires but for some reason I'm not getting 24 volts at the contactor. I am stumped. HELP. I thought I had a bad contactor and a bad transformer both of them have been replaced with new ones and the unit still will not come on. 🤷🏾♂️. I checked the fuse on the board at the air handler underneath the house and it is good. Customer stated that the unit worked when the nest thermostat was on after he changed it the unit wouldn't come back on so I've been out there twice and I still can't figure it out. The T2 thermostat is a two heat one cool thermostat. Do you think the batteries in the new thermostat is helping push too much current to the contactor that's making the plunger stick to the contactor? The contactor is a single pole. I enjoy your channel very much it has pulled me out of some jams. Thanks for sharing. #PEACE ✌🏾
My low voltage wire was broken because the lawn mower guys weed wacked it until it fell apart. O_o
Does it matter if you have fan in auto or manual for this job. You said make sure it is in auto ? Thanks for video
There are two fans - one is the air handler that pushes the cold or hot air out to your vents. That is located in the attic. The other fan is on the condenser unit outside. He is indicating that you need to have the thermostat in auto so that the outdoor compressor/condenser/fan assembly gets power. When that gets power the air handler fan which is on the inside comes on as well. You just need to make sure your thermostat is blinking cool and that the set temperature is lower than the actual temperature so that it’ll continue to command 24 V to your contactor/outside unit
No. The auto/on switch on the thermostat applies only to the evaporator fan (indoor blower motor)
The cooling mode switch sends power to the condensing unit outside. It wouldn't have mattered if the fan switch had been in auto or on.
so which one is it guys does auto send power or the cooling switch that sends the power,??? @catfishjones2023
Where do u guyz learn this stuff?!
I tested and only reading 17.4v on it what could be causing this? My problem also contactor doesn't self engage
My blower fan will kick on but compressor will not. If I touch a screwdriver to 24v wire on contractor to the actual plunger metal it will suck the plunger down and kick on compressor. When thermostat hits temp it kicks off. When warms up in house just the blower kicks on and not compressor unless I go out and manually touch the 24v wire contact to plunger metal. One 24 wire comes from a relay looking box above contractor and other is yellow going towards compressor unit. Any ideas? Thanks
Are you getting 24 V across the two wires is the question. If you are I would replace the contactor. In fact I probably just replace the contactor right away. These things go out every few years and it’s cheap insurance and preventative maintenance. They only cost like 20 bucks. They’re easy to replace as well. Just make sure you disconnect the main power but he didn’t go over very well on this video when you’re changing it out
Thanks...........
I fixed my ac, the float switch got activated by excess water in the tube. Weird cause the pan itsself was almost dry
great trouble shooting video thank you
They did not do a good job with isolation on the low voltage wire it shouldn't have cut so easily
I have an AC unit on the roof of my 5th wheel. When you turn it to cool the relay board just clicks. I don’t see a contactor to test. I’ve tested everything and still nothing. I’ve tested the thermostat, condenser, both capacitors and all test good. I’m not sure what else could be the problem. Any ideas? I’m at my wits end here so any help would be appreciated. Thank you.
It's hard to determine without seeing the issue at hand. If you have tested the electrical components... I suspect it may be the board itself. I have had issues where I was at my wits end and after I replaced the board the system fired up. Make sure that you are certain about the contractor. Usually you can trace the it by locating the disconnect or fuse. The disconnect is what sends the 240 volts to the contractor. Follow the disconnect where do the wires lead to? Also I would advise to test just the fan motor. Turn your thermostat to fan on does it run? If it's a furnace board test the heat.. turn it on does it turn on? If those 2 work then you will have a better time isolating the issue as simply the AC. Do you have the safety switch on your door? Does it work? There are many thing that could be causing this issue... let me know if this helps and if you were able to fix the problem. Thanks!
Sam yes this has a furnace on it as well but neither of them work. When I jump power to the fan pin at the thermostat it just clicks but don’t turn on. The only fuse on the relay board is a small 5 amp fuse like a car fuse.. That I know of I’ve tested everything I really know how. I’m not an AC tech I’m just testing wires as I’ve been in the low volt industry for 15 years so I can at least test the wires for shorts etc but that’s about all I know about AC units. I’m just watching videos and reading online manuals to try and fix this. It won’t let me attach a picture.
Who would I call to Repair
Having a simIlar issue where I was losing 24 v going to contactor at a customer's have to go back and re run new low voltage wire since its a 28 year old furnace.
What causes a stuck contactor
Bugs, fused together contacts because of age or pitting I think are the big causes
A good hvac guy woulda found that wire cut into before even pulling the meter out
Finally NON indian explanation
contactor not engaging. What the freak are you messing with the high voltage for??? Dam get with the basics.