Troubleshooting and diagnosing a low voltage short can be stressful. This video will show you how to isolate where the low voltage short is coming from.
Great instruction and demonstration! Super helpful to help isolate the problem area. My issue turned out to be a blown contact on my board as well as some bad corrosion between two jumper lines. Some soldering and terminal cleaning fixed it right up. I also replaced the blower capacitor just for good measure. Toasty again + happy wife. Many thanks!
You saved me a fortune man. I had gone through all of your troubleshooting tips. Capacitors, fuses, blowers, boards switches etc. In the end, all it was was a bad operator who was waiting just short of a minute or maybe seconds. I was not giving the system time to delay and could not figure out why the Emergency heat was kicking on full on gas 112 degrees out of the register. Finally, cool breezes and my cats are no longer giving me the finger because it is 92 degrees in the house...! Cause they can't they could only give me the "claw"....! Thanks so much, I really appreciate it. I just was not patient enough.
found your site last week great presentation the second best i have seen please do one on the circuit board and how you figure out which relay does what etc,, thanks
I'm glad I'm watching these videos because my dad, as damn good as an HVAC installer and technician he is since he has over 33 years experience, is a terrible teacher. I learn by putting my hands on something and doing it myself and he doesn't understand that. And then, in my free time, watching videos on the science and reasoning behind why I have to do what I do.
Thank you! My replacement thermostat was expecting 'C' connection, but my existing thermostat did not have C, but there was wire available, but not connected. I opened the HAVC and connecting the 'C' wire, and connected the new thremostat- but it was not working - I though i blew the fuse. After seeing your video, I realized it is the auto-shutoff safety switch!! once i put the panel back on it started working again. Thank you very much!
I like your videos very informative but also simplistic not stupid but understandable other channels it’s like u need to be 5 years into understand what they are talking about
Can you follow the same steps no matter what furnace you have. I have a goodman GMVC96 and the heat is not engaging. Not sure if the blower is also not working, but guess I can follow these steps there to troubleshoot. Thanks for sharing
I have a couple questions about thermostat wiring on my AC air handling unit. I have a stand alone Comfortmaker air conditioner unit and a separate boiler. Anyway, I was trying to trace a thermostat wire back into my Comfortmaker unit. There is no separate plate like the one you were using to jump the various low voltage wires. Instead, there is a block of wires like the one just to the left of the LED light that goes out when you open the service door. The low voltage thermostat wires are connected to these wires that come out of the block. There are some letters by the wires there where each of them connects into the block. The letters are R, G, T, C, C, and C. The blue thermostat wire I have a question about is connected directly to the R wire on that block. Anyway, what does that wire labeled R control? Is that supposed to get wired as my Rc wire on a thermostat or is it/could it be used as C wire? Also, could I just use a jumper an my Rh to Rc on thermostat and use the blue wire as a C wire to hard wire a thermostat. I am looking to install a programmable thermostat. I am just curious as to what that particular wire does, and if I could wire it that way without damaging anything. I also wanted to say that was a great video! Lots of good information.
Can I ask you. I have a Tempstar Central AC and the fan shuts off at times for no reason, and the White Rogers 1F80 Thermostat keeps Clicking Loudly. The fan usually restarts if I move the fan switch from On to Auto and back to on, the fan turns on again. I have replaced the Thermostat as well as the Blower - Capacitor and Circuit board. It happened again, so I measured the Voltage at the Thermostat between the red power and the green wire during the problem and it showed 8V AC. when I switched the fan switch to Auto and back to on, the fan turned on and the Voltage said 26V AC. Not sure why that would happen. Could you please kindly advise?
Does every furnace have board with a fuse like this one? I hooked up a new thermostat a few months ago and my AC has been running fine. I went to switch on my heat and now it won't turn anything on. I think I may have shorted out my common wire and popped a fuse but I can't find the fuse. I opened up the furnace and took the panel off but no board or fuse. It's a really old system in a trailer
Great video what was the problem shorted contactor coil at condenser causing 3 amp fuse to blow great way to teach and how to test for short on 24 volt side resettable fuse awesome keep 5 on my truck
I have a question. The led light is on and I know I have power to the control board. The heat and the blower are working fine. When cooling called from thermostat the blower comes on but the unit outside does not do anything. I know I am not getting 24 volt at the outside unit contact. I checked and at the control board the Y and R not showing and voltage. The fuse is fine. Why am I not getting 24 volt from Y and R at the control board?
the video was great as far as info about manipulating control boards and thermostats, but had nothing to do with diagnosing a low voltage short, nor did it define what a low voltage short even is. Great video, wrong title. I like the pooper thing, but honestly i dont have those fuses pop very often on me. How often do you actually use the popper and what was the original problem with that unit what where u trying top prove, i feel like the video didnt get to any one specific point. idk
I didnt know if u ohm from the low voltage terminal block u may damage the board. Sends current from meter through it. I think its only if u have wires pulled off though n ohming like R to C or something to see if board itself is the short. U check this very last kinda thing.
I’m not getting 24 volts at the compressor or thermostat but have it on the red wire at the furnace board. Could it be a faulty capacitor on the blower fan inside the furnace? I believe it’s a 10UF.
So i don't normally post on other videos, but i do want to put a thought out there for all techs. 16 yrs in commercial and residential. Now i teach. With that said, I make sure every tech that leaves here when they see this out in the field , C,W.Y, R, G, with one wire on the C and a extra blue wire on the T-stat wire that is not being used. Take that blue wire and connected it with the White wire on the C and on the T-stat put that blue wire on the C terminal of the stat and you never have to worry about batteries again. Easy fix and customer will love you for it and if you do it for free, they gain more trust in you. Cause HVAC techs out there ( yes there still out there) are crooks and we have a hard enough time getting costumers to trust us. Easy fix and takes 2 mins, out of pocket cost 0. Also LiL Popper has saved me many times there about $15 at your supply shop and get both 3 and the 5.
Plastic vice grips on cover interlock, jump red & white on stat terminal ,* use dmm in series with flame rod see signal. * Monitor board sequence via led blinking. All rite now ~∆t
Why would you replace the blower motor capacitor immediately. Should you not check mfd of cap with meter and make sure that it is bad rather than replacing it? 5:27
My blower motor not on at stared up but comes on after burner and the blower will shut off on it's own I tap on side of funace were bord is it comes on trying to feger out wire or bord
Hard to say my friend. I would think a loose wire if hitting the side of furnace is turning it on only because this happen to me before. I had system that uses water to turn on heat (aquatherm). I could not figure out what the problem was. Out of frustration I tool my screwdriver and hit the side of panel and the blower turned on then off. I did it again and sure enough it turned on and off right away. Turned out to be a loose wire. Once I found it the issue was resolved. Hope this helps. The problem with the furnace is you have so many sensors wires etc that you have to be a little more diligent in isolating the cause. Good luck!
@@MoreThanMaintenance thanks for the reply one thing tho the motor comes on only when buners come the blower sould come on before buner I'll look at all wires again thanks Sam have a grate night
If you watch my last posted video the blower motor turned on first... so I'm wondering if it depends on the system. Check out my last video and tell me what you think. Is it possible not every system does the same start up procedure during start cycle? Would be interested to get your feedback as I have had systems where the blower did not turn on right away... possibly a delay 🤔? Thanks for the feedback.
when i jump R & G it just clicks. No blower motor turns on. I have replaced the capacitor. I do not see a reset button on the motor. The fins move freely. I am stumped.
I found this online to help: The NEC says 120V (nominal voltage) +- 5%. This equates to: 126V to 114V. The 5% is to take into account voltage drops. In a residence that has only one main panel (and hence no feeders, only branch circuits), the NEC says +-3%, equating to 123.6V to 116.4, based on a nominal voltage of 120V delivered by the utility. In general, if you are within 5% of 120V, you are fine. This does not take into electric utility company adjustments; although, generally, they will try to deliver a voltage that stepped down equates to 120V by adjusting taps on the transformer. Of course, the delivered voltage will be higher than 120V for some customers (close to the transformer) and lower than 120V to others (away from the transformer), due to the voltage drop in the utility feeders.
@@MoreThanMaintenance yah I was just wondering how many people would not understand. I'm an HVAC tech too and when I first started learning about the voltages that we often use I remember being a little puzzled that they would essentially round the voltages wether its 27v on the board or 243 at the outdoor disconnect
I disconnected the low voltage wire to condenser and let one wire touch the side of the condensing unit... this would cause a short in which the fuse would pop. Hope that helps! Thanks for watching.
Line is the side of the device where the wires from the panel (or other equipment feeding the device) are connected. Load is where any devices that are to be protected by the GFCI device are connected. Most "newer" GFCI devices will not reset if they are not connected probably. GFCI devices use a current transformer (CT), to detect any current differences between the "hot" and "neutral" conductors. The LINE terminals are on one side of the CT, while the LOAD terminals (and the receptacles on the device) are on the other. Hope this helps!
Put your thermostat to off and blower. Does it start? Auto cool starts? Then at this point you have isolated it to a short on your heater upon start up. It can be a variety of issue... wire touching side of furnace. Ground issue. Low voltage wires coming in. It's difficult to answer having not assessed the situation. Check incoming low voltage at furnace board and work your way through process. Watch my latest video on start up furnace procedure I posted 2 days ago.
Low voltage 24 wire that connects to the contactor on condensing unit was touching the side of the condenser causing it to ground. I have a video on my channel where I had this problem. I think it is titled multiple issues fixed. Hope this helps. I have a lot of videos on my channel to help out guys who are new to the industry 👍
after trying to replace a thermostat i knocked out something becuse the furance wont work and only the blower comes on all the time even if its not called for , so here i am
This is soooo fony,SMH,If the fuse is blown than obviously there’s a low voltage short. Showing DIY homeowners is setting them up for mistake that can cause them there lives. PEOPLE CALL A LICENSED TECH TO LOOK AT YOUR EQUIPMENT.
Great instruction and demonstration! Super helpful to help isolate the problem area. My issue turned out to be a blown contact on my board as well as some bad corrosion between two jumper lines. Some soldering and terminal cleaning fixed it right up. I also replaced the blower capacitor just for good measure. Toasty again + happy wife. Many thanks!
You saved me a fortune man. I had gone through all of your troubleshooting tips. Capacitors, fuses, blowers, boards switches etc. In the end, all it was was a bad operator who was waiting just short of a minute or maybe seconds. I was not giving the system time to delay and could not figure out why the Emergency heat was kicking on full on gas 112 degrees out of the register. Finally, cool breezes and my cats are no longer giving me the finger because it is 92 degrees in the house...! Cause they can't they could only give me the "claw"....! Thanks so much, I really appreciate it. I just was not patient enough.
Excellent information, my AC Compressor is on the roof. All of your videos have helped so much.
Another great and informational video sir! Stay hydrated, stay safe and happy HVACing!
Amazing. You just earned another newbie HVAC Tech subscriber. Keep it up Sir. Thx
Excellent video... great job
Very professionally explained.
found your site last week great presentation the second best i have seen please do one on the circuit board and how you figure out which relay does what etc,, thanks
Man one of the best videos ever on this. Thank u so much.
Very helpful information! Thanks for taking the time to share it with us! Sincere regards!
I'm glad I'm watching these videos because my dad, as damn good as an HVAC installer and technician he is since he has over 33 years experience, is a terrible teacher. I learn by putting my hands on something and doing it myself and he doesn't understand that. And then, in my free time, watching videos on the science and reasoning behind why I have to do what I do.
Great video. You are helping a lot of people
Thank you for sharing your knowledge.. Very helpful.
Great lesson. Thanks. Looking forward to more videos
Great vid, very clearly and well explained
Awesome.....great job showing low voltage issues..
Bryan Tyler refrigeration
Love your videos with clear and concise explanations, please keep them coming
Been in the res, industrial field 8 yrs. Good vid def helps when ya dont have to run in and out of the attics etc.
Thank you! My replacement thermostat was expecting 'C' connection, but my existing thermostat did not have C, but there was wire available, but not connected. I opened the HAVC and connecting the 'C' wire, and connected the new thremostat- but it was not working - I though i blew the fuse. After seeing your video, I realized it is the auto-shutoff safety switch!! once i put the panel back on it started working again. Thank you very much!
Very helpful once again!
I like your videos very informative but also simplistic not stupid but understandable other channels it’s like u need to be 5 years into understand what they are talking about
Nice clear, concise video. Good job
Thank you !!!! for your videos very helpful ☺️
Great job, Sam!!!!! You just earned another subscriber.
😀
Hi, very well explained ! Thanks
Good video where show and explain clearly thank you very much to help people, your video help me a lot on the way you explain
Thanks for the video, really appreciate sharing this method of troubleshooting =)
You explain things well.
Allways super bery nice videos ,tanks sam
Good video new technician and definitely will use this method
You know your stuff, good job
Thank you
Very good presentation. Thanks
good explanations.
Dude thanks for the video!👍
Wow awesome troubleshooter.
From tech to tech...Great stuff Sam. Keep these most informative vids...Subscribed 🤘
Can you follow the same steps no matter what furnace you have. I have a goodman GMVC96 and the heat is not engaging. Not sure if the blower is also not working, but guess I can follow these steps there to troubleshoot. Thanks for sharing
Great video bro!!!
Thank you!
Good video!
Nice. Video..sir
I have a couple questions about thermostat wiring on my AC air handling unit. I have a stand alone Comfortmaker air conditioner unit and a separate boiler. Anyway, I was trying to trace a thermostat wire back into my Comfortmaker unit. There is no separate plate like the one you were using to jump the various low voltage wires. Instead, there is a block of wires like the one just to the left of the LED light that goes out when you open the service door. The low voltage thermostat wires are connected to these wires that come out of the block. There are some letters by the wires there where each of them connects into the block. The letters are R, G, T, C, C, and C. The blue thermostat wire I have a question about is connected directly to the R wire on that block. Anyway, what does that wire labeled R control? Is that supposed to get wired as my Rc wire on a thermostat or is it/could it be used as C wire? Also, could I just use a jumper an my Rh to Rc on thermostat and use the blue wire as a C wire to hard wire a thermostat. I am looking to install a programmable thermostat. I am just curious as to what that particular wire does, and if I could wire it that way without damaging anything. I also wanted to say that was a great video! Lots of good information.
Awesome bro thanks
You did good up to the cool test and blown fuse. What was the cool side blown fuse remedy??????
Love the video dude...You got a new subscriber! Lol
Good stuff 😮
Yeah describe this the best I've seen.
Thank you very much :)
Good job
Good vid ...
great video ,can you make one troubleshooting an electric one?
Why did the resettable fuse trip before the main fuse getting melted. Is it faster acting or lower amps trip setting. Thanks Michael
Can I ask you. I have a Tempstar Central AC and the fan shuts off at times for no reason, and the White Rogers 1F80 Thermostat keeps Clicking Loudly. The fan usually restarts if I move the fan switch from On to Auto and back to on, the fan turns on again. I have replaced the Thermostat as well as the Blower - Capacitor and Circuit board. It happened again, so I measured the Voltage at the Thermostat between the red power and the green wire during the problem and it showed 8V AC. when I switched the fan switch to Auto and back to on, the fan turned on and the Voltage said 26V AC. Not sure why that would happen. Could you please kindly advise?
Thanks for all the great video. Question? where did you created a short? outside in the condenser.
I removed one of the 24 low voltage wire from contactor and let it touch the side of the condenser. Hope that helps 😁
@@MoreThanMaintenance thanks
How did you create a short while jumpering from R to Condenser? Y? Did you still have capacitor unplugged on blower motor?
Does every furnace have board with a fuse like this one? I hooked up a new thermostat a few months ago and my AC has been running fine. I went to switch on my heat and now it won't turn anything on. I think I may have shorted out my common wire and popped a fuse but I can't find the fuse. I opened up the furnace and took the panel off but no board or fuse. It's a really old system in a trailer
Great video what was the problem shorted contactor coil at condenser causing 3 amp fuse to blow great way to teach and how to test for short on 24 volt side resettable fuse awesome keep 5 on my truck
I disconnected one of the low voltage wires at the condenser that plug into the contactor and left it touching the side of condenser.
I have a question. The led light is on and I know I have power to the control board. The heat and the blower are working fine. When cooling called from thermostat the blower comes on but the unit outside does not do anything. I know I am not getting 24 volt at the outside unit contact. I checked and at the control board the Y and R not showing and voltage. The fuse is fine. Why am I not getting 24 volt from Y and R at the control board?
when you test are they all 24 volts ?
How did you create the short to allow the 3 amp breaker to pop once you moved your jumper wires to R and Y?
I disconnected 2 low voltage wires from contactor at condenser. Removed one and left it touching the side of panel.
the video was great as far as info about manipulating control boards and thermostats, but had nothing to do with diagnosing a low voltage short, nor did it define what a low voltage short even is. Great video, wrong title. I like the pooper thing, but honestly i dont have those fuses pop very often on me. How often do you actually use the popper and what was the original problem with that unit what where u trying top prove, i feel like the video didnt get to any one specific point. idk
This man is not perfect. Are you? This video was very helpful for me. You can just take the good stuff for you.
I didnt know if u ohm from the low voltage terminal block u may damage the board. Sends current from meter through it. I think its only if u have wires pulled off though n ohming like R to C or something to see if board itself is the short. U check this very last kinda thing.
🌴😎👍 Good video.....
please make more videos simple and direct to the point ps.you are best...
And the jumper work for hit pum to?
I’m not getting 24 volts at the compressor or thermostat but have it on the red wire at the furnace board. Could it be a faulty capacitor on the blower fan inside the furnace? I believe it’s a 10UF.
I've never in my life have seen a COMPRESSOR run on 24 VOLTS. WTF are you talking about? The COMPRESSOR contactor?
@@DominiKing32 yes
@@DominiKing32 You dont gotta be a dick about it
Very useful video! I would like to know where to buy the fuse - one that is demonstrated in the video and the one that we need to replace.
Thos was great but you need more info on the last part the AC troubleshooting
Can you provide me with the proper name for the"" popper "" tester I looked on Amazon and cant find it..Ineed to buy one..please
How n where did you creat the SHORT to show us the little popper works??
So i don't normally post on other videos, but i do want to put a thought out there for all techs. 16 yrs in commercial and residential. Now i teach. With that said, I make sure every tech that leaves here when they see this out in the field , C,W.Y, R, G, with one wire on the C and a extra blue wire on the T-stat wire that is not being used. Take that blue wire and connected it with the White wire on the C and on the T-stat put that blue wire on the C terminal of the stat and you never have to worry about batteries again. Easy fix and customer will love you for it and if you do it for free, they gain more trust in you. Cause HVAC techs out there ( yes there still out there) are crooks and we have a hard enough time getting costumers to trust us. Easy fix and takes 2 mins, out of pocket cost 0.
Also LiL Popper has saved me many times there about $15 at your supply shop and get both 3 and the 5.
Plastic vice grips on cover interlock, jump red & white on stat terminal ,* use dmm in series with flame rod see signal.
* Monitor board sequence via led blinking. All rite now ~∆t
Can we have a link to the popper fuse ?
Why would you replace the blower motor capacitor immediately. Should you not check mfd of cap with meter and make sure that it is bad rather than replacing it? 5:27
If you're tracing down a low voltage short you gotta isolate you tstat wires at your board
My blower motor not on at stared up but comes on after burner and the blower will shut off on it's own I tap on side of funace were bord is it comes on trying to feger out wire or bord
Hard to say my friend. I would think a loose wire if hitting the side of furnace is turning it on only because this happen to me before. I had system that uses water to turn on heat (aquatherm). I could not figure out what the problem was. Out of frustration I tool my screwdriver and hit the side of panel and the blower turned on then off. I did it again and sure enough it turned on and off right away. Turned out to be a loose wire. Once I found it the issue was resolved. Hope this helps. The problem with the furnace is you have so many sensors wires etc that you have to be a little more diligent in isolating the cause. Good luck!
@@MoreThanMaintenance thanks for the reply one thing tho the motor comes on only when buners come the blower sould come on before buner I'll look at all wires again thanks Sam have a grate night
The blower motor does not come on in heating until the flame sensor senses a flame.
If you watch my last posted video the blower motor turned on first... so I'm wondering if it depends on the system. Check out my last video and tell me what you think. Is it possible not every system does the same start up procedure during start cycle? Would be interested to get your feedback as I have had systems where the blower did not turn on right away... possibly a delay 🤔? Thanks for the feedback.
What's the name of the resetting fuse device?
Lily Popper resettable fuse. Hope this helps :)
when i jump R & G it just clicks. No blower motor turns on. I have replaced the capacitor. I do not see a reset button on the motor. The fins move freely. I am stumped.
I wonder how many people got confused when you said "here's my 120v" and your meter read 118v. Lol
I found this online to help:
The NEC says 120V (nominal voltage) +- 5%. This equates to:
126V to 114V. The 5% is to take into account voltage drops. In a residence that has only one main panel (and hence no feeders, only branch circuits), the NEC says +-3%, equating to 123.6V to 116.4, based on a nominal voltage of 120V delivered by the utility. In general, if you are within 5% of 120V, you are fine.
This does not take into electric utility company adjustments; although, generally, they will try to deliver a voltage that stepped down equates to 120V by adjusting taps on the transformer. Of course, the delivered voltage will be higher than 120V for some customers (close to the transformer) and lower than 120V to others (away from the transformer), due to the voltage drop in the utility feeders.
@@MoreThanMaintenance yah I was just wondering how many people would not understand. I'm an HVAC tech too and when I first started learning about the voltages that we often use I remember being a little puzzled that they would essentially round the voltages wether its 27v on the board or 243 at the outdoor disconnect
how did you created a short?
Removed one of the low voltage wires from the contactor at condenser and let it touch the side of the condenser. Hope that helps. Thanks for watching!
where is the short when you are testing the Y and R jumped terminals?
It was by my low voltage wires at the condenser unit outside. I have a video posted on my channel if you need to review it. Thanks for watching!
At the end of video u said u purposely caused a short....what did u do to cause it to Trip...
I disconnected the low voltage wire to condenser and let one wire touch the side of the condensing unit... this would cause a short in which the fuse would pop. Hope that helps! Thanks for watching.
Could you add to this and explain the Line/Load. Thanks
Line is the side of the device where the wires from the panel (or other equipment feeding the device) are connected. Load is where any devices that are to be protected by the GFCI device are connected.
Most "newer" GFCI devices will not reset if they are not connected probably.
GFCI devices use a current transformer (CT), to detect any current differences between the "hot" and "neutral" conductors. The LINE terminals are on one side of the CT, while the LOAD terminals (and the receptacles on the device) are on the other.
Hope this helps!
In AC units, the internal electrical Components would be the load and the disconnect would be the line? Thanks
ruclips.net/video/VH4VxlkprGM/видео.html
you can buy one or rob it off an old carrier pack unit or lennox furnace if its being replaced.
Not to mention crawl spaces
What did you do to make a short at the condensing unit
I removed one of the low voltage wires going to the contractor on the condensing unit and let it touch the side of the condenser.
But how you solve the problem
Greetings,But in the end it was damaged
My furnace works on cool and auto fan, but once I call for heat it pops right away. Where do I start from there.. A NOVICE
Put your thermostat to off and blower. Does it start? Auto cool starts? Then at this point you have isolated it to a short on your heater upon start up. It can be a variety of issue... wire touching side of furnace. Ground issue. Low voltage wires coming in. It's difficult to answer having not assessed the situation. Check incoming low voltage at furnace board and work your way through process. Watch my latest video on start up furnace procedure I posted 2 days ago.
How do you fix the short? Lol
Run a new Tstat wire or if there’s extra wires, use a different color
Noobie apprentice here. Why did the resettable fuse pop when the condenser was shorted?
Low voltage 24 wire that connects to the contactor on condensing unit was touching the side of the condenser causing it to ground. I have a video on my channel where I had this problem. I think it is titled multiple issues fixed. Hope this helps. I have a lot of videos on my channel to help out guys who are new to the industry 👍
What about how to fix the diagnosed low voltage short?. Mine shorted on the eve of 4th July $%$@!
after trying to replace a thermostat i knocked out something becuse the furance wont work and only the blower comes on all the time even if its not called for , so here i am
The difficulty of this comes from a certain kind of costumer who always stands over you while you're working and their house smells of burnt curry 😒
Mr Oblige
Or sometimes smells like chitlins 😂😂😂😂
@@user-ge6ce2lu1v Or wet dog
Moe Bunny Paul Or urine.
All shorts are low voltage...high current 😁
Nope, that is why we buy cap check meters. Stop the guesswork.
This is soooo fony,SMH,If the fuse is blown than obviously there’s a low voltage short. Showing DIY homeowners is setting them up for mistake that can cause them there lives. PEOPLE CALL A LICENSED TECH TO LOOK AT YOUR EQUIPMENT.