From Problem to Solution: HVAC Contactor Troubleshooting and Replacement

In this video I explain step by step how to troubleshoot and replace your HVAC contactor. It's a very easy job to figure out if that's your problem or not and it's just as easy to replace it. I also give some tips as to what else could be wrong when you have a unit that won't come on.

[@themeat5053]

Thanks, Rudy. You're making this easy for us.

[@TheHomeImprovementChannel]

You're welcome! Thanks for the feedback... 😀

[@alwaysrockn2009]

Good video. It was helpful explaining the single vs dial pole. I’ll be replacing mine along with a new Capacitor in a few days.

[@TheHomeImprovementChannel]

Excellent! Thank you for the feedback... 😀

[@davidcolwell1577]

Very good video! Well explained and clear. Thank you.

[@TheHomeImprovementChannel]

TYSM! 😀

[@stingk5295]

Great Video!

[@TheHomeImprovementChannel]

Thanks for the great feedback... 😊

[@sijahwmvaj]

This is super helpful just the thing i needed

[@TheHomeImprovementChannel]

That's awesome! SO glad to help... 😊

[@haint7709]

Nice video. Ta!

[@TheHomeImprovementChannel]

TYSM! I really appreciate it... 😊

[@dontworrybehappy4379]

Just to be clear you were referencing the 240v at the contractor but you said to shut off all the power in the beginning. ???

[@TheHomeImprovementChannel]

Yes I always recommend shutting off the power before beginning a project because I don't know who's comfortable working with power and who's not... if that makes sense. However there are times that you have to turn the power back on to test stuff and that's where someone not comfortable shouldn't attempt to do that...

[@HD-bh8yr]

Nice video. I am not a prof in this area. But I just installed a new contactor, the old was rusted and broken, but the plunger did not pull in when I turned on the thermostat. I am sure I installed correctly because quite simple, took pictures, and when manually pushed in the fan/compressor run. It seems I can only see the reading of 26v on my volt meter of the control wires from the inside transformer only when the plunger get sucked in otherwise 0. My question is how do you test if the control wires actually get 24v without connect to a contactor? Thanks

[@TheHomeImprovementChannel]

HI, if you have 26vac between the blue or "C" wire (Could be black) and the red wire (I'm assuming you're working on a heat pump) then your transformer in the air handler is in good shape. When the T-stat is calling for heat or ac the yellow wire should be energized coming into the unit. This yellow wire should be the one to energize the contractor. Depending on what unit you have, the orange reversing valve may or may not be energized. Most of the time it's de-energized in heat mode. If you have nothing on yellow coming into the unit, I'd check out the t-stat... Between yellow and common... Hope that helps.

[@nitadavenport3964]

What contractor did you replace that with I've been looking all over for a contractor I can't find one with the exact numbers and mine is just like the one you replaced

[@TheHomeImprovementChannel]

The exact numbers may not be super important. The voltage is usually 24 volts and you'll want one that's the same amperage. Depending how big the unit is... Also if the original was a single pole or double pole. The one in the video I just got from Amazon.. Hope that helps.

[@georgeterbush2976]

Can you explain what the symptoms were before replacing the contactor? Was the outside unit completely dead or could you hear the compressor running but no fan spinning? Thanks.

[@TheHomeImprovementChannel]

HI, in this particular case I replaced it for preventative maintenance... Usually when the contactor goes bad you might have a little humming noise and the unit isn't running... It'll affect the whole unit compressor and fan. The best bet is only if you're comfortable with working with electric take a volt meter and see if you've got your 240 VAC coming in from the house but it's not on the output of the contactor. If you see this, make sure you have the low voltage 24VAC on the coil of the contactor.. If it's not there then it's probably not the contactor but the problem is somewhere else of which are many possibilities. Hope that helps.

[@georgeterbush2976]

@@TheHomeImprovementChannel Thank you for the tips. That helped. The 24VAC was at the coil of the contactor and it pulled in the contactor contacts which turned on the compressor and fan. The problem I am having is the unit is not getting out of defrost mode. It's possible the compressor coils are not getting hot enough (80 degrees) to open that little defrost sensor clamped on the compressor coil. I'm not an HVAC guy. Just a homeowner learning what I can on KZbin. Thanks for your channel!

[@TheHomeImprovementChannel]

Yes it could be ... I've also seen the circuit board inside the outdoor unit fail.. That does control the defrost as well... If you search KZbin for possibilities on defrost problems, you should be able to find a video that someone did outlining all the possibilities. That board will send out a signal to the reversing valve to switch it into ac mode which sounds wrong, but it actually is able to heat up the coils that way... One other thing, it's a long shot but if you're stuck in defrost there's a possibility the reversing valve could be the culprit. @@georgeterbush2976​

[@georgeterbush2976]

@@TheHomeImprovementChannel Thanks again for the suggestions. It was warmer yesterday so I turned the heat pump on and it was in defrost mode for a few minutes, then Whosh, the reverse valve energized and the fan started spinning again in normal heating mode! I'll keep an eye on it. Thank you.

[@TheHomeImprovementChannel]

Oh cool! If it turns out to be an intermittent problem, I ran into that once and it was a major pain! It turned out to be the defrost board... @@georgeterbush2976

[@molifehacks5258]

Could a bad contactor keep blowing a fuse at the disconnect?

[@TheHomeImprovementChannel]

HI... It's doubtful. The best thing to do is isolate things from the circuit until the fuse stops blowing. For example if you suspect the contactor you can disconnect the output of it leaving the low voltage connected so it'll engage. If the fuse stops blowing you'll have to move on to the next thing. I would find out which wires are coming from the compressor and disconnect those and see if it's coming from that. Obviously if you're not comfortable working around electrical things then don't try it, but if you are, that would be my strategy..

[@patfromamboy]

I used to work everything hot. I replaced all of the light switches and outlets in my parent’s house energized. It was more fun that way. I didn’t have any problems. I used to work on everything hot at the power company to keep everything energized too. I just got used to it. It prevents any mistakes if I’m wrong about something being de energized too. I treat everything as being hot. I don’t recommend it for normal people though.

[@TheHomeImprovementChannel]

Oh yea, i've done that too.... But it's like you said, I can't recommend it for someone else.. 😎😎

[@kennethhinckley6578]

Ridiculous statement.

[@Whyusemyname]

Same here until I shocked myself. Now I take the extra 2 minutes to kill power and test everything. Much less stressful

[@captaincat40]

You brave enough to try that on 460 volt 3 phase? 😅

[@cheiftribe8746]

WOW very impressive Mr. Electrical man!

[@luiscarranza3543]

Yup problem solved thank you just rest the contactor and it kicked right on and also there was a rat nest 🪹 😂

[@TheHomeImprovementChannel]

Oh yea they'll build a nest in there. Could be mice, they like doing stuff like that. Glad you got it going again... 😊