Furnace on the fritz

[TLO]

Last night as I got home from work I noticed my home was cooler than usual. I checked the thermostat, saw it was calling for heat, and headed to the furnace itself to see if I could figure anything out.

Anyway, I noticed that the furnace was trying to kick on, but would shut itself down after about 5-8 seconds. I noticed a light on the circuit board that would come on as the furnace was trying to start up, but then would turn off like the system was cutting power.

Anyone have any thoughts on what may be wrong?

[Chief Roundup]

Originally Posted by myselff77

Hey HVAC experts… AC is on the fritz and spent the day troubleshooting, but couldn’t figure anything exact out. Anything I might be overlooking before calling some HVAC Company on Monday?

Overall issue: Nest thermostat was showing a E183 error indicating a problem with the Y wire. Also outside unit not turning on.

I thought it might be the contactor. Went to outside unit. It would manually turn on fine when manually pushed. Then I checked for 24v coming in and got nothing. So I’m thinking the contactor may be fine and it just is t receiving voltage to engage.

I checked the control board with a multimeter. 24v properly coming into the board from the transformer. Again nothing at Y. I could see voltage properly come through green and white when thermostat called for heat or the fan. The control board LED is blinking a continuous slow steady red indicating no problem. I tried jumping the red and yellow to see if that would kick on the outside unit, but no luck.

So I can’t figure it out. Faulty Y wire somewhere? Just seems strange I can’t see voltage on the Y coming in from the thermostat, but also don’t see anything to the outside unit when jumping either. Anything additional I should look at?

So you are saying you have 24v at the outdoor unit at the control board? If you measure voltage by putting one lead on the red wire and one lead to the frame or ground you have 24v?
Or are you saying that you have 24v inside but not at the outdoor unit? If you do not have 24 volts to the outdoor unit it will not run and you probably have a bad thermostat wire.
The wire that is connected to Y is your call for cooling if you have nothing there at the outdoor unit, condenser, then there is no signal from the air handler to make the outdoor unit operate.

[Boise_Chief]

Is the blower turning on when it calls for heat or cool.
I think you should have 24v at the thermostat on the red wire? Then the tstat carries/switches over to the yellow. Will heat work correctly?

[myselff77]

Originally Posted by Chief Roundup

So you are saying you have 24v at the outdoor unit at the control board? If you measure voltage by putting one lead on the red wire and one lead to the frame or ground you have 24v?
Or are you saying that you have 24v inside but not at the outdoor unit? If you do not have 24 volts to the outdoor unit it will not run and you probably have a bad thermostat wire.
The wire that is connected to Y is your call for cooling if you have nothing there at the outdoor unit, condenser, then there is no signal from the air handler to make the outdoor unit operate.

The latter is correct. I do not have 24v outside. I think you are correct on a faulty y wire, but I can’t figure out if it’s between the thermostat and control board or between the control board and outside unit (or somehow both)?

[myselff77]

Originally Posted by Boise_Chief

Is the blower turning on when it calls for heat or cool.
I think you should have 24v at the thermostat on the red wire? Then the tstat carries/switches over to the yellow. Will heat work correctly?

Yes I think heat and fan by itself are working correctly. The blower in the furnace does appear to turn on though nothing outside.

[Boise_Chief]

Check your wires that run from the furnace to the contactor. If you have 24v from the furnace but not at the contactor then the wire is broken or chewed etc. I had that happen to me. Mouse chewed them and they shorted together. Still whole but grounded out

[Peter Gibbons]

I’ve heard that when your home needs a little repair you can call 3-2-1-2-2-7-7 anytime night or day. Have you tried this? If that doesn’t work, setting fire to the place to claim the insurance may be your only other option.

[myselff77]

I’ll be calling a HVAC company on Monday. I tried swapping out the nest thermostat for the one that was previously there Interestingly enough, I was finally reading 24v coming to the control board’s Y terminal. However, it also popped the transformer a moment later so that definitely needs to be replaced now too in addition to what I assume is rewiring the whole thing. Will be interesting to see what this winds up costing.

[scho63]

Get some ball bearings. It's all ball bearings today.

[Fish]

Originally Posted by Boise_Chief

It could be your board but what you are describing is that the furnace isn't seeing airflow from your combustion motor. You have a small motor just inside. Is it turning on. It's fairly obvious. Also you have a little pot that has a small rubber hose tan or clear. Take one end off lightly suck and blow a few times. Replace that end and do the same with the other end. Then try turning it back on

So, this just happened to my furnace yesterday. This post was the fix.

May I mail you a cheeseburger, friend?

[Boise_Chief]

Originally Posted by Fish

So, this just happened to my furnace yesterday. This post was the fix.

May I mail you a cheeseburger, friend?

Beer is preferred.

[Boise_Chief]

This actually was a great thing to see on CP at this moment. We are cleaning out my parents house, they both passed in dec and Jan. Gave me a chuckle and and moment of respite. Thx

[neech]

Originally Posted by Boise_Chief

This actually was a great thing to see on CP at this moment. We are cleaning out my parents house, they both passed in dec and Jan. Gave me a chuckle and and moment of respite. Thx

My parents passed away within 3 weeks of each other. It was kind of a shock to us. Sorry about your folks Boise.

[Jewish Rabbi]

Originally Posted by Boise_Chief

This actually was a great thing to see on CP at this moment. We are cleaning out my parents house, they both passed in dec and Jan. Gave me a chuckle and and moment of respite. Thx

So do you want the cheeseburger or can he send it to me?

[Boise_Chief]

You're good rabbi enjoy the burger!

[Jewish Rabbi]

Originally Posted by Boise_Chief

You're good rabbi enjoy the burger!

Thanks buddy!