Have HVAC Questions? Ask an HVAC Expert for Answers
Yes, it does.
Ok, I'm at the board, but not sure exactly which terminals those are. What letters correspond with those?
Follow fan wires to board, One will go to terminal marked COOL. (Probably black). Then white will go to one of the terminals marked n (Neutral).Between those 2 wires we should be getting 120v
I'm not getting a reading. Not sure I'm getting good contact. Can I remove the wires from the board, or do they have to be connected?
I'm getting nothing. I double checked against a nearby wall outlet to confirm my multimeter is working.
Ok. Now gently tap on the small black relay boxes integrated into the control board and see if we get a reading. Often those little relays will stick open or closed.
I unplugged the common and cool leads, tapped every black box, and still get no reading.
Ok, that's what I needed to know. I'll get the new one tomorrow. Thanks.
Just for clarification, when I was doing these tests the furnace had power, but the system was not running. Is that how it should be while checking the terminals like I was doing?
Well that changes things. My thermostat was set to off. i will set it to cool and go check the terminals again.
Do I want to drop the thermostat setting so that the blower is actually running while testing, or just have it set to cool?
Well now we have a different ballgame. With the system actively running, the common and cool terminals are showing 119.5v.
It's working, it's just a question of how long it will run before the system frosts over. The blower and everything will come on initially, but then the blower shuts off leaving the rest of the system trying to cool the air. Soon the lines (inside and outside) frost over.
I thought of that. I ran downstairs as soon as the blower quit. The rest of the system was still trying to cool. I got no reading on my multimeter.
Ok. I will proceed as I had planned in the morning. Thanks again.
New circuit board installed earlier this morning. So far the system is working well. Hopefully it will prove to be finally fixed. Thank you for your assistance.