😂😂 was looking for a video that showed how to measure the voltage with the transformer still in place, since many recommended videos have the setup on a plywood display. And sure enough, you hitting the switch made me remember I need to push the lock out switch closed to get voltage to the transformer. 😂😂
Just want to say your video fixed my problem. Just replaced the control board and transformer but still didn’t work. I left the cover off incase I needed to do something else so the safety switch was still on. Put the cover on and now it’s working like normal. Definitely a duho moment.
I just moved into a new home and want to instal an ecobee. I went to the transformer and only have 1 segmenet of 24v through the RED secondary, the GREEN secondary is grounded and doesnt have constant 24v. The GREEN wire is connected to my BLUE C wire. the result is that Im not getting constant power to my thermostat C wire. Is this a wiring problem?
This morning I woke up with the heater running but our Honeywell wifi thermostat screen was blank so I used my multimeter to try and get a reading at the wall but the voltage came back as 0. I went up to my attic to check the condenser drain pipes, which doesn't have a safe-t valve feature, but I didn't see any clogs that would trip the power to the thermostat. The pipe was clogged a little and I cleared it but it wasn't at a point where it was backing up to trigger any overflow issues. Then I popped open the furnace to check the fuse and it wasn't blown. The low voltage power-in from the transformer to the board gave a reading of 17 and the board was flashing green with the heater still running fine. I tried to take a voltage reading for the wiring going to my condenser unit but it only gave a 1.3 reading. Would greatly appreciate some insight and suggestions, thank you!
bro that black wire fr the transformer is going to PR1 or SPEARS 1,2,3 ? and also the white wire is going to SPEARS 1,2,3 or ? bottom line im trying to connect those wire the black and white im not sure and I didn't take a pic .......thank u for understanding
When I test my transformer, when it is not connected, the meter reads resistance on the high side and the low side. Like 18 ohms on the high side and 1.6 ohms on the low side. The circuit board has no power when I connect the transformer. I've got 120 v at the lines that go into the circuit board. And 120 v coming out of the board through the wires that go to the high side of the transformer when I push the door switch, but no voltage coming out the low side of the transformer. (And no red light) So is the transformer bad, even though there is resistance when the transformer is unplugged?
Make a cheater cord and connect it to the transformer primary. Plug it in and check for 24 v on the secondary. Simple. Using an ohm meter properly will give you a reading of OL if the winding is bad and reading if it is good. The secondary winding is far more robust and is generally still good even when the primary winding is shorted out. You must not hold the test probes with your hingers when checking as this may result in a false reading.
i did some testing with my multimeter. i have no voltage at the thermostat terminals. in the furnance i have no voltage on the terminals that say R W Y G etc. either. my led light on the furnace is not lit at all. i have voltage from the switch to the board. (120v). the fuse doesnt seem to be burnt. what could the possible problem and solution be?
I thought I had a bad control board...since I had no tripped breaker, no status light, good fuse on bird and no power at L1 and L2 (Carrier 80), installed new board and same issue. It seems I’m not getting power at all to the furnace...tested breaker with meter - 120 on each breaker, tested for 120 at the service disconnect switch and not getting anything - since the breaker is testing good...could the power switch for the furnace be bad?
No status light indicates to me loss of power to board. Check incoming power... are you getting 120 volts? If you are I would suspect the safety switch located on the panel door. Let me know how it goes!
Sam Thanks for the quick reply Sam, we’ll...the power issue turned out to be a mislabeled breaker that looked like it was on but was off. Got power to the board now...but when it turns on (cool, fan ON) the blower motor is making a whining sound as it ‘attempts’ to start...then shuts off. I swapped the capacitor with my other upstairs unit of the same model and it’s still doing the same thing. I can turn the wheel freely and don’t currently feel any play. I’m about to pull the blower motor from the working unit and install it in the non-working unit to see if that resolves the issue...does that make sense or would you suggest I go another direction?
Ok I'm a little confused...the low voltage wires coming from the transformer are hooked into the circuit board, I get that. But why are the 120v wires also hooked into the board? Aren't those the wires that are supposed to supply power to the transformer? If both the 120v wires AND the 24v wires are tied into the circuit board, how is the transformer being powered?
I have a question sir. My ac unit is not working. The thermostat is turned off and has no power coming to it. I checked the breaker box and its fine. I checked the 5 amp fuse on the air handler control board and it is fine. I am getting power everywhere except the control board and the output of the transformer. I have 240 going into the transformer but less than 1 volt on the output which is supposed to be 24 volts. I checked my contactor and it does have power. When I press the button on the contactor the AC unit will turn on. So I'm not sure if it could be a bad transformer or a bad control board or something else?? Your advice would be greatly appreciated! Thanks!
@@jaywallace9800 thanks. I'm currently working on my trane unit. I have no power going out of the transformer. Took that off there is a brunt spot.. hopefully that will fix it. I got 25° last night.
