I have a Goodman electric unit for 15 years. Had issue coming back from vacation I do have a nest thermostat that said e73 no power to rc. Check voltage at breaker and transformer on secondary side wasn’t getting 24v. Even when I used straight wire to primary 240 and nothing connected on secondary hook meter no 24v. Bought a new breaker and transformer same thing. Don’t understand what I’m missing. Correction 7 to 8v on secondary
No power on 24v transformer
- Thread starter Debonaire
- Start date
Help Support House Repair Talk:
So right at the power in (primary) on the transformer you are measuring 120V and nothing on the secondary side that should be 24V. You then replaced both the breaker and the transformer still read 120V primary and zero secondary or 7-8V secondary.
Is that with the wires disconnected on the secondary?
Can you bench test the transformer?
Not sure why you changed the breaker?
Is that with the wires disconnected on the secondary?
Can you bench test the transformer?
Not sure why you changed the breaker?
Correct that’s without wire leads on secondary, been messing with since Tuesday it worked overnight Tuesday after changing transformer shut off that morning. That when I notice I didn’t have 24v turned main breaker off for 10 minutes the breaker back on it ran till it satisfied. Never have been able to start back up. I pushed in the contacted on outside condenser to make sure compressor was good and it’s good I can hear it start up
Sounds like if you are measuring that low voltage on the new transformer after it worked for a while and stopped then it also went bad.
I don’t know if something down stream on the secondary is shorting causing the transformer to go bad or you just got a bad one.
I think I would try another and if it fails after a short time I would start looking for that cause.
I don’t know if something down stream on the secondary is shorting causing the transformer to go bad or you just got a bad one.
I think I would try another and if it fails after a short time I would start looking for that cause.
Then you have a bad transformer or a bad meter or meter set up wrong.
Those are my thoughts. I have bought electronics before that didn't work correctly.
Maybe someone else will have some thoughts.
Those are my thoughts. I have bought electronics before that didn't work correctly.
Maybe someone else will have some thoughts.
If it failed the bench test then again, you have a new bad transformer. Did you bench test before installing (was it good to start and now bad?). At first I thought you heat pump was having startup trouble and faults out after X many attempts, which may cut power to the transformer. Resetting the breaker effectively resets the fault on the unit so check it after reset and before fault lockout.
Found the problem the main breaker when I was reading it earlier this week when it was working and bench checked it was fine. But when it tripped never went back to it I just reset it. I still was reading 120 from ground to each pole But not across on pole side where I suppose to get 240 I was getting zero. And when I took it out to bench test for continuity one side was no good
DesertRider
Active Member
Golly guys, that was a hard post to follow... still not sure exactly what transpired, but glad you found the problem
