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Moe Jones Moe Jones is offline
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Default Goodman HVAC system control problem- blown transformer

dm440c wrote:
Hi, we have a 4 year old house and the upstairs AC thermostat
suddenly lost it's display. I switched the thermostat with the
downstairs one and the problem stayed with the upstairs unit. I
received a tip that the 240v to 24v transformer might be the problem,
so I went up to the attic where the air handler is and tested the
leads on the transformer... sure enough, 240v in is OK but nothing is
coming out on the 24v side. So, I got a replacement transformer and
wired things back up. The display came back on, the unit switched on
and started blowing through the vents and I thought i had fixed it.

BUT about 5 minutes later i went up to check on it and the display
had gone back out, so something is tearing up the transformers. I'm
not an electrical engineer, but I can't figure out what would burn up
a transformer without tripping the main breaker. Any ideas?


When you replace the transformer again this time wire a inline fuse from the
transformer so when it shorts out again it will blow the fuse and not
destroy the transformer. Where you buy the transformer they should be able
to tell you what size fuse you will need. Then you can start to find what is
blowing your fuse. It does sound like when the A/C starts it blows then I
would check the wiring going to your A/C outdoors. You wouldn't believe how
many times I have seen a weed wackier had cut into the control wiring.
Good Luck.
--
Moe Jones
http://www.MoeJones.info