Ruud Furnace ugra-09ezajs

[fullerdan27]

Issue is keeps poping 3 amp fuse on the bourd. Acoil is clean and so is outside unit. ac works for about 45 mins then blows the fuse. Also new bourd is 2 months old. I know its a 24 volt issue some where. also theremostat is new. any help. would be great

[JWWebster]

Might be thermostat wiring getting brittle?

[jumptrout51]

What was the issue with the original board?

[fullerdan27]

It was doing the same thing witht the old bourd as well

[JWWebster]

Thermostat wire ok?

[jumptrout51]

Not many components to verify here.
The transformer,the indoor fan relay and the contactor on the condnser.
Whenever the fuse blows,one of these components should be hot to the touch.
Check the wiring on all these parts and or replace the wires.
If the fuse consistently blows,a amp meter might help narrow down the over-amping part.

[Repair-man]

I had one doing this  during the summer, and ultimately discovered the LV thermostat wire going to the condenser to be pinched where it comes out of the  brick wall. This particular house  had the LV wires run alongside the HV circuit in the same conduit to the unit, and both passed thru a shut-off box on the wall near the unit. I got lucky and found the pinch after replacing the fuse several times. The odd thing was, the unit had been installed for 7 years before this showed up...
Cut out the flattened section and it worked fine.

[fullerdan27]

Thanks everyone for there replys. Found out it was a short in the 24 contactor over heating. Replace and issue resolved.

[JWWebster]

Wow that is unusual. Mostly the coil dies. A shorted coil is weird to say the least.
The coil was getting hot and going to ground. Wild. Glad you could get er goin.