Control board fuse blowing out

Old 07-23-12, 01:39 PM
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Control board fuse blowing out

The control board on my inside unit (Comfortmaker) keeps blowing out the 5 amp fuse. What things could cause this? The unit is 20+ years old.

I made the mistake of swapping it out with a 10 amp fuse out of desperation and ended up blowing out the board and the 240->24vac transformer. I've replaced both and now back to the original problem where every day or two it blows out the fuse.

One new strangeness though is that with the new board the fan is constantly on. I tripple checked the wiring and it's the same as the old board. Any idea on this part would be appreciated as well.
Old 07-23-12, 04:49 PM
Tolyn Ironhand's Avatar
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Look for some low voltage wires in/on the inside and outside unit that is shorting to ground.

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