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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Outside fan runs continuously whenever there is wet weather

Customer Question

Outside fan runs continuously whenever there is wet weather
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, you have done the most sensible thing, the odds are high that the printed circuit board is bad.

You can try a heat stress test.

Use a hair drier to slowly warm the printed circuit card up to120For a bit warmer, but not over 140F... if there is any change in the error codes or other furnace behavior... the card has a cracked micro circuit that opens and closes as the card expands and contracts... that proves a bad printed circuit card.

No change however does not prove the card is good however... but a change proves the card is definitely bad.

We can go from there.

Customer: replied 1 year ago.
Phil,Thank you good sir, firing up the blow dryer as we speak.Thanks very muchMark
Expert:  Phil replied 1 year ago.

Let me know how it goes, repeat the test if you need to.