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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a weathertec rooftop heating and cooling system that

Customer Question

I have a weathertec rooftop heating and cooling system that the fan will not shutdown
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.


It is most likely burnt contacts on the fan relay, or a bad printed circuit board that is attached to.

OR...the thermostat is set to FAN ON, instead of Fan Auto.

Tell me about how old the system is please. and the full model number on the units ID tag.

Please attach a well focused, close up photo of the wiring diagram glued inside the service panel,you can use the paper clip-icon at the right end of the toolbar at the top of this dialog box,Include a picture of the thermostat wire connections to the printed circuit board in the same area.

If there is no paper clip-icon, look for the '+attach files' link at left of your send button.

I can mark it up with trouble shooting instructions. You will need a multi meter ($30 at a hardware store) and some experience working with appliances, let me know a lot about your skill sets in those regards.

If none of this in your skill sets, tell me which direction you are from the center of the nearest city and I will look for a few well rated service outfits in your area.

Customer: replied 1 year ago.
No model number worn off. No paper work inside the system. Thank you I will try cleaning all electronic contacts. If that fails guess I will call a pro. Thanks again
Expert:  Phil replied 1 year ago.

Hello again, on systems built since 1987 or so, the relays are soldered into the printed circuit cards and the contacts cannot be accessed.. in those case you need a new printed circuit card.

Prior to spending that money however, you can try removing the wire from G terminal of the thermostat, if that stops the fan, then its a thermostat problem. That will be an easy check you can do,

The other tests get a lot more involved,

Regarding calling in a field tech..

Some of these are absolutely superb... maybe 20% to 30% will do a good job for you, if you have experience with such a company that would be a good way to go... in not, the 40% towards the bottom of the scale can be a bit dicy.

If you need help finding a well rated company in your area, tell me which direction you are from the center of the nearest town or city and will see if I can find some well rated service for you.

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