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HVAC Guru
HVAC Guru, HVAC TECH
Category: HVAC
Satisfied Customers: 13967
Experience:  15yrs in the HVAC industry with certificates and degrees.
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I also have a P374-1800 No power/lights on screen...Had a

Customer Question

I also have a P374-1800
No power/lights on screen...Had a butch of people over not sure if someone pressed something or it is just not working...
Submitted: 1 year ago.
Category: HVAC
Expert:  HVAC Guru replied 1 year ago.

Hello and thanks for using this service, if you have been waiting do not worry or get upset I am just one of the techs on here and I try to get to as many customers as I can and I just picked up your question now. Please give me time to respond as typing, researching and adding links takes me time to do so please be patient and often I will ask you questions to narrow down the issue to get is diagnosed correctly.

You likely blew the fuse on the board in your furnace. You need to go to the furnace or airhandler and remove the panels to get at the main board inside the unit. There is a 3-5amp slot fuse on the board. Take that off and inspect it to see if it is blown, replace that if so and your thermostat should work fine again.

We are on the honor system for our time, all I ask is please rate my service using the STAR RATING LINK on your page before you leave. If you are not happy with the service please let me know before leaving a negative rating. This is the only way I am paid or credited through the site for my time. This will also allow you to get directly back to me for FREE follow up questions and tips are greatly appreciated! Thanks

Customer: replied 1 year ago.
But I was using my air conditioner furnace is off
Expert:  HVAC Guru replied 1 year ago.

Yes but the board that controls the AC is still in the furnace....it is the board that controls both.