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My furnace wasn't working so my ran the test and it showed "reverse polarity" how can that be we have had a running furnace for 12 yrs and we have never touched it. Anyway he bought a new control board and installed it and it still didn'

Post created: 2013-04-13 Type of Equipment: Furnace Views: 174

This question was created on the page: https://www.furnacecompare.com/furnaces/bryant/340mav.html.

On 2013-04-14 JB wrote:

Generally this is a sign of a bad control board. Perhaps there is an issue with the transformer or maybe there is a problem with the new control board. I have also read that if there is fluctuation in the power coming into the house it can fry a mother board so it could be something to do with the source and not the furnace.

This is a tough one to provide advice on because it really does require a certified HVAC tech to be on the scene and run some diagnostics. Many furnaces have an error code, which is either a couple of blinking lights are an LED display, that advices to switch two wires to check polarity, but this can be a dangerous thing to do and is not recommended.

Sorry to not be of more help.

To keep legal happy, let me just say that I am not an HVAC contractor, and you should never even look at your furnace without having a qualified, liability accepting HVAC contractor present.  To keep sales happy, let me just say that you can find an HVAC contractor that's happy to take your money here: http://www.furnacecompare.com/perl/find_contractors.pl.

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