Code 31 keeps coming up. I made sure the intake and exsast were not blocked. When I tape the presher valve and turn the power off and back on it works fine. Should I just replace the valve or call a pro. Its happen once last year and I called a pro and of course it worked fine wile he was here 160$ wasted. This year its happening more often.

You can try these suggestions.

Why Is My Payne Furnace Showing Error Code 31?

Put a meter on the pressure valve, and check the vacuum lines

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Expert: Tim H. replied 3 years ago.
No, the vacuum lines need to be attached for it to work correctly. The board will look for an open pressure switch prior to starting and then as inducer comes up to speed will look for the switch to be closed. However, if there is water backing up in the collector box, and exhaust, this will affect operation of switch closing properly.
Page 3 of this manual shows the condensate trap and hoses located in the blower compartment. These need to be taken apart and rinsed out with hot water.

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