I have a varitrave vpef vav box with a ucm4.2 board. This is a 460v 3 phase unit. On a call for heat the blower will come on, make the air switch and and go to the contactor that beings on the heat strips. This is a single stage unit. The orange wire(com/grnd) is not making a ground so the contactor won't pull in. The back of the ucm board looks good, no burnt connections. I havn't had a ucm board go bad on me yet but could this be? I can jumper the orange to a ground and contactor pulls in and all is well till it's suppose to satisfy lol. Is there a way to test the ucm board?Name:  ImageUploadedByTapatalk1355257057.549033.jpg
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