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Author Topic: Control board blower for HVAC  (Read 762 times)

Offline dagoose

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  • Member Since: Jul 2016
  • Posts: 2
Control board blower for HVAC
« on: July 11, 2016, 10:44:25 AM »

Well I am new to HVAC units but have a good knowledge of electrical components. My question is that I am suspecting that my replay on control board might be fault. I have power to the blower and it is attempting to start up and this is a new unit with a new capacitor but the voltage I am obtaining is not 120 but 110 volts AC . is this two low to start the motor? also I am getting voltage on cool terminal and voltage on heat terminal and when I took out control board I notice that the relay that is on the cool and heat terminal is on different sides. the heat is on NO relay terminal and the cool is on the NC terminal and if my assumption is write about relays then only one terminal should have voltage at any given time correct?

I don't want to make this super long and any help iwould greatly appreciate it. I fix tvs and this seems easy enough to fix but have no knowledge about hvac but I followed the schematics . doing this for an aunt and she has no money to pay for tech so giving it a shot . the original tech said it was the motor so we boutght a new one and returned it because same issue so got the second new one which they tested out on site and it works but got home and same issue and also both times had new capacitor.

Another thing to note is that it would point to a capictor problem but it is not and this I bring up because when I turn the blower by hand it starts up with no problem. I have 124 volts coming in at the safety switch in the furnace upstairs and therefore my concerne is why there is only 109-110 volts from the cool terminal to the neutral terminal . is it normal for the control board to consume about 14 volts which would be needed to turn the motor on? and would it be losing power beucase both the cool and heat termnials have 110 volts threw them at once? thanks so much if any picutres or any information is needed please let me know.