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R.G., HVAC Technician
Category: HVAC
Satisfied Customers: 319
Experience:  20 yrs. experience as HVAC technician, state certified contractor.
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Hello I just installed a control board part number 325878-51,

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Hello I just installed a control board part number 325878-51, perform system check out step 1. I had success then tried to perform step 2. connecting thermostat wires, install doors, turn power back on, turn on gas. I got nothing. can you help me.

R.G. : Hi, I'm R.G., sorry you're having trouble today. I will do my best to assist you in resolving your issue.
R.G. : Was same problem reason for board replacement?
R.G. : What color thermostat wire did you connect to what terminals?
R.G. : And do you have a volt meter to test with?

Hello R.G. I was told by a service rep that my old board needed to be replaced. So I purchase a new one and installed by following the directions. to answer your questions. Red wire to Red terminal, Yellow wire to yellow terminal, white wire to white terminal, 24v common to blue wire and green wire to green terminal. I have a volt meter

R.G. : Okay thanks. Was unit working before replacement of board?



It did start up on test though

R.G. : To test door switch will have to be engaged to energize unit, you can use a piece of tape to hold it down of needed

Correct I taped the switch flip on the power switch

R.G. : Then set meter to AC volts and check from 24v common terminal to R terminal on board and see if you get 24volts or higher. Thanks

ok will be back in three minutes

R.G. : Ok I will be here all night

27.5 volts

R.G. : Great now on thermostat turn fan switch to on position. Then test from 24v common on board to G terminal and see if we get voltage.



26.9 volts and the fan is running

R.G. : Okay thanks. Now at thermostat put fan back in auto position turn heat on and set temp above room temp to call for heat then check from 24v common to W terminal on board for voltage.

no reading from 24v to white but my burners are on and the blower is pumping out the heat.

R.G. : Ok it should have voltage back to W to start heat. Could you double check, make sure meter reads voltage from common to R then check common to C. Thanks not doubting you but meter could have locked up or not have gotten good connection
R.G. : I meant common to W not C
R.G. : Sorry for typo

I check from common to R and I had 25.9


common to white 25.6


i missed read last time my bad

R.G. : That's ok so far all checks out good. If want you can turn heat off, turn cool on and turn temp down below room temp to call for AC, then check from common to Y and common to G and let me know what you get and if AC and blower are running

I know I should check the AC but I'm confident that they are working. I have been cold for so long all I want is heat right now R.G. you are Ok in my book sir.


Ok I'll check out the AC give me a minute to warm up

R.G. : I understand. Just let me know if it gives you anymore trouble and we can troubleshoot further.



I'm good its after midnight I work on the AC tomorrow. Thank you R.G.

R.G. : Thanks for your patience and great troubleshooting.

You bet!

R.G. and other HVAC Specialists are ready to help you

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