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We have a Coleman Evcon model# DGAT070BDD. Last night we turned on our heater in anticipation of some cold temps. It worked fine and heat came out. Then this morning when we turned up the thermostat and nothing happens. You can hear the thermostat click but nothing happens with the heater. There are no codes flashing. The green light is steady. When we flip the heat from auto to on the motor turns and blows cold air. But it is acting as if the thermostate isnt telling the heater to turn on? Would anyone have any ideas where to start to figure out what is wrong?

Thanks for your help

Hi,

See if you have 24vac across W and C on control board.


Thanks,
Robert

We have 24 at W but 0 at C. We Have also put in a brand new transformer and still having the same issue

hi, there

u say u have 24v at W board terminal, but zero at C. i believe Robert wants u to place 1 meter probe on the W terminal on the board and the other meter probe on the C board terminal and ck for 24v. i am curious as to where u put meter probes an got 24v at w terminal and 0 at C terminal.
make sure meter is set for ac voltage.

Yep, one meter lead on W and other on C for 24vac.

Do same on board at 24V and COM on board.



Thanks,
Robert

ok we have 24 thats not the problem, I think we are having issues with the booster motor I took it off and spun it by hand and then turned power on to it and it kicked on and ran for couple of seconds then kicked off so either the booster motor is no good or something esle is going on?
There is black wires going to booster motor and blue wires going to the centrifugal switch, one of the blues is showing 24 the other 0 until you open switch by hand then it shows 24, but the black wires show 0 on both, does the black wires need to have current running thru them?

You have 24vac to the board, but no voltage to the motor. The board will send power to the motor.

Could be a bad board, motor or a loose wire.


Trace black wires back to board and see if 120vac is being applied across them at same time you have 24vac across W and C.



Thanks,
Robert

okay this is what we have so far, I did some more tests tonight after work. Turning everything on thermostat up and green light is steady on no flashing but nothing happens, so did what you said put probes to w and c and have 25vac at those then put probes to the black wires going to booster motor and got 0 and when I turn the power switch on and off I will get some current thru black wires it jumps like 5 to 25 or even up to 120 but then goes right back to 0 so do you think it is bad board or something else? now I know that the booster only powers on at initial start up so is there something else i can test or is it all right out of the board? I also checked to see if it was just a loose wire but even unplugging the harness where the black wires go into and test it right off the board and get same results. Sorry to ask so much and be a pain I just want to make sure before spending 150 dollars on a board. I appreciate any help or insight you may have. I do plan on buying a new board by the end of the week cause at this point I just dont know what else to check. thanks again

Hi,

Integrated Control Board # 7990 - 319P can be seen and ordered from here by paging down:

http://www.aberdeenhomerepair.com/store ... rd-L38-814


Also have link there for possibly being able to repair your board.

When the t-stat calls, it sends 24vac to W on the board. At that time, the board sends 120vac to the booster motor.

With that not happening and also the diagnostic bulb not flashing, I would suspect the board as being at fault with info I have not being there in person.



Thanks,
Robert

Hi,

Thank you for the info and the help Im sure it is hard to diagnose a problem over the internet
I will probably try sending the board in to see if it can be repaired first.

Again thanks for your help,
TJ

Hi,

You're very welcome, happy to help.



Thanks,
Robert