Coleman Evcon DGAT075BDD blinking 5 times

[bsteiny]

This has been going on for almost 2 years now. I know that the code is "gas valve energized with no call for heat". I'm tired of the fan coming on and blowing cool air when the temp is above what the thermostat is set at. So every time this happens (which is a lot) I go to the furnace and turn the power switch off until the temp gets down to where the furnace will kick on. Then the furnace will work fine for sometimes a few days with no problems.The board has been replaced 3 times and the last time was about a year ago. Should I try to change the gas valve? If you could let me know the part number that I need it would be appreciated. Thanks.

[gordo48111]

The gas valve is not the problem. It is energized by 24V across its terminals which would normally come from the thermostat. If it is energized with no call for heat from the thermostat (this is what the error code means), the valve is being powered from somewhere other than the thermostat - most likely from the board itself. I have read several posts on this site about people having to replace boards every year or two. In my 25+ years in the HVAC/R field, this is not the norm. Voltage spikes can contribute to premature failure of a board and I recommend the control circuit be fused, if it is not already.

[Robert]

Test the gas valve for 24vac.
IF you have it, test board across W and C for 24vac.


Then trace wires from GV to board, unplug the connector and test across board corresponding holes/pins for 24vac that connect to GV wires.



Thanks,
Robert