Hot Dawg 45HD heater

[Skipper_52]

I bought this unit new in about 2004 and had (2) issues over time. The igniter element gone bad and had to replace the board. The board is an older type without led lights for error codes. I just replaced both of them again but can't get the flue fan to turn on.

Flue fan operates when jumped.
Gas valve has solid green.
Vacuum switch tested good.
Thermostat operates fine.
Main blower fan turns on without gas igniting and will run for about 10 minutes or so with no heat.

When operating correctly the following should happen.
1. Flue fan turns on.
2. Igniter gets red.
3. Gas valve opens and ignites gas.
4. Main blower fan turns on until temperature reached.

My gut feeling is it's the gas valve although it shows solid green. Can anyone help?

 

[gmcgeo]

Whats the error codes, sounds like a board issue. Gas valve would not command the blower fan to come on if not working.

Sounds electrical

to be sure, test gas pressure at manifold, then at incoming on valve

 

[Skipper_52]

It's the gas valve. I've got power to the valve on the exhaust fan side and no power coming out to the fan. GD valve is $400. Time for a new heater.