Gatage Heater Issues

[mtb02]

I have a Modine HD45AH0134 garage heater that was in the garage when we bought the house, that was one of the best parts for me!
Any ways the heater has worked great up until this year.
At first it would light then go out right away but after cleaning the flame sensor this is what it does now:

- The exhaust fan comes on
- The igniters heats up (glow red)
- The flame lights
- The blower fan comes on
- The heater runs for a minute or so
- The flame goes out (all fans still running)
- In about 30 seconds it re lights then does it all over again.
There is no error flashing on the light in the heater it is going bright dim which indicates normal, exhaust vent is clear and everything looks clean.

Does anyone have any other ideas I could try?
Thank you

 

[LS6 Tommy]

Fan/limit switch is going bad...

Tommy

 

[mtb02]

Thanks, I'll give that a try, I just ordered the parts, it doesn't look like anyone close by deals in these parts.

 

[DenisG]

http://www.qcsupply.com/commercial-...rage-shop-heaters/modine-hot-dawg-heater.html

The HD45 is in the "Hot Dawg" line of heaters. See the above link for the Wiring Diagram. You might want to verify that your thermostat is working properly by jumpering "R" and "C" on the terminal strip (see page 13 of the wiring diagram) and see if that solves your problem.

 

[frankush]

Make sure your vent is not obstructed also. I agree that it's probably shutting down due to high temp in the vent. I've seen snow covered vents create the same condition.

 

[RDesigns]

that happened a few weeks back at work. the exhaust was covered in snow due to it being on a wall above another roof the snow drifted over and covered it would blow back thru the burner tubes and shut off.

 

[Adk Mike]

Change the polarity on your wiring. Just switch them around . It may just do the trick.

 

[mtb02]

Well the limit switch didn't fix it, or a new flame sensor, The exhaust is clear up to the cap, but I have to check when its light out to see if there is anything stuck in it on the roof.

 

[sprntpshr]

Didn't see it but have you checked if the pressure sense line from the pwr venter to the pressure switch is clear? It may be partially blocked or the hose bib on the venter corroded.

 

[mtb02]

I jumped the thermostat tonight with no luck... Will work on it more tomorrow.

 

[DenisG]

The pressure switch is a simple switch to check for exhaust flow. You can also jumper that to see if that is the cause of the problem.