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Joe Chritz
02-23-2007, 3:12 AM
Modine Hot Dawg help.

My 45K Hot Dawg is no longer firing like it supposed to. It will start the fans and ignite the top burner for a few seconds then re-cycle and do it all over again.

Anyone seen this problem before? It only gets used overnight and on my working days since I installed the woodstove.

I did bypass the thermostat and it does the same thing.

Thanks in advance

Joe

Pat Zabinski
02-23-2007, 7:15 AM
I had a similar problem, and it turned out to be an internal thermocouple used to protect the unit from overheating. It's been long enough ago that I don't recall the details, but I was able to pick a replacement at a local heating supply store for about $15, replace it myself, and had it running in short order.

If the unit is in your shop, you might consider cleaning it inside/out to ensure dust is not slowing air flow, which can also cause over heating.

Al Willits
02-23-2007, 8:53 AM
Be unusual that a high limit would cycle in a few seconds, possible but unusual.
Not familiar with that heater, but does it have electronic ignition?
Seems they have a HSI ignition if I remember right, that is there's no pilot, but a glow coil ignitior comes on, heats up and then main burner gas comes on and the ignitor fires the gas.
I'm thinking there may be whats call a flame sensor in the circuit and if that gets dirty it will cause the short cycling you see.

Look for a thin rod that the main burner flame hits, probably be next to the glow coil and it probably will have a wire coming off the bottom of it going to a module or valve.

If so, shutting the unit off and carefully cleaning the sensor with a scotch brite pad may get you going again.
Stay away from the ignitor, they are fragile.

Throw in the required "I ain't responsible for what you do" stuff...:)

Al

David G Baker
02-23-2007, 9:11 AM
Modine Hot Dawg help.

My 45K Hot Dawg is no longer firing like it supposed to. It will start the fans and ignite the top burner for a few seconds then re-cycle and do it all over again.

Anyone seen this problem before? It only gets used overnight and on my working days since I installed the woodstove.

I did bypass the thermostat and it does the same thing.

Thanks in advance

Joe
Joe,
I have the Hot Dawg 75,000 BTU that is natural gas fired. I shut it down for the Summer and when I fire it up in the late Fall mine has similar symptoms. I have a pipe tee with a valve on it that is on the outside of my pole barn where the pipe enters the building that has nipple with a pipe cap on it. I shut the main valve off, remove the pipe cap, and bleed the line. For some reason what ever is in the gas line after sitting without use is not flammable. I have to do this every year or the burner will not ignite. You didn't say if your unit was propane or natural gas.
Because you have been using yours on occasion this is probably not your problem but it may be something to look at if the above suggestions do not pan out.
Another suggestion, if you do not have any luck, do a Google search for Hot Dawg problems.
Good luck
David B

Jim Becker
02-23-2007, 10:55 AM
'Had a similar problem with our gas furnace this week and it was a bad pressure switch. Be sure that there is nothing blocking your air intake, exhaust and any condenstate pathways, if any, in addition to the expert's advice...

Ben Grunow
02-23-2007, 9:50 PM
Hey Joe- check your gas tank! Mine (HD 45k) ate 100 lbs in less than 3 weeeks set low with good insulation and did what yours is doing (have a little propane odor as well?). Hope this is right as the fix is easy and only slightly embarassing DAMHIKT.

Ben

Joe Chritz
02-24-2007, 2:32 AM
Firstly - apologies to the mods for posting in the wrong area. I musta been having one of my ummm "moments". Those responsible have been sacked. (extra credit if anyone knows what movie that is from)

Secondly - Ben I did check that but it is good. I run off a 250 gallon tank so I don't have to fill all that often.

Thirdly - nothing seems to help so its time to call tech. The top section lights every time but the other two do not. I was able to get it working a few times (on its own) and when the other burners light it runs fine. The flame sensor is on the bottom burner.

I am leaning toward low pressure not allowing the flame to "migrate" so to speak.

Thanks to the help

Joe

Al Willits
02-24-2007, 10:11 AM
Missed the only partial burners igniting, if you have only one of ? burners lighting, I'd get someone out to look, that could get dangerous.
Please be careful, you can get some pretty impressive explosions from delayed ignition.

If your not familiar enough with the unit to do a pressure test on the burner pressure (prob about 11" wc for most propane units) or remove burners/orifices to check for obstructions, I'd stay away from playing with it.

Good luck and let us know what happens.
Al