11-27-2013, 10:45 AM
Need a little help troubleshooting my shop heater. It is a mr. Heater brand 175k btu forced air heater. I have kerosene in it. It is the contractor series. I can start from cold and it runs fine for about 10 minutes. Then it starts putting out smoke and quits. Diagnostic light on the side indicates no flame detected. Cannot start it again until it has cooled down. Any ideas?
11-27-2013, 10:46 AM
Replace the flame sensor.
11-27-2013, 10:56 AM
Is it an optical or electrical flame sensor?
Optical flame sensors (the typical sensor in a salamander) can get dirty. They can also be fooled by too "clean" burning a flame. If the flame is too lean, that could be a problem. Do you know how to adjust the flame in one of these?
Is it spark or hot surface ignition?
Spark ignition works off an ignition coil that is in many ways similar to an engine's spark plug coil. The coil may stop working when it gets hot.
11-27-2013, 11:06 AM
Try replacing the nozzle first. Should be able to get one for about $5 at any hvac supply house. Pull the old one out and they should be able to match it up for you. Also inspect the inner parts of the burner. Usually when mine starts to smoke a little the nozzle is dirty.
The flame sensor is probably doing its job if the flame went unstable and started smoking. I wouldn't rule it out but I don't think its your culprit yet. I would be after why it starts smoking after 10 minutes first. If the flamse sensor quits the whole unit would shut off which doesn't explain the smoking.
The one I have isn't constant ignition. It fires the spark electrodes for 15 seconds until the flame gets going that it cuts out. If you had a pulse in fuel pressure such that the flame snuffed out it would cause this. Also check the in tank filter.
11-29-2013, 10:29 PM
I cleaned the flame sensor. Cad cell type. It ran for 18 minutes this time before doing the same thing. Checked air and fuel filters, both good to go. I will check the nozzle when I get home.
12-28-2013, 01:41 AM
Hey, I've got the exact same kerosene heater as the OP (Mr Heater 175K) and am getting the "no flame detected" message after about 15 seconds of the fan blowing but no ignition. Ends up with raw fuel running out the front.
I'm just running #2 diesel in it (is that a problem?).
My manual has nothing about repairing or doing maintenance on this. Are there any directions for changing filters, sensors etc?
12-31-2013, 10:01 AM
This may or may not apply to your situation, but whenever I've had problems with my Dyna-Glo Pro torpedo from Home Depot, it has always been hose problems.
I recommend burning only number one Kerosene. Burns very clean, can barley smell it, and no burning eyes, etc. And your lungs will thank you.
The first time I had an issue, the stock fuel and air hoses had literally disintegrated after only 2-3 years of use. I replaced them with automotive grade fuel line and away it went.
A couple months later it started running dirty (odor and smokey). Checked the hoses, sure enough the fuel line had partially slipped off the barbs at the manifold end. Put a hose clamp on all ends. tried to start it and it would only cough and fart then stop entirely with a big puff of smoke.
Checked the hoses again and one end of the fuel line, at the manifold was wet. Apparently a slice in the hose. Replaced the fuel line with a better grade of automotive fuel line, and away it went, burning nice and clean again.