Monitor 441 keeps shutting down

[JS57]

I own a monitor 441 which has developed a problem. I live in a remote Alaskan village which has no dealer and is accessible only by air so my resources here are limited

I have had the unit 5 years, I do not know how long the person had it before me.

The problem is as follows. The unit ignites (combustion chamber and heat exchanger get hot; flame appears to be yellow) however in about a minute the controls shut it down. The sequence is, blower on for about 3 minutes and 20 seconds, then ignition, then about 1 minute after that the flame indicator shuts off on the panel followed by complete shutdown another minute or so. Then the flame indicator on the panel flashes on and off. No codes are present.

I have verified fuel is present and flowing, ceramic igniter is working and cleaned the tip of the flame detector so it is carbon free (was not much build up was there).

If anyone has a best guess on what the problem is and what might fix it any help would be appreciated. I have the owners manual which is virtually useless to work on the unit with so if there is a technical manual or bulletins I would be interested in purchasing those also

[adnadeau]

Sounds like your flame detector is not working. The whole detector rod should be clean--not just the tip--and should be centered between the combustion ring edge and the chamber wall. If you have a voltmeter, connect it between TP6 and EP on the printed wiring board. On combustion startup, it should read 0VDC and gradually rise to 1.2VDC minimum as the flame builds. There has been a service manual available on-line occasionally, but it seems to have disappeared for the moment. Also, make sure the fuel is getting to the burn chamber continuously. If you hear a difference in the pulse sound coming from the fuel pump, it means it's sucking air. This might happen if fuel is flowing into the float bowl too slowly from your tank. If that happens, push the Fuel Set Lever on the side and see if the flame picks up again.

[HayZee518]

to verify if the flame detector is working, make a test jumper. get a diode and a 100K resistor - connect the resistor in series with the diode. when the heater starts and is done with the purge, put the jumper in place of the flame detector leads. polarity does make a difference so if it don't work first thing reverse it. if the heater starts and fires up and stays lit then the flame rod is shot if it still doesn't stay lit then the flamerod electronics on the main board is shot. orange tipped flame means not enough of air to the combustion chamber. or the damper is not opening.