arne97

Have a Monitor 441, about 10+ years old. It came with the house . This is a kerosene vented heater.

Last night the outside temp was about 8F and the unit stopped working.

The fire ring will burn but shortly after the heat exchanger fan goes on, the fire goes out and the unit shuts down. The flame is a nice steady blue.

Referring to manual , I cleaned internal fuel filter. Checked level of fuel in tank.

Removed external fuel filter and cleaned filter insert. Fuel appeared to be running fine from tank to filter.

It is VERY difficult to get info on this heater, such as repair manual.

I don't have the cash to replace the unit before Spring.

What can I do to diagnose and fix??????????
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glennjanie

Welcome Arne:
I hope you don't have to go through another cold night.
Check for a High limit switch, the unit may be getting too hot for the worn out switch. It will look like a big, big watch battery with a little frame around it with 2 screws to hold it on.
If you have a multitester you could fire the furnace up, check for voltage across the switch; it should be a 'normally closed' switch. Keep the tester on the switch and just before the unit kicks off the switch will open, That's what kills the fuel supply.
Another thing about kerosene heaters is a photo-cell that checks for a flame and, if it doesn't detect the flame after 90 seconds it shuts off the fuel. Take the photo-cell out and clean the surface of it; it may be carbon coated to the point it can't see the flame.
Glenn