New here, perplexing GF200 issue

[JBrock]

I have a Monitor GF200 (propane) that keeps shutting down after the heating cycle finishes.

Here's what I know:

Intake, Exhaust, all other airways are clear and free flowing. The heater comes on as it should, cycles up, ignites, runs beautifully as it should until it reaches temp. When temp is reached, instead of cycling back down, it shuts down and leaves you with the flashing burner status/readout display. The fan continues running for several minutes afterwards.

I'm handy and knowledgeable and learn by doing, but I know very little about the inner workings of Monitor heaters. On an unrelated issue as back story to this heater, about once a year the local dealer has to come service it and replace the igniters because it starts doing this hissing/popping thing. Other than that I've had no issues with it except the above paragraph. I'm guessing this new issue is unrelated because otherwise it would never cycle up and heat the room in the first place?

Any help would be appreciated.

[FordMan59]

I don't know anything about the Monitor gas units and how they are set up, but my 422 kerosene unit started doing the same thing a couple years ago. In my case as the burn chamber heated up and parts started expanding it was causing the old warped flame ring to short out against the flame detective rod and causing the heater to shut down as a safety precaution. I cleaned out the burn pot, replaced the burn ring/burn mat and the problem was solved. Will be 3 years in Feb. since I worked on it and it done fine ever since.

Edit: I may have misunderstood your post. Is the heater bringing the room up to temperature then shutting down or is it shutting down prior to reaching the set temperature? Mine was shutting down shortly after the flame started and parts started expanding. If yours in doing this after the room reaches the set temperature and time for the heater to shut down I'd suspect something electrical, time temperature controller, main circuit board, etc.

[HayZee518]

I would check out the flame ring as fordman suggested. the on cycle is the same as the kero unit, purge, flame, heat, then shutdown. the combustion blower should still be running and the circulator runs until the plenum temperature drops. the combustion blower is the first to come on and the last to shut down.

[JBrock]

Thank you guys, for giving me a place to start. I'll spend today looking into the flame ring.

Fordman: it is bringing the room to temp completely, then shutting down.

[hawkins111]

Is the circulating fan and cover spotlessly clean? Do not open your burner until you have a supply of gaskets or material to make gaskets. The gas units do not have a burner ring. They have a burner port, which is the thing with all the holes in it. If you are having a spitting and popping issue, you have moisture in your unit, (condensation, raw water in the gas). When you get your gaskets check the flame sensor. Tom

[JBrock]

hawkins111, I'm religious about keeping the monitor clean of dust and build up. Thanks for the heads up on the gaskets, I was about to start tearing things apart and I don't have any material for that.

You've got me curious about condensation because sometimes when I turn off my gas stove, the burner "pops". I have a large 120 gallon tank on the side of my house that is filled/maintenance by a local gas company. I was told by a friend that the popping issue on my stove could be due to a faulty regulator on the tank. I'm curious as to how condensation is getting into the lines or does that just naturally occur sometimes?

[hawkins111]

Moisture in propane can be a problem. It can come from your supplier or someone they get fuel from. I would think that if it was a water problem your regulator would give you trouble every winter when it gets cold. If all your propane units have issues I would look at the regulator. Tom

[dd20399]

Moisture in propane can be a problem. It can come from your supplier or someone they get fuel from. I would think that if it was a water problem your regulator would give you trouble every winter when it gets cold. If all your propane units have issues I would look at the regulator. Tom

gf 500 I know is some different but a full service manual is still online from bing search engine..put in gf 500 service manual and it will come up to download.. hope that helps you