Monitor 422 Fan

[dtjacob]

Heater was running fine this afternoon, then it shut down & the burner light was blinking. Re-started, burner came on, but the circulator fan never came on, & then the burner shut down. Reset the board (unplugged power for a few minutes), re-started, & the same thing happened. I know that there are a couple of fuses on the board, does either one of them control the blower???? If not, where should I start looking???? Just trying to get some info. before I get into this......... Thanks.

[hawkins111]

M422 trouble

Have you looked at the fuel level, filter on tank, vent on tank? When was the last time the unit was serviced? The fuses do not control the fans. You would get an awful lot out of reading every post on this site that has anything to do with a Monitor 422. You need to understand the cycle the stove goes through in order to run correctly. There is a post on here that will get you a manual. There is info in the manual that will get you much more informed about the heater. Read everything you can and get back to us. Tom

[dtjacob]

M422 Fan

Hi: Having trouble writing a message, which is why my previous post was kind of sketchy........I seem to be unable to start a new line or paragraph, can't move the cursor with the enter key or the mouse. Doesn't really make sense to run everything all together. Can anyone help, maybe I have a wrong option selected??????? Anyway, here's what's going on: burner starts normally, flame looks fine. Burner runs for 2-3 min., hear the "clicking" as things warm up. Circulator fan never turns on, I'm assuming the overheat sensor trips at this point. I have the service manual, looks to me like hopefully the fan switch is not turning on or a wire is unplugged. Totally rebuilt the burn chamber last fall with all new parts, worked fine all winter. Using the internal fuel tank, that is full. If the filter was plugged, I wouldn't think the burner would ever come on????? The heater was working fine, when I went to check on it, it was shut down. Will do some troubleshooting later today.

[hawkins111]

M422 trouble

If you can see a flame in the pot and it is strong when the status lights come on you have something going on with the flame sensor. There is nothing wrong with the sensor, it’s just telling you it did not recognize the flame. Carbon on sensor, sensor touching the pot or ring, burner mat lifted or eroded, burner ring warped. If the flame goes low in the pot and then the status lights come on you have a fuel problem, i.e. low fuel, dirty filter, blocked nozzle. If you hear a thumping noise around the pump area you have a fuel problem. Tom

[dtjacob]

M422 Fan

Hi Tom: Got into the heater this AM. The flame was real strong when the heater shut down yesterday, also ALOT of heat coming out around the circulator fan on the back, which made me think maybe the fan switch was the problem. As I said earlier, I rebuilt the chamber last fall with all new parts. First thing I did was pull all the connectors off the board & checked all the resistances listed in the service manual, all were within 5%. Then I checked the overheat sensors, which showed continuity cold.....not listed in the manual, but I think that is correct. Next, checked the fan switch, which was open when cold......again, not listed, but I think that is correct. Checked the flame sensor, which was not grounded. Sprayed all the connectors with contact cleaner before I re-installed them on the board. Started up the heater & it has run fine for the past 3 hours. I think that the problem was either a piece of carbon shorting the flame sensor (fell off when it cooled) or a bad connection on the board or both. Will post an update if the problem returns. Don.