The DEFINATIVE Monitor Thread

[HayZee518]

I had that yellow flame problem when I had a M41 heater. The burner head got real warped and upset the air fuel balance. I replaced the burner dome and the flames went down in size but were still there. the air flow wasn't there so I was gonna change the blower bearings but I gave up and called the department of social services. they had a plan that they'd replace the heater at no charge to me. I claim to be low income because of social security and the monitor was my only source of heat. two inspectors came out and looked at it and both decided the unit had to go. three days later I had a new heater delivered. with the new heater I have no problems with flame flare up, but the problem was from low air flow to the combustion pot.

[Keith]

Thanks to a 1-3/8" rubber drain plug with a slit cut in it I plugged the hole at the base of the blower shroud where the 4 wires go through. That helped. The low-med power flame has blue around the vent holes, but a tall yellow flame still reaches the top of the chamber. The hi power flame is blue around the vent holes with tiny white tips, and a bright yellow flame pops/flashes every few seconds in the center. NOW what?!

I also got a multimeter that tests volts, amps and ohms, but the instructions aren't that good. I'll take any help you can offer.

[Keith]

GREAT! THANKS! The ever-so-talked-about o-ring or seal where the damper wires go into the shroud DOESN'T EXIST on my heater... hmmm... Sounds like a possible source of my problem. I'll find some way to MAKE a cover for that hole with the wires passing through it and see if that makes a difference. Thanks again! I'll let you know how it works. I'll also get my M-441 photo album put together pretty soon.

[HayZee518]

the air proving switch measures the differential between the blower output and the air in the pot. when it is operating it closes a normally open mini microswitch mounted on the switch diaphragm. the two outer terminals, common and normally open. if this switch wasn't operating then you wouldn't get the fuel pump to operate at all. change the tubing next time you have the chance. because this switch is so critical try to avoid short pieces and no kinks in the tubing. the flame color(s) you described are typical. the sooting is from the lack of combustion air. the location of the solenoid damper is the lower left side inside the housing. all it is is a plastic flapper on a pivot that partially blocks or opens a passage in the shroud. the only o ring so many talk about is just a seal for the wires passing through the blower shroud. without this and silicone sealer air would leak out of the shroud. that air switch tubing leave it on the top hole, that's just an adjustment for the amount of air it takes to activate the diaphragm inside. don't ask me how it functions, it seems to go into the same area of the diaphragm unless there is another chamber inside.

[Keith]

So what does an air pressure switch do? The little black tubing on mine was cracked so I had to snip a little off the end and reattach it. It reaches now, but barely. I need to replace it. Would that affect my flame? Oh, and does the tube attach to the top or bottom hole? Mine's on the top hole. And my wires attach to the lower contact and the furthest one from that. There's one in the middle with nothing on it.

[Keith]

Yeah, HayZee, I replaced the mat with a nice one per your guidance from McM-C. While I had everything open I figured out that the fuel hits the mat, disperses itself through wicking action, begins to vaporize with the heat from the ignitor, finally ignites, then is pulled upward by the air current passing around and over the top of the burn pot overhead. It seems like a venturi thing or something. I never was good with carburetors.

[Keith]

OK... I've been paying a little closer attention than before and I hear what must be the solenoid damper. I also confirmed for myself that the combustion blower is single-speed and the room blower is two-speed. The fuel pump si also two-speed. When my heater turns on I hear a click and the combustion blower quietly begins the purge. After a few minutes I hear a thump (I assume this is the damper solenoid, either opening or closing, I don't know, and I don't know where it is) and the air speed in the chamber increases and I begin to see a glow in the bottom of the burn pot. This is when the fuel pump also starts, at its slower rate, and I have 4 of 8 "power lights" on. A minute or so later I see little blue flames creeping up into the vent holes at the top of the burn pot. Then I hear the thump (damper?) again and the air flow slows and the blue flame craps out and goes to a tall, mostly yellow flame with a little green flame around the vent holes. This is what soots up the window. It burns like this for several minutes until it reached the temp it wants, then drops to 2 of 8 power lights. Then a minutes ot 2 later, the lights go out, the fuel pump stops, the damper goes thump again, the air speed in the chamber kicks up, and the flame starts to go blue as it dies out. It purges for a few minutes, then shuts off. If I crank the thermostat up, forcing it to kick into high power, the change from med to high involves the damper thump, faster air through the chamber, the room fan kicks up, and the flame goes blue. After this, when it slows back down, I get the slower air, yellow flame, etc. It seems to me like the air speed in the chamber should stay high even at the low-med burn level. This would keep the flame blue. Any ideas?

[HayZee518]

the fuel is not mixed with air before it combusts. it is fed directly to the burner mat.

[adnadeau]

You haven't mentioned if you hear the solenoid damper operating. If you check the Normal Timing Chart in the service manual, you'll see it is on for pre-combustion and Low & Low-Med operation and off for Hi-Med and High. The combustion is shown as a two-speed unit which kicks up to High speed for the High heat setting. The schematic shows 110 VAC across the combustion blower for High and 88 VAC for low.

[Keith]

When it's on low/med power, it's getting way too much fuel for the amount of air flow. When it's on high power, the fuel and air flow are pretty well matched. Could I be getting to much fuel on low/med? Why's it running so rich on low/med?

[Keith]

I've seen the restriction rings where the inlet/exhaust meets the flex pipe and where the flex pipe enters the back of the combustion blower. I'll take those out. When it "shifts" from low/med to high, I can 1) feel the pulsing/clicking in the tiny fuel line between the pump and the chamber speed up and 2) hear one of the 2 fans speed up considerably. That's when the flame changes from a tall yellow-orange sooty flame and a non-glowing burn ring to a low blue flame in the vent holes around the edge of the pot and a red glowing burn ring. The 2 types of flames are very different, and appear to be the result of less/more fuel and low/hi blower speed. I know you've said that the blower is single speed, but SOMETHING is really winding up when it goes to high power and it sounds like a fan or blower. The air moving through the burn chamber appears to be moving MUCH faster. The tall orange (low/med power) flame just kinda dances around slowly; the short blue (high power) flame "flits" very quickly. It's like the difference between the starting and cutting flame on an acetylene cutting torch. If the blower isn't changing speeds, what accounts for the dramatic change in flame. I doesn't appear to be only fuel flow.

[HayZee518]

for electronic circuits a digital multimeter is always a must. but you'll be measuring voltages most of the time. the air blower fan is a two speed fan. the combustion blower is a single speed fan. what sounds like the speed picks up when the unit goes into high is the pulsations from the solenoid pump. a flame with yellow tips and much sooting is the combustion blower. with the unit off and unplugged, take off the flexible hose that goes between the combustion blower and the exhaust pipe. look into the blower for a restriction ring and also the exhaust tube OR the flex end that goes onto the exhaust tube. take out any restriction ring. this will increase the airflow to the combustion pot -as- you say it's spinning fast enough. the air holes in the combustion pot just below the combustion ring need to be cleaned.

[Keith]

I need advice. I have a Monitor 441 that came with the house in 2001. It's worked just fine (to the best of my knowledge) for 8 years. I refilled an empty tank in December then it did the typical burner fan > fuel pump > ignitor > flame failure > room fan > shut down > blinking display. Thanks to this website (in particular HayZee the Monitor Guru and McMaster-Carr), I now have a beautiful, custom burn mat, new gaskets, clean interior and so on. Now I have no more flame failure or blinking lights; but my flame is yellow-orange and soots up the window and burn chamber in less than a day. To be more specific, my half-power (4 light bars) and low-power (2 light bars) flame is yellow-orange and sooty and flares up inside the chamber. But my high-power (8 light bars) flame is blue with white tips around the perimeter of the burn pot with a slight yellow flame in the center over the glowing red burn ring. The burner fan sounds like it has one speed for low/med power, and speeds up quite a bit for high power. My intake/exhaust pipe is clear, as is the burner fan and the pipe into the bottom of the burn chamber and out through the radiator. I blew air from my shop vac into the burner fan inlet and it came out the radiator outlet in the same volume without any apparent hinderance. I suspect that there is some electronic part that controls the burner fan speed which is not working correctly. It could be that the burner fan just isn't running as fast as it should. The burner fan itself spins very quietly and easily, and takes several minutes to stop spinning after the heater has shut off. I think the bearing is fine. Here's my REAL problem. I do fine with mechanical things I can see like pots and mats and fuel and air flow, but I know nothing about electronics (since I can't see electrons). I need to know which meters I need to buy and how to use them and where to stick them and what they should read and how not to get electrocuted or short anything out or start a fire. Please enlighten me oh wise one(s)!

By the way, I've taken pictures of EVERYTHING I've done so far and will post them in the gallery as soon as I get my 441 dialed.

Thanks in advance!

[HayZee518]

the gasket insulation I've used is a ceramic fiber sheet stock - McMaster-Carr stock number 93235K11 - 24 inches X 6ft piece is $40.81

[HayZee518]

THANK YOU for the information. I'm sure we'll all benefit from this. Now let's just hope the cost is less than Monitor charges.