Monitor 441 Heater

[adnadeau]

Flame detector test

There's a sidebar in the troubleshooting section of the service manual showing how to make a flame rod bypass circuit for testing purposes. It's a 1N4004 diode and a 100K resistor in series which you connect between ground and the "O" pin on the PWB at the correct time as explained in the sidebar. This allows you to tell if the problem is the flame rod or on the PWB.

[HayZee518]

the way it was explained to me is that when the rod is cold there is an ac voltage on it. when there is a flame its characteristics change so that there is a dc voltage on it now. as long as there is a flame on it, its output is dc. the paper suggests using a 100 ohm resistor in series with a diode using alligator clips. the resistor is a current limiting device and the diode changes the ac to dc. when you are in that part of the cycle after purge into prime and ignition, put the diode into the circuit and see what happens. if your polarity isn't correct, the unit will go into lockout and you'll need to reverse this polarity by switching around the leads. go through the whole purge, prime, ignition cycle and re-connect the diode device. if the unit stays lit then you found a faulty flamerod. if it kicks out then your control board is shot.

[dick_fischbeck@yahoo.com]

What if I remove the flamerod, close the opening with tape and apply a propane flame to the rod when the burner lights? If the unit then shuts down, it's probably not the flamerod malfunctioning. I guess I'll try that. I don't have the suggested test circuit.

[HayZee518]

make one! go to rad shack and get a diode and a 100k resistor. solder the diode to gether and a couple of alligator clips. merely heating the flamerod outside the heater won't work because there is no ground reference. read the sidebar description.

[Decos]

Monitor 41

Hi All, I hope you don't mind if i invade your thread. I also have some questions about 'the heater'. (i'm also glad to hear the same feedback about Al. i thought i was just being incompetent on his site) I cannot seem to find parts for this unit. I'm looking to find a replacement for a warped burner pot (i think this is the correct name) My husband can do repairs if i can research and find parts and directions. I do have an owners manual which i am happy to scan and forward to anyone through email. It does have a maintenence section, (small), but i have no repair manual, which i am looking for. If anyone can help me out with parts, i would be indebted. Except for maintenence, I have had good luck with this unit, and am happy with the performance. It heats our whole house quite efficiently. I also have a Monitor KWH24 water heater, which i'm sure by this point could use some maintence. Any resources out there for this?
Thanks in advance for any assistance. I'm just very frustrated trying to find parts.
Dee Costigan

[HayZee518]

a company nelson & small in maine has replacement parts. mind you the replacement parts are not cheap! my monitor [M41] finally gave out. I got a new m2400 to replace my "out to lunch" unit but will stay on it [repairing] the heaters. so if you have any questions I'd be glad to entertain any request. I have a pdf file of the service manual. this manual covers the M441, 422, 21, and 41 heaters. the large can in the unit is the "combustion pot." on the side of it is the "view port" inside of it is the combustion ring. in the side of the pot is the igniter and the flame rod. way inside on the bottom is the burner mat. other parts, the dealer called the fuel sump a carberator but it really isn't a carberator. there is a tubular screen that gets clogged with junk. there's two screws and a gasket that comes out and the filter is inside. the large screw bleeds out the fuel in the sump. there's a lever that resets the fuel sump lockout. give me an email address and I'll send you the service manual.

[Decos]

Dear HayZee518

Thanks for your quick and very informative response. Much appreciated. I actually do have the very same manual that you referred to in your pdf file. I also found a website that has a comprehensive picture layout of all the parts along with a listing of their names. Unfortunately, part of the page is cut off, identifying the very parts you so kindly listed for me. I think what i need is the combustion ring as it is fairly warped. Do you have any contact info for Nelson and Small in Maine, or a city....? I would be happy to contact them for parts.

Here is my address Jeff_and_Dee@comcast.net

I want you to know how much i appreciate your help. Thanks!

[HayZee518]

the url is: www dot nelsonsmall dot com.

[sidol]

Good Evening

a company nelson & small in maine has replacement parts. mind you the replacement parts are not cheap! my monitor [M41] finally gave out. I got a new m2400 to replace my "out to lunch" unit but will stay on it [repairing] the heaters. so if you have any questions I'd be glad to entertain any request. I have a pdf file of the service manual. this manual covers the M441, 422, 21, and 41 heaters. the large can in the unit is the "combustion pot." on the side of it is the "view port" inside of it is the combustion ring. in the side of the pot is the igniter and the flame rod. way inside on the bottom is the burner mat. other parts, the dealer called the fuel sump a carberator but it really isn't a carberator. there is a tubular screen that gets clogged with junk. there's two screws and a gasket that comes out and the filter is inside. the large screw bleeds out the fuel in the sump. there's a lever that resets the fuel sump lockout. give me an email address and I'll send you the service manual.

This is such a great forum...my husband is wondering if we could get the service manual to the M41. He has checked the pump (getting fuel) and had the chamber top off and cleaned soot off the top, none on inside that I could see near the bottom. The heater keeps cutting off after a few minutes of trying to run. Had it running this summer to make sure it'd work, but now won't stay on.
It's 29 here in Boone, NC windy and cold, so I'd like to get the thing running if possible.
idoltire@hotmail.com

[mike45]

My MPI 441 isnt workin and its cold outside.

My 441 was working fine last night. I woke up this morning and turned it on. It did its normal thing pumping the kerosene for three minutes and what ever else it does in those three minutes. Then it flamed up for a little bit, a bluish flame. It burned for a few minutes then went out. Now the burner status light is blinking with all bars lit up. Im sure if I had an owners manual or something I could figure it out. Maybe someone could help. My wife would appreciate it very much. If you have any suggestions or pdf manual of some sort you could email it to me at mikeer123@yahoo.com
Thank you.

[mike45]

it works now yyyaaaaa !!!!

It looks like all it needed was a good cleaning. I vacumed out the heat chamber or whatever you want to call it. I took out the heater on the bottom of the chamber and vacumed every thing out. There wasnt a whole lot of loose stuff in there. Maybe I just got lucky. I love it when that happens. Now my wife thinks Im the best, plus i saved some money. HEH, HEH.

[veggigolf]

Hi, sorry to continue this thread but it seems this is the place for Monitor heater problems. I read in part of this thread that if the float is down, to adjust something in the left rear of the float chamber. What's going on with mine is when the chamber fills up with kero, the float magnetizes to something and stays up there. Then the pump drains the chamber and the float stays there. I can push the red button and get it to go down, but then when it comes back up it sticks every time. Anyone have a suggestion?

Thanks!

[veggigolf]

After looking at the manual download (see "The DEFINATIVE Montior thread")
I did not see anything about servicing the "constant level valve". It appears that the magnet is some sort of safety shut-off. Am I right in assuming the float should not be engaging the magnet every time it fills up?

I removed the magnet from the plastic case and the heater seems to be running fine, no overflow, plenty of fuel to the pot. But I'm scared that if something blocks the needle valve I may return home from work to a house full of kerosene!

Any advice is appreciated. I actually have a 422 but it is very similar to the 441. I did run this heater 2 years ago on 20% biodiesel and did end up with problems. Nothing like the major funkness problems others have reported after using 100% bio, I've just cleaned the fuel components occasionally and changed the filter.

[HayZee518]

the constant fuel level float is basically a float within a chamber like an old car carberator. the float pivots on a wire rod and on its extreme end is a springy like tang that contacts the needle valve. there is a extremely fine grub screw with a slot in it that you vary in or out to adjust the level of the float. too far in won't give you enough of fuel, too far out will overflow the chamber and lock out the system. if there is a surge in the chamber the float goes up and contacts the magnet which holds the valve closed against its seat. the old m41 heater used a mechanical toggle-over center lockout with a spring. USE ONLY K-1 OR DYED KERO - DO NOT USE BIODEISEL! Yeah its cheaper and easy to produce, but creates a lot of problems with monitors. I heard that bio is slower than mollasses when its flowing IF its not heated. It also gums up the solenoid pump and at $146 a whack I'll use kero Thank You. I can help you with most problems for an M41 or a 441 heater other than the computer board which I have no references to rebuilding. I have a pdf file service manual for the 41, 21, 441 and 422 heaters. I'm still looking for a manual for the 2200 and 2400. My supplier said he'd get me a service manual for the 2400. I'm still waiting!

[veggigolf]

Thanks Hayzee. Yeah, I found out about B20 kerosene (80% kerosene, 20% biodiesel) the hard way. Hopefully by now (2 years later) I'm at the end of those problems! Even at 20%, biodiesel seems to break down kerosene, making it cloud up, clog filters, gum up solenoid pumps, etc. There should probably be a sticky thread warning people not to use biodiesel with monitor heaters.

The heater ran just fine last night without the magnet, but when I get a chance to get dirty again, I'll put the magnet back in, adjust the needle valve in and see if it trips the magnet. I'd much rather have that peace of mind that it would shut down the system if need be!

One more question: the adjustment screw you are talking about, is that the needle valve itself? I can adjust the needle valve, but I haven't located any other adjustment screws.