Monitor 22 - No fuel, lockout

[jefftrent]

Hi. New to this forum -- great forum, BTW. I've been through dozens of threads and still cannot get to the bottom of my problem. I get through the initial purge, my igniter fires up, but I'm getting no fuel to the pot. I've cleaned the sump, cleaned the screen, cleaned the solenoid pump and screen, checked the float level (twice), but the solenoid pump will not operate. I get a lockout condition with flashing red lights.

I have a unit that uses the drop in fuel capsules.

Here's what I've done:
Combustion chamber rebuild: new pot, ring, burn mat, flame rod, gaskets
Cleaned the fuel feed line from the solenoid to the C-chamber with carb cleaner - flows fine
Confirmed positive pressure to the air pressure switch, and that it clicks when the unit is on
I jumpered out the APS with no results
I jumpered out the two thermo resistors at the top of the front panel with no results
Verified operation of the combustion blower motor and positive connection to the bottom of the pot
No obstructions on the intake or exhaust
Verified resistance of the solenoid pump across the terminals at 660 ohms

What's left? I think the only thing I could be looking at is a bad pump. Any help is appreciated. It's getting cold, and electric heat is expensive! Thanks!

[hawkins111]

M22 not starting

Jeff,

When you try to start up and the status lights come on do you hear a thumping noise? If so the pump is either not getting fuel or is worn out and not pumping fuel. If you don’t hear a thumping, jump the wires on the air safety switch. When they are jumped and the status lights are steady you should have 105 volts DC at the orange and black wires of connector K. If you have 105 volts DC you have a pump controller problem. If you don’t have 105 volts DC you have a bad circuit board. A bad board can be fixed by Mathis Electronics. At this time Mathis does not fix the controller board.

Tom

[jefftrent]

Thanks for the help. My connector has 3 wires: yellow, brown and blue. When I connect the multimeter from all three to ground, I get about 55 volts. Am I missing something?

[hawkins111]

Connector K

Jeff,

Remove the connector from the fuel pump controller. You should be able to get the 105 volts DC from the Yellow and Brown wires. It's been a long time since I have seen a M22. You will only get the voltage when the status lights are on and steady.

Tom

[toomedic]

Just to confirm, did you clean the little tiny filter accessable on the side of the sump? No need to remove the sump, just a little tiny access point on the right-lower side of your heater two phillips the metal plate comes off, then you have a spring attached to a cylindrical filter. Just checking...

[HayZee518]

other readers suggest to remove carefully the capillary connection on the pot and stick it into a small jar and start the heater. if the pump is working you should see pulsations of fuel entering the jar. then if not either the controller [TAISAN] or the pump itself is shot.

[jefftrent]

Results:
Yellow & Brown = 0 V
Yellow & Blue = 109 V
Brown & Blue = 109 V

[jefftrent]

Since no voltage on yellow and brown, I need a new or repaired board.

Any chance I got the brass donuts inside the pump solenoid installed wrong when I cleaned it? The two brass donuts go on top of the nickel/steel one, right?

[hawkins111]

M22 fuel pump

Jeff,

If you took the pump apart all bets are off. The only breakdown picture of a pump that is anything like yours I have seen was for a Toyo boat heater. I would not trust it being correct for yours. Since you have the correct voltage on any of the wires I think your main board is OK. I also think the controller is OK as well. I can not help you with the pump as I would not take one apart due to the liability. You will have to search all the dealers around you to see if you can find a pump.

Good luck,

Tom

[jefftrent]

I don't think I actually took the pump apart. I removed the 4 mounting screws on the solenoid housing so that I could remove the plastic nozzle to give it a proper cleaning. Up inside the hollowed out portion of the top half, there are 3 donuts. 2 are brass, one is nickel/steel. It seemed like the correct orientation would be two brass donuts on top, they are larger. The other one on bottom. Is this correct?

[hawkins111]

pump break down

Jeff,

This picture is a Toyostove solenoid pump. I hope it is similar, it's the only one I have.

Tom

[HayZee518]

I hafta back up Hawkins. I took apart a taisan pump for a M41 back aways and wasn't able to get it back together also. That and the level screw in CLV I don't mess with!
anyway maybe helpful, because the pump pulsates in operation, the nickel steel sleeve might be the pumping body on the spool. fuel is drawn up into the spool and out the capillary. there must be a steel check valve ball somewhere in it to prevent a backflow during off times.

[jefftrent]

Sort of fixed!

I took the pump back apart. There is actually one nickel/steel donut that's fixed at the top, a small brass one in the center, and a large nickel/steel one on bottom. I had the two bottom two reversed. As soon as I hooked it back up and heard the "thump, thump, thump, I was in good shape. Nice blue flame.

Now another problem, after about 3-5 minutes of operation with circulation fan on, full flame and high heat, the unit shuts down. Seems to point to flame rod circuit failure (?), even though I just replaced it, and visually inspected it to see that it isn't grounding out against the combustion chamber. I guess I should probably make up a flame rod bypass circuit tester.

BTW, hawkins111 and HayZee518, you guys are great offering help on this forum -- much appreciated!

[jefftrent]

Pulled the flame rod. It looked fine. But the flame rod back in place. Plugged the unit back in and started it up. It's been cycling fine for hours now! I wonder if the initial burn off of glue and gasket material caused the air in the combustion chamber not to ionize properly causing the flame rod to knock out the fuel pump. Anyway, it's throwing nice heat now with an even blue flame!

I had never torn into one of these before this other than a general cleaning of the fuel delivery system. It just goes to show that with a little patience and direction, these aren't so tough to work on. Besides, I've learned a ton about this unit and feel like I have the knowledge to maintain it for years to come.

Thanks to everyone for all your help!