Monitor 21

[NEWHOPEFARMS]

restarting a monitor 21 today that looks new inside...using the internal tank...pot warmed up went to 4 bars..after a few mins went to 8 bars flashing...no thumping noise...removed capillary line it was clear..no fuel coming thru capillary linethough...any ideas here please?

[hawkins111]

M21 trouble

No thumping means no fuel pump. You could have a blocked exhaust or air pipe. We don’t know how long it been since that stove ran last so the combustion motor may not be turning or turning slow. If that’s the case the air safety switch won’t allow the fuel pump to come on.

Tom

[NEWHOPEFARMS]

M21

yes...I should have given more info...the heater was only used for 3 yrs and worked perfectly before it was put in storage.... it has not been turned on for 9 yrs probably...I looked in the plastic air pipe and there were numerous dirt dobber nest in there....lol...I do not hear any motor or fan come on during the cycle at all...my grandfather purchased and loved this heater before he passed away...I really want to get this heater going again....so thank you very much for any help you can give...

Jerry

[msearcher]

with the front grill off look behind the fuel pump and look for the combustion motor (with the plastic fan ). This should be spinning
if the combustion motor is working.

If its not spinning freely it may not be putting enought air into the combustion chamber.

[NEWHOPEFARMS]

m21

Tom...yes it will turn freely...but that fan never comes on during the cycle...

[HayZee518]

the minute you turn on the heater the combustion blower should run. its supposed to run all the time and shuts off when the set point is reached or when you manually turn the heater off after a short time delay. the fan runs at a constant velocity. its speed increases or decreases depending on the position of the damper solenoid flapper. check for power out at the combustion blower motor connection on the microprocessor. check the two fuses on the motherboard.

[hawkins111]

M21 blower motor

The combustion blower should come on right away. If it does not come on check the resistance on the black wires. Remove the wires from the main board and you should get 22 OHM’s. With the wires off, try to start the stove and check for voltage. You should see 92 volts AC to start with. If you have high or no resistance you need a new motor, no voltage you will need a new or serviced main circuit board.

Tom

[NEWHOPEFARMS]

m21

Thanks guys...will work on it 2nite and see what its doing....

[NEWHOPEFARMS]

m21

ok...checked..the ohms and amps...connection of the combustion fan to the motherboard was loose...cut the heater on...combustion fan started right up....pot heats up...fan is drawing air freely and exhaust air is good and warm and flowing good...goes to 8 bars and switches off..blower fan never comes on but the expansion chambers are hot....any ideas?...never did hear the fuel pump thumping though...

[HayZee518]

any kerosene product will absorb moisture and when it does the kerosene breaks down into a brownish sludge. this cover everything in the fuel sump. you'll need to cut off the fuel flow and remove the whole sump tank and clean it out. GUMOUT works the best in dissolving the sludge. Q tips work good here too. a 9/16" wrench or a 14 mm wrench fits the brass gland nut on the fuel line. take everything out of the sump tank but don't disturb the adjustment screw on the float tang. what's happening is fuel is getting to the sump but with all the gunk, the solenoid pump is starving for fuel. I'll betcha the screen in the side of the sump is jammed full of brown junk. 8 bars means no fuel or weak fuel flow. it isn't filling the sump fast enough. BTW before you start the heater, unplug it then plug it in again. this resets the computer. whenever the unit goes into lockout, unplug and plug in the cord again.

[NEWHOPEFARMS]

m21

thanks HZ....so I am taking the sump pump out with the pump attached to the top as one piece?...is it just the 4 base screws that are holding the sump assembly in place?,,,btw I am using the internal tank as the fuel source...not an outside tank...should I try and clean the screen b4 I pull the whole assembly or is taking the sump assembly out and disassembling it the only way to get all the sludge issue resolved....

thanks


Jerry

[Bryand]

You might want to check and make sure the black hose from the air pressure switch to the blower is clear and also the copper tube going into the blower. It could be that a mud dobber has clogged it. Also a common mistake is that the yellow air hose to the exaust pipe is hooked up on the wrong side and is hooked to the extra hole for the exauxt. If so the blower is not pulling in air and fuel pump wont pump. I had one guy that had taken his out for years and cleaned it but one time he hooked the hose up wrong. May not be it but worth checking.

[HayZee518]

you can try just cleaning out the sump filter but in the long run eventually you'll need to clean out the sump. I've owned my new 2400 for three years and each year I had to clean out the brown crap from the sump.
INFO to Bryand - the OP said he cleaned out the intake/discharge lines.

[NEWHOPEFARMS]

m21....

HZ...I am taking the sump off at first light in the morning...it looks like there are just 4 base screws holding it in place....going to get a few cans of gumout 2nite...thanks a bunch...

[Bryand]

HZ...I am taking the sump off at first light in the morning...it looks like there are just 4 base screws holding it in place....going to get a few cans of gumout 2nite...thanks a bunch...

Be careful to look at everything on the inside if you rellay tear it apart. Float, springs,
needle valves. You want to know where they go back.