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Monitor heater 441 pump not coming on


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  • Monitor heater 441 pump not coming on


    I have a Monitor 441 that will not light. pot is getting hot,blower(lower right side) is running.checked the fire rod clean. took the line off the pump and no fuel pumping. tried to check the voltage at the pump none? don't know what it should be? tried AC 120V setting and DC 20V setting. Question when the unit is running should i feel air outside coming out of the center tube? unit worked fine in last May. replaced filter(outside) checked inside filter all OK. checked fuel level in the unit was at the line on the outside of the pump tank.(took pump off looked inside) So where do look now? also checked Ohms on pump was around 600.(wires off). Please any help would be great.
    Thank you...TOM

  • #2

    If the combustion fan is running, is the air flow proving switch closed?
    Are all the normally closed devices IN FACT CLOSED?
    If any of the safety devices are NOT closed, the fuel pump will not work.
    The igniter turns on the instant the power comes on. The combustion pot should be warm, not hot!
    Try turning off the unit. Un plug it from the outlet, then plug it back in and start a heat cycle.
    Get back to us what happened.


    • #3
      fuel pump issue

      The fuel pump (wires removed) resistance should be around 565 OHMs. You will have a hard time checking the voltage on the main board, as it is a "pulsing" voltage. To read it correctly you need a very expensive meter. I suspect you have a Air Safety Switch issue, it's doing it's job. If the combustion blower is restricted in any way the fuel pump will not come on. Check the flue pipe, both exhaust (inside) and air (outside) pipe for obstructions. Of course the blower has to be turning for anything to happen in the first place.



      • #4
        Thanks i will check all the pipes for maybe a bee's nest??..the blower fan is running(lower right side). and the heater pot is getting warm not hot.(sorry i said hot before) also going to check that 2 amp fuse on the MB.
        Thank you guys! will get back to you tomorrow what i find.


        • #5
          air flow switch

          check the rubber hose that goes from the blower shroud to the air flow proving switch. it usually cracks at the nipple going into the switch.
          use some vacuum hose for a car to replace it if its cracked.


          • #6
            found one problem..

            Well been sick with my back.Better now. OK found the intake hose full of water! so now the pump works.But it fires up and runs about 2 mins half on the burner meter then stops burning burner lights go out.
            Question it feels like the pipe going into the burner pot has broke from the pot.would that make it act this way? sure i need a welder or new pot..

            Thank you guys!


            • #7
              water in intake hose.

              I looked and the pipe coming in is tilted up just a little.going to put something over it to stop rain getting in.(some tin) checked the little black hose coming off the fan unit clear and no cracks. still heats only for about 2 mins then burner turns off.


              • #8
                Fuel pipe in burner is broke.

                Hello again. Yes the fuel pipe part of the burner pot the weld is broke.(darn)I pulled on the pipe and it came out. Maybe that would make the burner stop after 2 mins of burn? how do i get that pot out? I see a plate where the glass window is?

                Thanks guys..


                • #9
                  fuel nozzle

                  with that fuel line not connected to the nozzle fuel will leak out before entering the combustion pot.
                  like you said, you'll need to get a new pot or have the nozzle tig welded back into the pot.

                  to take out the pot, you'll need a long phillips screwdriver

                  the pot and heat exchanger will come out as a unit. there's four or five screws that hold the pot to the heater case. underneath the pot is a gasket. don't break this. the air inlet is a rubber elbow below the pot. remove the spring clamp and remove the elbow.

                  look how its fastened and remove any external screws that hold the pot to the heater.

                  if you flip the pot over there's more screws between the shell and the inner sleeve. take these out and the sleeve should come out.

                  while you got this out clean all the holes around the inner sleeve. this is where the fuel vapor and air comes out to give you that nice blue flame.


                  • #10
                    Originally posted by woolfman1 View Post
                    Hello again. Yes the fuel pipe part of the burner pot the weld is broke.(darn)I pulled on the pipe and it came out. Maybe that would make the burner stop after 2 mins of burn? how do i get that pot out? I see a plate where the glass window is?

                    Thanks guys..
                    You might want to read this or print it. Think it will help:


                    • #11
                      broke weld on burner pot

                      Hi, thanks for all your help. and the fuel line is hooked up but i can feel the weld is broke at the burner. you do get heat for maybe 2 mins then stops.


                      • #12
                        inlet - exhaust

                        the instructions for installing the heater specifically states to install the inlet - outlet pipe at a downward slope of about a quarter inch where it goes through the wall.
                        how come yours is going uphill?


                        • #13
                          pipe going up hill

                          Well? the guy from the store installed it that way. but i can fix it.
                          Question with that fuel pipe weld broke would that make the unit only heat about 2 mins? or am i looking at more bad parts? guess i need to check the out going pipes for water?

                          Thank you..


                          • #14

                            the service guy ought get shot! I just hope the rest of his installs were ok.
                            with that nozzle not welded to the inside pot, fuel leaks down into the space between the inner and outer sleeve of the combustion pot. by rights the fuel should flow to the burner mat in the center bottom of the inner sleeve. there, it burns and is vaporized and flows upward to the upper holes through the space between the inner and upper part of the combustion pot. when the vapor hits the high heat inside the pot the flames turn blue and further heat the burner ring.


                            • #15
                              Shoot the installer.

                              Thank you HayZee518 your great!

                              I guess it's coming apart soon as my back will let me.(you know how that is) I have a #2 Phillips bit that will go on a 3/8 24" extension. plus i have a 12 inch. I did not see a good flame in the window guess from the air leak the weld broke. Well time for a Celebrex. my back is killing me today its been raining all day here in WNC. going to be 18 Sunday night cold for here. and 30+ winds.
                              Thanks for all the Replies! This is a great forum on monitor heaters.