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Monitor Heater Page TWO


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  • Monitor Heater Page TWO

    The fuel sump is a rectangular shaped bowl with a machined opening in the bottom that contains a micro opening stainless steel and plastic filter. A spring goes on the end into the opening and a plastic “tit” goes against a slight depression in the filter cover. There is also a neoprene gasket under this cover. On the external fuel bowl is a large screw. Removing this bleeds out the fuel left in the bowl after you shut off the tank fuel supply. Make a channel out of aluminum foil and empty the fuel into a very shallow bowl. The monitor 20, 40 and 41 have a mechanical fuel lockout. It is a piece of stamped metal that pivots on a bearing with a spring attached to its top and bottom. It is meant to toggle over center and has a pawl which contacts the needle valve to shut it preventing more fuel from entering the sump. It is actuated by the fuel sump float. Not enough of fuel, the toggle locks out, too much fuel the toggle locks out. There is an adjustment screw on the springy like tang on the float which can be adjusted for a fine point for fuel flow and shut off. The needle valve has a viton or rubber tip which seals against the brass seat in the assembly.
    The solenoid pump operates off a transistorized controller made by TRISAN LTD. Two wires go to the pump, three wires come from the computer to the controller. The two outside wires have 120 volts on them, the center comes off the fuel solenoid relay on the computer board. The controller pulses the solenoid pump. The solenoid pump has its own built in filter screen. Replacement for the pump costs 146.50 from a monitor parts supplier. The controller and pump are sold as a matched unit.

    This is a modified vacuum unit. It impeller looks just like a vacuum cleaner impeller but its only a single stage impeller. A vacuum has multiple stages. It sucks in air from the center and blows it outward within the housing through a rubber elbow and aluminum ducting to another rubber elbow to the combustion pot connection. The air entering the combustion pot comes through those super small openings around the pot. The flow of air vaporizes the fuel so it burns more efficiently and also causes an air flow for exhausting the heated gases to the outside through the center pipe in the dual exhaust tube. There is a solenoid operated flapper damper that opens when the heater starts to combust the fuel. There is a 3 and ½ minute purge cycle before the fuel ignites.
    When the blower starts and sounds like a jet engine winding out, it’s a sign that the bearings are going. When you get the motor apart you can use a bearing puller to get the old bearings off. Purchase new bearings NOT from monitor. Get some American made bearings FAFNIR, SKF NDK. Press them on with a small arbor press don’t bang them on with a hammer and deep well socket.

    No fuel
    No flame
    Shorted flame rod

  • #2
    Monitor Heater - Fuel sump

    This white metal receptacle is where your kerosene goes in. On the left bottom side is a flare connection for the fuel. Cast into the bottom right is a chamber where the fuel filter goes. Two phillips screws hold a metal plate and neoprene gasket. On the upper left part is a large screw that when removed bleeds out the kerosene in the fuel sump.
    Disconnect two wires from the solenoid pump, remove the kerosene tube from the top of the pump. Remove two philips screws from metal plate and lift out the pump. Inside you will see the float and needle valve. Remove two screws and the float will come out. Don't lose the metal pin for the float. There is a piece of nylon that holds the lockout reset lever - pull up on it to disengage the lever. Remove the spring's hook on the lockout toggle. Make a drawing of how the needle valve goes into its seat. If put in backwards it'll stay open and will flood the sump. The lockout toggle unsnaps from the left bearing and then just comes out. Use Q tips and some carberator cleaner like GUMOUT to clean all the junk from inside the sump. The brass needle valve seat doesn't come out. Inside near the bottom are two slots for the fuel to go into the sump proper. make sure these are clean. The hole in the brass seat goes into the filter chamber. If the needle valve rubber is missing or eaten up get a new one. On a spring like metal piece on the float is an adjustment screw. Unless you have to move it DON'T! This is a critical adjustment and adjusts the point at which the lockout actuates. Too far in either direction you could flood out the sump or not have enough of fuel in the sump and the toggle will lock out the mechanism. When you are done cleaning put it back together and make sure the needle goes in the right way.