Lanair MXD300 - Manual (Page 29)

Section 10 - Priming The Fuel Pump
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25
Figure 8
Remove two yellow wires
Figure 9
Install jumper wire
Priming The Fuel Pump
1.
2.
3.
4.
5.
6.
7.
8.
9.
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11.
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14.
The fuel level in the supply tank must be
above the check valve on the pick-up tube.
Remove the bowl of the suction line strainer,
and fill with clean fuel. Replace the strainer
bowl.
Remove the two yellow wires from the F-F
terminal on the oil primary control. Install a
jumper wire between the F-F terminals (see
Figs. 8 & 9).
Adjust the air filter/regulator on the heater to
12-15 PSI.
Remove the fuel supply line from the burner,
and position a container to catch the fuel.
When using the by-pass regulator, back the
thumb screw out (CCW) on the by-pass
regulator until it is free, the turn (CW) two
turns to seat the diaphragm.
Loosen the bleeder screw on the pump one
turn, and attach a piece of 3/16” ID clear plastic
tubing. The tubing should be long enough to
allow the fuel to be returned to the tank.
Turn the room thermostat above room
temperature, or to the “ON” position.
Momentarily disconnect one end of the
jumper wire at the F-F terminals on the oil
primary. The fuel pump will now start.
Observe the clear tubing attached to the bleeder screw on the pump. When a steady
stream of fuel (no air bubbles) flows close the bleeder screw. Remove the tubing from the
bleeder screw.
Observe the end of the fuel supply line that is disconnected from the burner. Allow a
steady stream (no air bubbles) of fuel to flow into the container for several minutes. This
will flush any debris from the fuel line that could potentially plug the nozzle. The vacuum
gauge reading should not exceed 5” HG of vacuum.
Turn the room thermostat below room temperature or “OFF”. The fuel supply pump will
now stop.
Reconnect the fuel supply line to the burner.
Remove the jumper wire from the F-F terminals on the oil primary control, reattach the
yellow cad cell wires.