Fuel Filter; Pump Pressure Adjustment - Newmac NM-75K Operating Instructions Manual

FUEL FILTER

• Clean or replace twice per heating season or as needed.
• Remove side cover screws using medium Phillips screwdriver.
• Remove side cover.
• Pull fuel line off fuel filter neck.
• Turn fuel filter counterclockwise 90 degrees, pull, and remove.
• Wash fuel filter with clean fuel and replace in tank.
• Attach fuel line to fuel filter neck.
• Reinstall side cover.
• Open side cover screws using medium Phillips screwdriver.
• Disconnect switch wires from power switch and remove side
cover.
• Pull fuel line off fuel filter neck.
• Pull fuel line.
• Turn fuel filter clockwise 90 degrees and pull to remove.
• Wash fuel filter with clean fuel and replace in tank.

PUMP PRESSURE ADJUSTMENT

• If model is not equipped with a built in air pressure gauge, remove
pressure gauge plug from end of filter cover.
• If model is not equipped with a built in air pressure gauge, install
accessory pressure gauge.
• Start heater.
• Allow motor to reach full speed.
• Adjust pressure.
• Turn relief valve clockwise to increase pressure.
• Turn relief valve counterclockwise to decrease pressure.
• Set pump pressure to correct pressure for each model.
Model
NM-75K
NM-125K
NM-175K
NM-215K
• Stop heater. If accessory pressure gauge is being used, remove
pressure gauge.
• Replace pressure gauge, and plug in end of filter cover. NOTE: USE
ONLY ORIGINAL EQUIPMENT REPLACEMENT PARTS. Use of alternate
or third party components will void warranty and may cause an
unsafe operating condition.
Maintenance
Pump Pressure
4.7PSI
4.9PSI
4.9PSI
5.5PSI
Pressure
Gauge
Plug
Adjusting Pump Pressure
NM-75K
Relief
Valve
-12-
Circuit Board
Photocell
Install Photocell
Photo Cell Wire
Fuel Filter
Fuel Line
Screw
Side Cover
Power Switch
Power Switch Wire
Adjusting Pump Pressure
NM-125K, NM-175K, NM-215K
Switch Wires
Photocell
lens
1) Incorrect
2) Correct
Circuit
Board