Lanair HI320 - Manual (Page 51)

SECTION 17 CONTINUED
17.5 Vacuum gauge reading hints:
Low to normal reading, 1-6 inches HG.
1. Pump operating properly.
2. Fuel being used has a low viscosity.
a. Fuel oil is being used.
b. Fuel is at room temperature (warm).
c. High level of gasoline in the fuel (use approved fuels only).
17.6 Vacuum gauge reading hints:
High reading, 7 inches of HG, or more.
1. Fuel being used has to high of a viscosity.
a. Fuel is too cold.
b. Fuel contains gear lubes (use approved fuels only).
2. Suction line strainer dirty or plugged.
3. Pick-up tube strainer dirty or plugged
4. Check valve installed wrong or stuck.
17.7 Vacuum reading hints:
1. Reading fluctuates (jumps).
2. Vacuum leaks in the suction side of the piping to the pump.
3. Low fuel level in the tank.
17.8 Burner fuel pressure gauge reading hints:
1. Fuel gauge fluctuates (jumps).
a. Water/anti freeze in fuel.
b. Air in fuel, refer to Section 17, Flow Chart #2.
c. Quad ring seal for the nozzle may be damaged.
d. Seal in adaptor block may be worn or damaged.
e. Fuel pressure regulator seal leaking or dirty.
f. Suction line strainer plugged or dirty.
2. Reading gradually decreases.
a. Fuel pump output decreasing.
b. Fuel viscosity decreasing.
c. Orifice in nozzle is wearing.
3. Reading gradually increases.
a. Fuel pump output increasing.
b. Fuel viscosity increasing (cold fuel, and/or gear lube).
c. Orifice in nozzle is becoming plugged.
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