TM 1-1500-204-23-1
Table 9-4. Troubleshooting Pneumatic Deicing Systems
Trouble
Probable cause
Remedy
1. Pressure gauge oscillates
a. Faulty lines or connections.
Repair or replace lines.
Tighten loose connections.
b. Deicing boots torn or punctured
Repair faulty boots.
c. Faulty gauge
Replace gauge.
d. Faulty air relief valve
Adjust or replace relief valve.
e. Faulty air regulator
Adjust or replace regulator.
2. Pressure gauge oscillates;
a. Vacuum check valves installed
Reinstall correctly.
peaks at a specified pressure
improperly
while instrument vacuum
gauge shows no reading
b. Vacuum relief valve Improperly
Adjust or replace valve as
adjusted or faulty
necessary.
c Faulty lines between pump and
Tighten, repair, or replace faulty
gauge
lines or connections.
3. Pressure gauge shows no
a. Faulty pressure gauge line
Repair or replace line.
pressure while vacuum gauge
shown normal reading.
b. Faulty pressure gauge
Replace gauge.
c. Pressure relief valve faulty
Adjust or replace as necessary.
d. Pressure regulator faulty
Adjust or replace as necessary.
4 Cycling period irregular
a. Loose or faulty tubing and
Tighten, repair, or replace as
connection
necessary.
b. Boots torn on punctured
Repair faulty boots.
c. Faulty electronic timer
Replace timer.
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