6. Disconnect filler hose from port, securely replace cap nut on filler valve port,
and set FILL-RUN-DRAIN valve handle to RUN.
7. Replace cover plate on right side of test set.
3-5. EMPTYING SUMPS.
3-6. The two test set fuel filters are equipped with sumps which permit only air to enter
the vacuum and pressure lines to the instruments.
If the oil occupies more than 50 percent
of the total glass area of the sumps, the sumps must be emptied. To empty the sumps,
proceed es follows:
1.
2.
3.
4.
gasket.
5.
Open test set panels to gain access to interior.
Loosen bottom screw of sump bracket, remove sump, and empty oil from sump.
Clean bowl and filter with Varsol in accordancewith Federal Specification TT-T-291.
Replace Sump and secure bottom screw tightly to prevent leakage through sump
Operate test set for maximum vacuum using altimeter and for maximum pressure
using fuel pressure gauge. Refer to paragraph 2-5 for operating procedures.
6. If maximum vacuum or pressure is not obtained in step 4, leakage probably exists
at sump gasket. Tighten bottom screw of sump to produce a complete seal.
7. Turn off test set. Replace panels which were removed in step 1.
3-7. ADJUSTMENT OF SAFETY RELIEF SYSTEM.
3-8. All instruments are protected by a safety relief system which operates if excessive
pressure or vacuum is applied to any instrument. Five bellows assemblies are used, two
for vacuum and three for pressure. (See figure 3-1.) If excessive pressure or vacuum
occurs, the applicable bellows actuate an associated microswitch which in turn applies
operating power to two solenoid valves.
One valve is located in the pump pressure line and
one is located in the vacuum line.
When the valve operates, the pressure and return lines