Troubleshooting; Gyro Pressure Gauge; General; Pressure Regulating Valve - Piper SENECA II Service Manual

10-5. TROUBLESHOOTING.

See Table X-I.

10-6. GYRO PRESSURE GAUGE.

10-7. GENERAL.

The gyro pressure gauge monitors the regulated gyro system pressure. The gauge is mounted in the
lower right side of the instrument panel and is calibrated in inches of mercury. The gauge has two red
malfunction indicator buttons.
10-8. TROUBLESHOOTING.
See Table X-I.

10-9. PRESSURE REGULATING VALVE.

10-10. GENERAL.
The pressure regulating valves regulate gyro system pressure at 4.8 to 5.1 inches of mercury for S/N up
to 34-8170091 inclusive or 4.8 to 5.2 inches for S/N 34-8170092 and up. The regulating valves are
mounted on the aft side of the firewall, and are adjustable to provide the correct system pressure.
Incorporated in each valve is an electrical switch that completes a circuit to provide a visual display on
the annunciator panel whenever gyro air pressure is insufficient.
10-11. TROUBLESHOOTING. (Refer to Table X-I.)
10-12. ADJUSTMENTS TO PRESSURE REGULATOR. (Refer to Figure 10-1.)
a. Remove nacelle cover to gain access to the pressure regulator.
b. For S/N up to 34-8170091 inclusive:
Operate both engines at 2575 RPM; the gyro pressure gauge reading should be 4.8 to 5.l inches of
mercury.
NOTE: The pressure indicator with one engine at a time running at 2000 RPM should be within .1
inches of mercury of each other. With both engines operating at 2575 RPM, the reading
should not exceed 5.2 inches of mercury.
c. For S/N 34-8170092 and up:
1. Set pressure regulator for one engine at 4.8 to 5.2 inches of mercury with that engine operating
at magneto check RPM and other engine at idle or off.
2. Repeat setting procedure for other engine.
3. After settings are made on both engines, check the pressure readings to be sure that it is within
limits when both engines are operating at mag check RPM.
d. To adjust the regulator, bend the locking tabs on the adjustment screw and adjust the screw as
required to obtain correct gyro pressure.
e. After adjustment is complete, bend tabs to lock screw in place and recheck pressure. Reinstall
nacelle cover.
X - INSTRUMENTS
PIPER SENECA II SERVICE MANUAL
2E12
01/01/09