Manifold Pressure Gauge - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
TABLE X-VII. MAGNETIC COMPASS (cont.)
Cause
Trouble
Remedy
Card sticks.
Card does not move
when compensating
screws are turned.
Altitude compensating
diaphragm collapsed.
The gears that turn
compensating magnets
may be stripped.
Replace or repair
instrument.
Replace or repair
instrument.
Compass swings
erratically when
radio transmitter
is keyed.
Normal.
10-48. MANIFOLD PRESSURE GAUGE.
10-49. GENERAL. The manifold pressure gauge is a vapor proof, absolute pressure type instrument.
Pressure from the intake manifold of the engine is transmitted to the instrument through a line. A pointer
indicates the manifold pressure available at the engine in inches of mercury.
10-50. TROUBLESHOOTING.
TABLE X-VIII. MANIFOLD PRESSURE INDICATOR
Trouble
Cause
Remedy
Excessive error at
existing barometric
pressure.
Excessive error when
engine is running.
Sluggish or jerky
pointer movement.
Pointer shifted.
Line leaking.
Defective instrument.
Restricted filter
element.
Replace instrument.
Tighten line con-
nections.
Replace instrument.
Replace filter.
Dull or discolored
marking.
Age.
Replace instrument.
Incorrect reading.
Moisture or oil in
line.
Disconnect lines and
blow out.
Restricted filter
element.
Replace filter.
Broken or loose
cover glass.
Vibration or excessive
pressure.
Replace glass and
reseat case.
Reissued: 9/23/80
INSTRUMENTS
3B16