1811D INSTRUCTION MANUAL
56-101-00164 Rev. F
SECTION 4
Apr / 19 / 13
Page 27 of 38
SECTION 4: VALVE LEAK TEST
1. METERING VALVE ADJUSTMENT PROCEDURE
Note: The following procedure is also released as IM150 (dated 7/6/88.)
A. VALVE LEAK TEST
Caution: Before performing the Valve Leak test, inspect for system or instrument
leakage. (Refer to the appropriate Aircraft Maintenance Manual for
information and proper procedure.)
Note: Read this section in its entirety (parts 1 and 2), before performing test since all
these steps must be done in combination when performing valve adjustments.
B. PRESSURE VALVE TEST
(1) Close all valves except VACUUM VENT (#4).
(2) Plug PRESSURE (#C) and VACUUM (#F) ports (single action pumps only).
(3) Pressurize PRESSURE TANK (#B) to 15 PSI.
(4) Monitor AIRSPEED INDICATOR (#D) for one (1) minute.
(a) If an increase in airspeed is seen, continue to monitor for an additional five
(5) minutes.
(b)
If during the monitoring period the airspeed increase exceeds five (5) knots, a
leak exists at the PRESSURE valve (#1).
(5) Correct leak before continuing. Refer to subsection 2. RESETTING NEEDLE
VALVE POSITIVE STOP.
C. PRESSURE VENT AND CROSSBLEED VALVE TEST
(1) Close all valves except VACUUM VENT (#4).
(2) For single action pumps, plug the PRESSURE (#C) and VACUUM (#F) ports.
Caution: Do not over pressurize the airspeed indicator.
(3) Apply enough pressure to the PRESSURE TANK (#B) to provide full scale travel of
the AIRSPEED INDICATOR (#D).
(4) Gently open the PRESSURE valve (#1). Increase the airspeed to full scale.
(a)
Close PRESSURE valve (#1).
(b) Monitor the AIRSPEED INDICATOR (#D) for one (1) minute. If there is a
decrease of more than two (2) knots, a leak exists at the PRESSURE VENT
(#2) or CROSSBLEED (#3) valves.