TEST CHAMBER ASSEMBLY, MODEL 452
UNIT MAINTENANCE - CONT
INSPECTION PRIOR TO DISASSEMBLY - CONT
If test chamber will not maintain high altitudes with CLIMB/FALL/COCK switch in
CLIMB position, there is a leak in the pneumatic system. Check all compression
nuts for tightness with the fingers. DO NOT USE WRENCHES. Carefully
examine gasket for flaws or damage and replace, if necessary. If the chamber
still will not maintain altitude, send the chamber back to depot for repair.
When disassembling the test chamber, use care to prevent scratching the
altitude chamber. Be careful not to damage mating surface of altitude chamber
when removing damaged gasket.
1. Remove damaged altitude chamber gasket (30) by carefully pulling gasket away from altitude
chamber. A putty knife or similar tool may be used to aid in gasket removal.
2. If replacement is required, peel off identification decal (1) from carrying case (2),and from
control housing (6), WARNING decal (5), FUNCTIONS decal (7), and CONNECTIONS decal
(15). Retain identification decal (1).
3. If replacement of air compressor (13), vacuum pump (14) or altimeter (26) is necessary,
remove four screws (18) holding the housing panel (19) to the control housing (6).
Connection strip (17) mounted inside control housing (6) contains all electrical connections
from the input power and various components. The connections are identified on
connections decal (15) found inside housing panel (19)
4. Unfasten and detach electrical connector (16) from altimeter (26). Unscrew compression nut
(21) and disconnect tubing (22) from elbow (20).
5. Remove three screws (27) and lift altimeter (26) from control housing (6).
Observe orientation of elbow (20) to aid in assembly.
6. If replacement altimeter (26) has no elbow (20) attached, it will be necessary to transfer
elbow from the unit being removed to the replacement.
No sealant is used with elbow (20). An o-ring packing (23), located under back-
up washer (24) and lock nut (25) performs this function. Make sure not to lose or
damage this packing.