Fault Isolation; Air-Conditioning System Troubleshooting; Early Config - MD Helicopters MD Explorer Servicing And Maintenance

1. Air−Conditioning System Troubleshooting
(Ref. Figure 101 thru Figure 103)
The troubleshooting procedures in Table 101
are air-conditioning system faults which
possibly can occur.
Fault
Air Condition does not
operate when the COOL
LOW or COOL HI selection
is made on the Utility Control
Panel during normal engine
operation.
(See Note 1)
MD Helicopters, Inc.
Rotorcraft Maintenance Manual
AIR−CONDITIONING SYSTEM

FAULT ISOLATION

Table 101. Air−Conditioning System Troubleshooting
Probable Cause
Circuit breaker COMP
(CB17) open.
Defective air condition
disable relay K7−5.
Open wire between relay
K7−5−X2 and P104−ZF
(on the IIDS).
Defective compressor
solenoid.
Defective time delay relay
K7−3/4.
System pressure is low.
Defective low pressure
switch.
System pressure is high.
Defective IIDS.
Troubleshooting tables are used with system
schematics, electrical wiring diagrams,
serviceable checks, and also refer to other
procedures in this manual.
Wiring diagrams are available in the Rotor­
craft Maintenance Manual CSP-900RMM-3
(ref. Section 98-40-00).
Corrective Action
Replace or reset COMP circuit
breaker (CB17) as necessary.
Replace the relay.
Do a test on the wires for a
serviceable condition. Make
repairs as necessary.
Replace the compressor.
Replace the time delay relay.
Service the air conditioning
system.
A leak in the air conditioning
system. Repair as necessary.
Replace the low pressure
switch.
Defective thermostatic
expansion valve (TXV).
Replace the valve.
Condenser is dirty, clean as
necessary. Remove blockage
from the air inlet as necessary.
EARLY CONFIG −
Condenser fans do not operate.
Repair or replace as necessary.
Replace the IIDS.
21-50-00
CSP−900RMM−2
Ref. Section
96−00−00
96−00−00
20−60−00
21−50−00
96−00−00
12−00−00
12−00−00
21−50−00
21−50−00
21−50−00
21−50−00
95−30−00
Page 101
Revision 34