MD Helicopters MD Explorer - Fault Isolation; Heat; Defog System Troubleshooting

CSP−900RMM−2MD Helicopters, Inc.
Rotorcraft Maintenance Manual
Page 101
Revision 24
21-40-00
HEAT / DEFOG SYSTEM
FAULT ISOLATION
1. Heat / Defog System Troubleshooting
(Ref. Figure 101)
The following troubleshooting procedures are a
brief summary of heat/defog system faults
which may be encountered (Ref. Table 101).
Troubleshooting tables should be used with
system schematics, electrical wiring diagrams,
serviceability checks and other detailed
procedures in this and other chapters of the
manual.
Comprehensive wiring diagrams are available
in the Rotorcraft Maintenance Manual
CSP-900RMM-2 (Ref. Section 98-40-00).
Table 101. Heat / Defog System Troubleshooting
Fault Probable Cause Corrective Action Ref. Section
Bleed air on with heat/defog
switch OFF
Defective wiring circuit
between flow control shutoff
valve and utility control
panel.
Test and repair wiring circuit. 20−60−00
Flow control shutoff valve
stuck open.
Remove and replace flow
control shutoff valve.
21−40−00
No heat/defog bleed air with
switch set to ON position.
Defective wiring circuit
between circuit breaker and
flow control shutoff valve.
Test and repair wiring circuit. 20−60−00
Fire/overheat bleed air leak
detection system shut down
heat/defog system through
IIDS.
(See Note)
Find heat/defog bleed air leak
and repair leak.
21−40−10
26−10−10
Defective flow control shutoff
valve.
Remove and replace flow
control shutoff valve.
21−40−00
No cabin heat with switch set
to ON.
Ejector control cable(s)
assembly disconnected, out
of rig, or broken cable.
Adjust control cable for proper
rigging. Replace broken cable.
21−40−00
Ejector produces excessive
amounts of hot air.
Internal ejector failure. Replace heat ejector. 21−40−00
Whistle sound from under
cabin floor with heat/defog
ON. (No system shutdown by
IIDS and IIDS does not
display CAB HEAT Warning).
Bleed air coupling(s) or
tube(s) leaking. (Bleed air
leak not hitting detection
cable to cause IIDS
indication.)
Turn off HEAT switch for
heat/defog system, if sound
stops; repair coupling(s) or
replace leaking air tube.
21−40−00