RJ150-30 / Operations and Maintenance Manual
Mobile Aircraft Air Conditioner
Trailer Mounted, Cool Mode Only
______________________________________________________________________________
SECTION 2 - 2
JANUARY 20, 2004
PAGE 4
Table 2: Air Conditioning Troubleshooting Chart
Fault & Condition
Probable Cause
Test, Check, Remedy
1. Physical conditions not met
Check the following:
- OFF/GEN ON/FAN ON switch
(SW1) set to GEN ON
- VENT/COOL switch (SW2) set
to COOL
- Genset operating
- Blower operating
- Damper control valve open
- Cool potentiometer P1 set to
50% or higher (normally set to
70%)
- Airflow switch (AFS) closed
- Ambient temperature above
50
°
F (10
°
C)
a. Check control power
transformer (T1) fuses (FU1,
FU2, FU3). Replace fuses as
required.
2. Control circuits not
energizing; loss of 24 VAC
control power
b. Verify proper phase monitor
(PM1) operation. Verify 24 VAC
output to controller ETC2
3. Improper cool controller
settings or inoperative controller
(ETC2)
a. Verify ETC2 settings:
- Set Point: 50
°
F (10
°
C)
- Differential: 1
°
F (.6
°
C)
If incorrect, adjust settings.
Refer to Section 2-4
4. Faulty VENT/COOL selector
switch (SW2)
Verify continuity and control
voltage (24 VAC) across SW2.
Replace SW2 as required.
Air conditioner fails to start;
Genset operating normally
5. Faulty ambient air
temperature sensor (RTD2)
Verify continuity across RTD2
connections at cooling controller
ETC2 terminals. Replace RTD2
as required.
a. Check condenser air inlet and
discharge for obstructions.
1. Head pressure too high or
high pressure switch (HPS1) is
open
b. Check for proper condenser
fan motor (M3) operation. If fan
not operating, check trip/reset
switch on motor starter (MS3).
Attempt reset; replace as
required.
Compressor fails to start; genset
operating normally
2. Complete loss of refrigerant
charge
Inspect for refrigerant leak;
repair/replace as required.
