AirComm Corporation Air Conditioner R134A Service Manual

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 16 
 
4.  COIL CLEANING MAINTENANCE PROCEDURES 
 
A. General 
 
The following procedure is used for cleaning either evaporator or condenser 
coil. 
 B. Tools and Equipment 
 
 
Designation  
Ref. No.  
Qty  
Remarks 
 
 
Vacuum Cleaner  
Comm. Avail.  
1  
None 
 
Coil Cleaner  
Comm. Avail.  
A/R  
Non-acid based 
 
C.  Coil Cleaning Procedure 
1.  Use vacuum cleaner to remove large debris from upstream and 
downstream coil faces. 
2.  Spray coil cleaner on both coil faces.  Wash off with water. 
3.  Allow coil to dry thoroughly prior to additional maintenance. 
  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 17 
 
5.  EXPANSION VALVE REMOVAL AND INSTALLATION 
 
A. General 
 
The following procedure is used to remove or install the air conditioning system 
expansion valve. 
 
B. Tools and Equipment 
 
Designation 
  
Ref. No.  
Qty  
Remarks 
 
Sealant  
ES49000-1  
A/R  
None 
 
Polyolester Oil  
Comm. Avail.  
A/R  
Viscosity ISO 68 
 
C. Expansion Valve Replacement 
1.  Discharge system in accordance with Refrigerant Servicing section. 
2.  Disconnect liquid line from inlet of expansion valve, and cap. Remove the 
thermal sense bulb from its clamp located on the suction tube of the 
evaporator and carefully remove insulation covering bulb. 
3.  Disconnect the fitting that connects the valve to the coil and plug coil 
fitting. 
4.  Install new expansion valve and o-ring (for o-ring fitting systems) in the 
reverse order.  
5.  Lubricate o-ring with polyolester oil or apply sealant to fitting mating 
surfaces prior to assembly. 
6.  Install the thermal sense bulb such that it makes contact with the suction 
tube along its entire length. When viewing the suction tube extruding out of 
the evaporator, the sense bulb should be in the three or nine o’clock 
position (Figure A and B).  Attach the sensor bulb using two zip ties.  
Insulate the bulb and expansion valve thoroughly with insulation (Figure C). 
 
 
  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 18 
 
(Figure A) 
 
(Figure B) 
 
 
(Figure C) 
 
  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 19 
 
6.  COMPRESSOR MAINTENANCE PROCEDURES 
 
A. General 
 
The following procedure is used whenever the compressor is replaced or 
contamination is suspected. 
 
B. Tools and Equipment 
Designation Ref. No. Qty 
Remarks 
None - - None 
 
C. Compressor Replacement 
 
1.  Flush system and replace compressor per the Refrigerant Servicing 
section. 
 
 
  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 20 
 
TROUBLESHOOTING 
 
1. GENERAL 
 
The procedures below present troubleshooting charts for the air conditioning 
system and the compressor.  A diagnoses chart is presented for insufficient air 
conditioning system cooling.  The performance characteristics of an aircrafts 
particular system is dependant upon the design parameters of the systems 
components.  The performance of any one particular system varies with ambient 
temperature and humidity.  The information below presents possible air 
conditioning system problems and solutions. 
 
CAUTION:  Do not operate air conditioning system with condenser air outlet blocked. 
 
2. AIR CONDITIONING SYSTEM DIAGNOSIS CHART 
 
Figure 3 shows a procedure for diagnosing air conditioning system problems.  
Following this procedure will expedite the troubleshooting process. 
  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 21 
 
Figure 3.  Air Conditioning System Diagnosis Chart  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 22 
 
3.  AIR CONDITIONING SYSTEM TROUBLESHOOTING 
 
 CONDITION  
SERVICE 
PRESSURE 
GAUGE READING  
 PROBABLE CAUSE 
CORRECTIVE 
ACTION 
 
INSUFFICIENT 
REFRIGERANT 
CHARGE 
 
Insufficient cooling.  
Bubbles appear in 
sight glass.  
  
SUCTION  
PRESSURE:  below 
normal 
 
DISCHARGE 
PRESSURE:  below 
normal  
 
Refrigerant is low, or leaking 
a little.  
 
1.  Leak test. 
2.  Repair leak. 
3.  Charge system. 
 
Evacuate as necessary 
and recharge system.
 
 
ALMOST NO 
REFRIGERANT 
 
No cooling action.  A 
lot of bubbles or 
something like mist 
appears in sight 
glass.
  
 
 
 
SUCTION  
PRESSURE:  much 
below normal 
 
DISCHARGE 
PRESSURE:  much  
below normal  
 
 
 
Serious refrigerant leak.  
Stop compressor 
immediately. 
 
1. Leak test. 
2. Discharge system. 
3. Repair Leak(s). 
4.  Replace receiver drier, if 
necessary. 
5. Check oil level. 
6. Evacuate and recharge 
system.
 
 
FAULTY EXPANSION 
VALVE 
 
a) Slight cooling. 
Sweating or frosted 
expansion valve outlet. 
 
 
 
b) Insufficient cooling. 
Sweated suction 
line. 
 
 
 
 
 
 
 
c) No cooling. 
Sweating or frosted 
suction line.
  
 
a) SUCTION  
PRESSURE:  below 
normal 
 
DISCHARGE 
PRESSURE:  below 
normal 
 
 
b) SUCTION  
PRESSURE:  above 
normal 
 
DISCHARGE 
PRESSURE:  above 
normal 
 
 
 
c) SUCTION  
PRESSURE: above 
normal 
DISCHARGE 
PRESSURE: below 
normal  
 
a) Expansion valve restricts 
 refrigerant.  Or, expansion 
valve is clogged.  Or, 
expansion valve is 
inoperative.  Or, valve 
stuck closed.  Thermal bulb 
has lost charge. 
 
b) Expansion valve allows  
too much refrigerant 
through evaporator. 
 
Sensing bulb on suction 
line not well insulated or 
properly attached to line. 
 
 
 
c)  Faulty expansion valve.  
 
a) Replace expansion 
 valve. 
 
 
 
 
 
 
 
b) 
1.Check valve for 
operation.  If suction side 
does not show a pressure 
decrease, replace valve. 
2. Check security and 
insulation on sensing bulb. 
 
c) 
1.  Discharge system. 
2.  Replace valve. 
3.  Evacuate and recharge 
system.
  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 23 
 
 
 
 CONDITION  
SERVICE 
PRESSURE 
GAUGE READING  
 PROBABLE CAUSE 
CORRECTIVE 
ACTION 
 
AIR IN SYSTEM 
 
Insufficient cooling.  
 
Sight glass shows 
occasional bubbles.    
SUCTION  
PRESSURE:  above 
normal 
 
DISCHARGE 
PRESSURE:  above 
normal  
 
 
Air mixed with refrigerant in 
system.  
 
 
1. Discharge system. 
2  Replace receiver drier. 
3.  Evacuate and charge 
 system. 
 
 
MOISTURE IN SYSTEM 
 
After operation for a 
while, pressure on 
suction side may show 
vacuum pressure 
reading.  During this 
condition, discharge 
air will be warm.  As 
warning of this, 
reading shows approx 
6 psi oscillation.  
 
 
SUCTION  
PRESSURE:  below 
normal 
 
 
DISCHARGE 
PRESSURE:  above 
normal  
 
 
Drier is saturated with 
moisture.  Moisture has 
frozen at expansion valve.  
Refrigerant flow is restricted.  
 
 
1. Discharge system. 
2.  Replace receiver drier 
 (twice if necessary). 
3.  Evacuate system  
completely.  (Repeat 30 
minute evacuating three 
times.) 
4. Recharge system. 
 
 
FAULTY CONDENSER 
 
Insufficient cooling. 
 
Bubbles appear in 
sight glass of drier. 
 
Suction line is very 
hot. 
 
 
  
 
 
SUCTION  
PRESSURE:  above 
normal 
 
 
DISCHARGE 
PRESSURE:  above 
normal  
 
 
Condenser air or refrigerant 
flow is restricted.  
 
Check condenser for dirt 
accumulation. 
 
Check for refrigerant 
overcharge. 
 
If pressure remains high 
in spite of all above 
actions taken, remove 
and inspect the 
condenser for possible 
oil clogging. 
 
 
HIGH PRESSURE LINE 
BLOCKED 
 
Insufficient cooling.  
 
Frosted high pressure 
liquid line.    
 
SUCTION  
PRESSURE: much  
below normal 
 
DISCHARGE 
PRESSURE:  much 
above normal  
 
 
Drier clogged, or restriction 
in high pressure line.  
 
 
1. Discharge system. 
2. Remove receiver drier 
and replace it. 
3.  Evacuate and charge 
system.
 
  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 24 
 
 
 
 CONDITION  
SERVICE 
PRESSURE 
GAUGE READING  
 PROBABLE CAUSE 
CORRECTIVE 
ACTION 
 
FAULTY 
COMPRESSOR 
 
Insufficient cooling.  
 
 
SUCTION  
PRESSURE:  much 
above normal 
 
 
DISCHARGE 
PRESSURE: much  
below normal  
 
 
Internal problem in 
compressor, or damaged 
gasket and valve.  
 
 
1. Discharge system. 
2. Remove and check 
compressor. 
3.  Repair or replace 
compressor. 
4.  Check oil level. 
5.  Replace receiver drier. 
6.  Evacuate and charge 
system. 
 
 
TOO MUCH OIL IN 
SYSTEM (Excessive) 
 
Insufficient cooling. 
 
 
  
 
SUCTION  
PRESSURE:  above 
normal 
 
 
DISCHARGE 
PRESSURE:  above 
normal 
  
 
 
Too much oil circulates with 
refrigerant, causing the 
cooling capacity of the 
system to be reduced.  
 
 
Refer to Oil Level Check 
for correcting oil level. 
 
 
  
						

							Products, INC. 
TR-134 System Service Manual
 
 
Aug 21/06 
Page 25 
 
4.   COMPRESSOR TROUBLESHOOTING 
  
A. General 
 
The following procedures are used for troubleshooting the compressor. 
 
B. Tools and Equipment 
 
 
Designation  
Ref. No.  
Qty  
Remarks 
 
 
Service Pressure Gauge  
Comm. Avail.  
1  
None 
 
DC Power Supply  
  
A/R  
None 
 
C. Compressor Troubleshooting Procedures 
 
With the air conditioning system operating, do any of the following conditions occur: 
 
NOTE:  Always attach a service gauge set to the system prior to trouble shooting, 
to insure proper refrigerant charge is present. 
 
Trouble
      Probable Cause   Correction 
1. Unusually high 
suction pressure 
with low discharge 
pressure. 
 
 
2. Unusually low 
suction and 
discharge 
pressure. 
 
3. High compressor 
discharge 
pressure. 
 
 
 
 
 
4. Rough running. 
 
 (a) Internal problem 
with compressor 
body. 
(b) Faulty Expansion 
valve 
 
System or 
compressor Leak. 
 
 
 
(a) Air exhaust duct 
collapsed or 
restricted. 
(b) Refrigerant  
overcharge. 
 
 
 
Internal compressor 
problem. (a) Replace 
compressor. 
 
(b) Replace expansion 
valve 
 
Repair leak or replace 
compressor. 
 
 
 
(a) Inspect/replace 
exhaust duct. 
(b) Discharge 
refrigerant until only 
occasional bubbles are 
present in sight glass. 
 
 
Replace compressor.