COOLING (cont.)
D. Servicing of Air Conditioner
The detection of system malfunction depends on the mechanic’s ability to interpret gauge pressure
readings into system problems. A system operating normally will have a low side gauge pressure
reading corresponding with the temperature of refrigerant evaporating in the evaporator, allowing for a
few degrees temperature
rise
due to loss in the tube walls and fins. The high side will have a gauge
pressure corresponding with the temperature of the refrigerant condensing in the condenser, allowing
for a few degrees temperature
drop
due to loss in the tube walls and fins.
Any deviation from normal indicates a malfunction within the system due to a faulty control device,
obstruction, defective part, or improper installation.
Detection of system malfunction is made easier with the knowledge that the temperature and pressure
of Refrigerant 12 is in close proximity between the pressures of twenty and eighty pounds per square
inch (psi). A glance at the Temperature-Pressure Chart 2 will show that there is only a slight variation
between the temperature and pressure of the refrigerant in the lower range.
It is correct to assume that for every pound of pressure added to the low side, a temperature increase of
about one degree Fahrenheit takes place. For instance, a pressure of 23.8 on the chart indicates a tem-
perature of 24 F. A change of pressure of almost one pound to 24.6 psi gives us a temperature increase
to 25 F.
— NOTE —
For each 1,000 feet of elevation above sea level, the gauge
readings will be about one inch of mercury or 1/2 psi higher
than the chart indicates.
It must be pointed out that the actual temperature of the air passing over the coils of the evaporator
will be several degrees warmer allowing for a temperature rise caused by the loss in the fins and tubing
of the evaporator.
The importance of a seasonal check up of the air conditioning system should be brought to the atten-
tion of the customer whenever possible. A thorough check of the system performed in a methodical
manner will reveal trouble the customer is often not aware of. Locating and repairing the trouble early
will usually result in savings to the customer both in time and additional troubles that too often result
from neglect.
A Performance Test of the system is the only positive way in which the complete system can be
checked for efficient operation. The air conditioning system should be given this test before work is
begun on the system whenever possible, however, if the system is completely inoperative, repairs must
be performed before the system can be properly tested. The test can uncover further work that must be
performed before the system is brought to its full operating efficiency.The Performance Test should
always be performed after repair work has been done and before the aircraft is released to the cus-
tomer. The serviceman performing this test carefully will insure that the repairs have been properly
performed and that the system will operate satisfactorily.
PIPER AIRCRAFT
PA-32R-301/301T
MAINTENANCE MANUAL
21-50-00
Page 21-16
Reissued: July 1, 1993
1H23
Summary of Contents for PA-32R-301T SARATOGA S
Page 26: ...CHAPTER 4 AIRWORTHINESS LIMITATIONS 1C1 ...
Page 29: ...CHAPTER 5 TIME LIMITS MAINTENANCE CHECKS 1C4 ...
Page 53: ...CHAPTER 6 DIMENSIONS AND AREAS 1D6 ...
Page 64: ...CHAPTER 7 LIFTING AND SHORING 1D21 ...
Page 68: ...CHAPTER 8 LEVELING AND WEIGHING 1E1 ...
Page 72: ...CHAPTER 9 TOWING AND TAXIING 1E5 ...
Page 76: ...CHAPTER 10 PARKING AND MOORING 1E9 ...
Page 80: ...CHAPTER 11 REQUIRED PLACARDS 1E13 ...
Page 92: ...CHAPTER 12 SERVICING 1F1 ...
Page 126: ...CHAPTER 20 STANDARD PRACTICES AIRFRAME 1G17 ...
Page 127: ...THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 139: ...CHAPTER 21 ENVIRONMENTAL SYSTEMS 1H5 ...
Page 188: ...CHAPTER 22 AUTOFLIGHT 1J7 ...
Page 193: ...CHAPTER 23 COMMUNICATIONS 1J12 ...
Page 203: ...CHAPTER 24 ELECTRICAL POWER 1J22 ...
Page 263: ...CHAPTER 25 EQUIPMENT FURNISHINGS 2A13 ...
Page 269: ...CHAPTER 27 FLIGHT CONTROLS 2A20 ...
Page 332: ...CHAPTER 28 FUEL 2D11 ...
Page 363: ...CHAPTER 29 HYDRAULIC POWER 2E18 ...
Page 404: ...CHAPTER 30 ICE AND RAIN PROTECTION 2G16 ...
Page 470: ...CHAPTER 32 LANDING GEAR 3A13 ...
Page 550: ...CHAPTER 33 LIGHTS 3D24 ...
Page 562: ...CHAPTER 34 NAVIGATION AND PITOT STATIC 3E12 ...
Page 582: ...CHAPTER 35 OXYGEN 3F8 ...
Page 604: ...CHAPTER 37 VACUUM 3G6 ...
Page 616: ...CHAPTER 39 3G18 ELECTRIC ELECTRONIC PANELS MULTIPURPOSE PARTS ...
Page 620: ...CHAPTER 51 STRUCTURES 3G22 ...
Page 636: ...CHAPTER 52 DOORS 3H14 ...
Page 650: ...CHAPTER 55 STABILIZERS 3I4 ...
Page 662: ...CHAPTER 56 WINDOWS 3I16 ...
Page 670: ...CHAPTER 57 WINGS 3I24 ...
Page 688: ...CHAPTER 61 PROPELLER 3J18 ...
Page 704: ...CHAPTER 70 STANDARD PRACTICES ENGINES 3K10 ...
Page 708: ...CHAPTER 71 POWER PLANT 3K14 ...
Page 737: ...CHAPTER 73 ENGINE FUEL SYSTEM 4A13 ...
Page 749: ...CHAPTER 74 IGNITION 4B1 ...
Page 783: ...CHAPTER 77 ENGINE INDICATING 4C11 ...
Page 793: ...CHAPTER 78 EXHAUST 4C21 ...
Page 801: ...CHAPTER 79 OIL 4D5 ...
Page 805: ...CHAPTER 80 STARTING 4D9 ...
Page 819: ...CHAPTER 81 TURBINES 4D23 ...
Page 833: ...CHAPTER 91 CHARTS WIRING DIAGRAMS 4E13 ...