Piper Arrow IV, Maintenance Manual

Page: 134 / 752

SPECIAL SERVICING PROCEDURES.
The air conditioning system should be serviced by a qualified shop with trained personnel. The following
procedures and precautions should be observed:
The efficiency of this system depends upon the pressure-temperature relationship of pure refrigerant. As
long as the system contains only pure refrigerant plus a specified amount of compressor oil (which is mixed
with the refrigerant), it is considered to be chemically stable. Foreign materials within the system will affect
the chemical stability, contaminate the system, and decrease its efficiency.
1. GENERAL REFRIGERATION SYSTEM PROCEDURES.
A. REFRIGERANT SAFETY PRECAUTIONS.
(1) Refrigerant 12 (commonly known as R-12 or “Freon” 12) is odorless and colorless in either
the liquid or gaseous state. R-12 for charging refrigeration systems is supplied in pressurized
containers (approx. 70 psi at 70°F) in liquid form. Since this material is essentially inert at
room temperatures the dangers are primarily associated with the pressure and the refrigeration
effects of the release and subsequent evaporation of this pressurized liquid.
(2) Wear suitable eye protection when handling R-12 due to the possibility of freezing of the eye
if contacted by escaping liquid refrigerant. If liquid R-12 does strike the eye, the following
actions should be taken:
(a)
DO NOT RUB THE EYE.
(b) Splash large quantities of cool water into the eye to raise the temperature.
(c) Tape on an eye patch to avoid the possibility of dirt entering the eye.
(d) Rush to a physician or hospital for immediate professional aid.
(e) DO NOT ATTEMPT TO TREAT IT YOURSELF.
(3) If liquid R-12 strikes the skin frostbite can occur. Treat with cool water and protect with
petroleum jelly.
(4) Do not discharge large quantities of R-12 into closed rooms. It may displace most of the air in
the room and this could cause oxygen starvation. Gaseous R-12 is heavier than air and flows
to the bottom of a container.
(5) Do not discharge R-12 into an open flame or onto a very hot surface (500° F+). Poisonous
phosgene gas is generated by the action of the heat on the refrigerant.
(6) Do not apply direct flame or other high heat source to a R-12 container due to the high
pressures which will result. If any heating is done to R-12 containers the container pressure
should be monitored and kept below 150 psi.
B. SYSTEM SERVICING PRECAUTIONS.
(1) Systems should be discharged slowly to prevent the escape of liquid refrigerant and the loss of
the lubricating oil.
(2) Systems should not be left open to the atmosphere when discharged. Moisture and other
contamination may enter and damage open systems.
(3) Never introduce anything but pure refrigerant and refrigerant oil into a system.
(4) Keep refrigerant oil containers tightly sealed and clean to prevent absorption of moisture or
other contamination.
(5) Use only approved refrigeration oil in the compressor. If any doubt exists about the cleanliness
of the compressor oil, replace it with new oil.
(6) Never reuse oil removed from the system. Discard it.
21-50-03
Page 21-15
December 1, 1978
1F14
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL