c. The refrigeration system must by pumped down and in some actions totally discharged
before any maintenance is performed on system components. Be sure that all refrigerant in the
section of the system that you are working on has been discharged. Read and understand all
Instructions prior to attempting repairs. Leak testing and dehydrator replacement are required
after any system component has been removed and replaced. The section of the system that was
opened must be evacuated before it is charged. The system must be properly charged to function
is used in this equipment.
or severe injury may result if personnel fail to observe safety precautions.
Use great care to avoid contact with liquid refrigerant gas being discharged
under pressure. Sudden and irreversible tissue damage can result from
freezing. Wear thermal protective gloves and a face protector or goggles
in any situation where skin-eye-contact is possible. Prevent contact of
refrigerant gas with flame or hot surfaces. Heat causes refrigerant to
break down and form carbonyl chloride (phosgene), a highly poisonous
and corrosive gas.
REFRIGERANT UNDER PRESSURE
is used in the operation of this equipment.
or severe injury may result if you fail to observe safety precautions.
Never use a heating torch on any part that contains refrigerant 22. Do
not let liquid refrigerant touch you, and do not inhale refrigerant gas.
DETECTING AND REMOVING MOISTURE.
a. Detecting Moisture. Excessive water vapor may enter the refrigeration system, At the
low temperatures developed in the system, this vapor condenses and may freeze the expansion
valve in an open or closed position. The operating characteristics of a unit with a frozen
expansion valve are given below.
(1) Valve Frozen Shut. If expansion valve is frozen shut, the following operating
characteristics may be observed:
(a) Unit operates continuously; box temperature remains high.
(b) Suction pressure remains abnormally low.
(c) Suction tubing remains abnormally warm.