Service manual

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5. Suction Line
The suction line is the tube which carries the superheated
vapor refrigerant from the evaporator to the compressor.
6. Compressor
The compressor is called a hermetic compressor which means
that it is completely sealed (welded together). It is, therefore,
not internally field serviceable. Inside the compressor
housing are basically:
a) an electric motor which drives the compressor,
b) a pump which is designed to pump superheated
vapor only,
c) a supply of special refrigeration oil. A small portion
of the oil will circulate out through the system with
the refrigerant, but will constantly return to the
compressor with the refrigerant, so the compressor
will not run out of oil.
7. Discharge Line
The discharge line carries the refrigerant out of the
compressor and to the condenser coil. Remember that as the
refrigerant entered the compressor, it was superheated vapor.
The refrigerant enters the compressor, where more heat is
added and is compressed into a smaller space. The
refrigerant, therefore, leaves the compressor highly
superheated – so if the discharge line is hot to the touch
(burns), don’t be surprised – it should be.
8. Condenser Coil
The purpose of the finned condenser coil is to transfer heat
from the high pressure refrigerant to the warm outdoor air.
As the outdoor air passes over the coil, the heat transfer will
cause the air temperature to rise. Thus the condenser
discharge air will be several degrees warmer than the
condenser entering air.
As the refrigerant passes through the first few tubes of the
condenser, its temperature will be lowered or it will be de-
superheated. After the refrigerant is de-superheated, it will
begin to condense or change from a vapor to a liquid and will
remain at a nearly constant temperature throughout almost all
of the remainder of the coil. This temperature is called the
condensing temperature or high side saturation temperature
and will always be higher than the condenser entering air
temperature.
Near the bottom of the condenser, the refrigerant will all be
condensed to a liquid and from there on its temperature will
drop to more nearly the temperature of the outdoor air. After
the temperature of the refrigerant drops below condensing or
saturation temperature, we call its condition sub-cooled
liquid.
During all of the three processes in the condenser (de-
superheating, condensing, sub-cooling), the refrigerant gives
up heat; but most of the heat is given up during the
condensing process.
II. AIR HANDLING CIRCUITS
1. Motors and Fans
One motor turns both the condenser fan blade and evaporator
air blower. The condenser (outdoor) fan is an axial flow
(propeller) type and the evaporator (indoor) fan or blower is a
centrifugal (squirrel cage) type.
2. Filters
The filters should always be in place when the system is
running. More important than their purpose of cleaning the
air in the living space is the protection the filters give the
evaporator coil. Without filters, a wet evaporator coil will
quickly stop up so that adequate air cannot pass through it.
Filters must be installed to completely fill the filter rack so
that no air can flow around them or by-pass them and carry
dust, lint, etc. to the evaporator. To clean an evaporator that
has not been properly protected by its filter, the entire unit
must be removed from the recreational vehicle and the coil
cleaned with special detergent and water.
III. ELECTRIC POWER CIRCUITS
1. Safety
Voltage (electrical pressure), whether high or low, will not
hurt you. It is the current through vital parts of your body
that does the damage, and under the right conditions, 115
volts (domestic USA) is plenty to drive a deadly dose of
current (amperes) through your body.
Another imminent danger from electric shocks in addition to
electrocution is reaction. An electrical shock causes
uncontrollable muscular contractions which can cause further
injuries.
Remember that electricity can be very dangerous, but you can
safely work with it. In order to be safe, you must know what
you are doing. You must work deliberately and carefully.
You must think safety before each move.
THINK SAFETY
2. Power Supply - from Commercial Utility
1) Wire Size