Monaco SIGNATURE 2001 series, Руководство пользователя

Страница: 249 / 327

Chemical Stability:
The air conditioning system life and efficient operations depends upon the
chemical stability of the refrigeration system. The refrigeration system uses
the refrigerant R134a and Polyakylene Glycol (PAG) a synthetic lubricant. It
is very important that all materials contained within the refrigerant system be
chemically compatible. The only suitable compound for use with R134a is
PAG. The amount of PAG within the refrigerant system is approximately 18%
of the total refrigerant in the system.
How much refrigerant is in the system or how much should be used when
charging?
The system uses 1 oz. of PAG oil for each 7 feet of hose after the first ini-
tial 15 feet. Roughly, a 40 foot motorhome will use a total of 92 feet of
refrigerant hose. Subtracting the initial 15 feet from the total measurement
the net amount amount of hose is 77 feet. Divide 77 feet of hose by 7 to
obtain the total which equals 11 ozs of PAG oil required. Carrying the formu-
la one step further, the 11oz. equal approximately 18% of the entire system.
The total amount of refrigerant in the system is approximately 61 oz. or 3.8
lbs. of R-134a.
High pressure readings are another way to determine the amount of cor-
rect amount of refrigerant charge. Ambient temperature effects the high pres-
sure readings. The ambient temperature is measured one inch away from the
condenser. Record the temperature reading then add 40º F. Use the tempera-
ture/pressure chart to adjust the amount of refrigerant being introduced into
the system.
PSIG:
On a fully charged system the expected pressure that should be seen on the
HIGH-SIDE gauge will be around 200 PSIG.
NOTE: All systems are charged at the factory with 4.0 lbs of R134A.
R-134a Refrigerant:
R134a is classified non-explosive, non-flammable and non-corrosive. There
is hardly any odor and it is much heavier than air. R134a is ozone friendly;
however, it is not technician friendly. Proper care in handling and adequate
ventilation must be observed. Under normal atmospheric pressures and tem-
peratures R134a will evaporate so quickly it will freeze anything it comes in
contact with. The open container boiling point for R134a is minus 21.7º F.
This low boiling point makes for an ideal refrigerant. The tremendous
amount heat transfer which occurs when a liquid boils, or vapors condense,
forms the basic principles of all A/C systems. The BTU is the standard meas-
urement of an air conditioner system. The amount of heat required to raise or
lower the temperature of one pound of water by 1º F equals one British
Thermal Unit (BTU).
Electrical Systems - Chassis
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
S I G N A T U R E
9 • 2 4 9
About Refrigerants