Section 9 --- Electrical Systems - Chassis
The Executive 2005
412
How much refrigerant is in the system? How much should be used when charging? You will
need 1 oz. of PAG for each 7 feet of hose after the first 15 feet of hose. Roughly, a 40 foot motorhome
will use 92 feet of refrigerant hose. Take 15 feet off the measurement and the result is 77 feet. This 77
feet is then divided by 7 for total of 11, and represents the number of ounces of PAG oil needed for the
A/C system (11 oz.).
Carrying the formula one step further, the 11 oz. equal approximately 18% of the entire system. The
total will equate to approximately 61 oz. or 3.8 lbs. of R134a.
High pressure readings are another way to determine the amount of charge. The ambient tem-
perature reading is measured one inch away from the condenser. The ambient temperature reading,
plus 40° F, will equate to a value from the pressure table.
EXAMPLE:
90° F. 1 inch from condenser + 40° F = 130° F ----- 198.90 PSIG -
On 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. A fluorescent dye has been added for leak detection.
psi gauge_temp.eps
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