New Holland CX720 Repair Manual page 3073

BODY AND STRUCTURE - ENVIRONMENT CONTROL Air-conditioning system
ENVIRONMENT CONTROL Air-conditioning system - Check (E.40.C
- F.45.A.10)
1. At times you may question whether or not a con-
tainer of refrigerant has been recycled. One method
is a simple comparison of the container pressure with
theoretical pressure at a known temperature. If the
pressure is equal to or less than a theoretical value
established for R-134a of usable purity, the contents
of the container does not contain excess air.
IMPORTANT: Using R-134a with excess air will result in
higher system operating pressures and may cause dam-
age to the A/C system.
2. This check can be done in the following manner:
Store the container for at least 12 hours at a known
temperature of 18.3 ° C (65 ° F), or higher. The con-
tainer must not be in direct sunlight or under the in-
fluence of any other direct source of heat.
Carry out all the next steps in the same area in which
the container has been stored, as it is very important
that the temperature of the container is stable.
Attach an appropriate pressure gauge to the con-
3.
tainer. This pressure gauge should read in incre-
ments of 6.9 kpa (1 PSI ).
4. Use a calibrated thermometer to measure the air
temperature within 100 mm (4 in) of the container
surface.
5. Use this table for R-134a to compare the pressure in
the container with the pressure shown for the tem-
perature of the tank. If the pressure in the container
is equal to or less than the pressure in the table, the
refrigerant in the container meets the requirements
for excess air.
6. If the pressure is greater than shown in the table, you
may still be able to use it by proceeding to step 7.
2 4/7/2006
E.40.C / 45
1
1z0o2004112097