14. Refrigerant charging
When charging the air-conditioning system with refrigerant, it is important that oil is not
pushed or washed away from the sump of the compressor; otherwise immediate damage to
the compressor internal assembly will occur. To avoid this situation, the position of entry for the
refrigerant to the compressor and system must be considered as follows;
a)
Most bus and coach applications have a system layout with the evaporator on the roof or at
least in a position which is higher than the compressor. The preferred procedure for adding
refrigerant and oil to the system is at this higher point. This will ensure the correct flow of
refrigerant vapour and oil will pass through the compressor without any adverse effects to its
initial operation.
b)
If it is not possible to access the system at the evaporator or roof level, then service points in
suction and discharge lines away from the compressor are the next best option.
c)
If refrigerant must be added at the compressor, and there is no other alternative, only
refrigerant vapour is to be added at the discharge and suction manifold valves at the side and
top of the compressor (see diagram).
d)
Under no circumstances is refrigerant to be added at the R134a coupling service valves ( if
fitted) on the rear cap of the compressor. These valves are used for diagnosis only.
If any further assistance or information is required please go to www.unicla.hk
or contact your nearest Unicla dealer.
Charging at the compressor.
Add vapour refrigerant only at
manifolds (suction and discharge)
Do not add refrigerant at R134A
coupling service valves (if fitted)
Use for diagnosis only
Recommended points
for charging the system
(adding the refrigerant)
Unit
UWX
9.
Summary of Contents for UWX440
Page 1: ...UWX550 and UWX440 Installation Guidelines...
Page 13: ...Notes...
