A/C System Flushing Procedure - New Holland T8010 Manual

When flushing is necessary, all effected components
should be flushed to eliminate the possibility of
contaminants remaining in the system.
There are two methods of A/C system flushing:
individual component flushing and complete
circuit flushing. The complete circuit is the system
minus the compressor, receiver-drier and thermal
expansion valve. The compressor, receiver-drier and
ther mal expansion valve are always bypassed
(removed) during circuit flushing and ser viced
individually. The receiver-drier is always replaced
anytime a system is flushed. The expansion valve,
due to its small orifices, is removed from the system
and cleaned (or replaced). The compressor is either
replaced or reused, but is NEVER flushed.
The preferred method of system flushing is individual
component flushing. Given the size of New Holland
equipment and the distance between components,
individual component flushing will dislodge and flush
out more contamination than complete circuit
flushing. Which individual components are flushed
will depend on the source of the contamination and is
left to the discretion of the technician.
For "mildly" contaminated systems, complete circuit
flushing may be used, where the contamination is
oxidized refrigerant oil or small amounts of receiver-
drier desiccant. Complete circuit flushing requires
little system disassembly, minimal special connectors
and the least amount of service time.
The most likely sources of contamination are
compressor failure and receiver-drier failure.
Compressor Failure
A fa i l ed c o m p r e s s o r g e n er a l l y s e nd s d e b r i s
downstream to the condenser, the receiver-drier and
t owa r d s t h e t he r m a l ex p a n s i on va l ve. I f t h e
compressor fails internally, it must be replaced. Also
i n d i v i d u a l f l u s h i n g o f t h e h o s e b e t we e n th e
compressor and condenser, of the hose between the
condenser and receiver-drier, of the condenser itself
and replacing the receiver-drier are appropriate
service actions for compressor failure.
For most New Holland condensers with a single flow
path, flushing effectively removes debris. For
condensers with parallel flow paths, since flushing
takes the path of least resistance around any
blockage, condenser replacement may be the only
option.
Section 50 - Climate Control - Chapter 2

A/C SYSTEM FLUSHING PROCEDURE

The receiver-drier has a fine mesh screen to capture
contaminants, but the contaminants may penetrated
the screen. Check the discharge port of the receiver-
drier to see if contaminants have penetrated the
screen. If so, individual flushing of the hose between
the receiver-drier and the expansion valve and
c l e a n i n g t h e t h e r m a l ex p a n s i o n v a l v e a r e
appropriate. If the ther mal expansion valve is
damaged, replace it as well.
Additional flushing of the system beyond the thermal
expansion valve is at the discretion of the service
t e c h n i c i a n w h o c a n b e s t j u d g e h o w fa r t h e
contamination has traveled.
Receiver-Drier Failure
Receiver-driers should not normally fail if replaced:
A. when system has been opened before.
B. when receiver-drier has been in service two or
more years.
C. when the system has been open for a long
period of time because of a leak (broken
hoses, loose connection) that has permitted air
and moisture to enter the system.
D. when contaminated refrigerant was recovered
from the system.
However, if the desiccant pouch is punctured by a
debris from a failed compressor or fails from age,
desiccant particles may flow downstream toward the
thermal expansion valve and the evaporator. An
indicator of receiver-drier failure is soft golden-brown
particles found at its outlet. The thermal expansion
valve should always be checked after receiver-drier
failure.
If the receiver-drier fails, it must be replaced. Also
individual flushing of the liquid hose between the
receiver-drier and the thermal expansion valve and
cleaning the valve are appropriate.
Che ck the s uc tio n li ne fr om the val ve to th e
compressor and the compressor suction por t. If
golden brown particles is found, flush the evaporator
and suction line individually. The compressor may be
reused AFTER all contaminants are removed:
1. Use the dipstick to measure the compressor oil
level.
2. Drain and refill the compressor with PAG oil until
the drained oil is free of particles.
50-2-34