Caution At Replacement Of Expansion Valve - Hitachi RCUE40AG2 Service Manual

Maintenance

With economizer:

Without economizer:

CAUTION
There will be a clearance
between control value
and actual value of
expansion valve opening,
therefore, zero point
adjustment (re-input of
power source) should be
realized.
Operate chiller unit
pag. 175

6.11.5. Caution at Replacement of Expansion Valve

The replacement of expansion valve can be performed by collecting the
refrigerant to air side heat exchanger in the method shown in the "1 Collection of
Refrigerant". And pay attention to the following points.
Electrical expansion valve is used in this product, and its opening is almost
closed (10 pulse) at compressor stop. Therefore, when removing the welding of
expansion valve, it is important not to remain the refrigerant between liquid outlet
valve of air side heat exchange (A) and expansion valve.
1. In case of the model with economiser
Liquid outlet valve of air side
heat exchanger (A)
Close
This fl are should be removed
before heating (*) part
2. In case of the model without economiser
Liquid outlet valve of air side
heat exchanger (A)
Close
This operation makes expansion valve open in spite of compressor stop by low pressure
setting.
Compressor is started up
and when starting unload is
fi nished
SMGB0003 rev.0 - 11/2006
Ex. valve
10 pulse (close)
The coil should be removed
while refrigerant is being
collected collected
Ex. Valve
Remove the coil of ex. valve
To compressor
From air side
heat exchanger heat exchanger
Economiser Economiser
Applicable model:
Close outlet valve of air side
heat exchanger
6 6