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03TA Service Manual
SYMPTOM: High head pressure. (Water-cooled machine)
POSSIBLE CAUSE
Misadjusted or defective water regulating
valve
Insufficient water supply.
Cooling tower needs maintenance.
Non-condensables (usually air) in system.
Fouled (dirty) condenser.
2/14/07
POSSIBLE REMEDY
Adjust or replace the valve. Never adjust the
valve stem as far open as it will turn, because
it will not close when the head pressure drops.
Check size of water line and pump output at
the condenser. Refer to the specification sheet
for water requirements. Check cooling tower
sump level and make-up water supply.
Check cooling tower fan belt and tighten or
replace as needed. Check spray nozzles and
sump screen and clean as needed.
Check
refrigerant
pressure/temperature
condensables are present, Perform a total
pumpdown, let stand for at least 6 hours,
allowing non-condensables to gather in the
upper part of the receiver.
freezer and attach a recovery unit to the top
receiver purge valve (59). Open the valve and
recover the vapor for about five minutes.
When the freezer is evacuated, open the thaw
gas solenoid valve manually for about 15
seconds letting the top vapor in the receiver
blow into the freezer.
valve and evacuate the freezer again.
Evacuate to 500 microns and restart the
machine.
Follow the diagnostic procedure outlined on
page 7-3, Section 7, and clean the condenser
per instructions under Condenser Cleaning,
TROUBLESHOOTING
tables
for
correct
relation.
If
non-
Evacuate the
Close the solenoid
8-9
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