Vogt P118F/HE100, Service Manual

Page: 77 / 126

05TA Service Manual
TROUBLESHOOTING
7/19/13
8-9
SYMPTOM: High head pressure. (Water cooled machine)
POSSIBLE CAUSE POSSIBLE REMEDY
Misadjusted or defective water regulating valve 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.
Insufficient water supply. 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.
Cooling tower needs maintenance. Check cooling tower fan belt and tighten or
replace as needed. Check spray nozzles and
sump screen and clean as needed.
Non-condensables (usually air) in system. Check refrigerant tables for correct
pressure/temperature relation. If non-
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. Evacuate the
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. Close the solenoid
valve and evacuate the freezer again.
Evacuate to 500 microns and restart the
machine.
Fouled (dirty) condenser. Follow the diagnostic procedure outlined on
page 7-3, Section 7, and clean the condenser
per instructions under Condenser Cleaning,