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The water regulating valve must close off condenser water flow completely during the “hot gas” harvest cycle.
There should be no discharge water flowing out of the condenser during the harvest cycle. Should the valve fail
to close during the harvest mode, the condenser will continue to condense the compressor discharge vapor
needed for the harvest cycle and this will result in long harvest times.
Leaking (bypassing) water regulating valves are normally the result of scale build-up on the valve diaphragm
and the valve should be flushed, not replaced. To flush the valve, open the adjusting stem wide open CCW (or
force the valve spring up with a screwdriver), open and close the water supply to the condenser resulting in the
flushing action. Should this not correct the problem, replace the valve diaphragm. This can be done without en-
tering the sealed refrigeration system.
Damage to the water regulating valve may also be caused by water hammer. Water hammer will result from the
condenser inlet and outlet water lines being reversed or defective valve stops in the water supply line. Proper
installation of water--cooled equipment should always include an anti-water hammer standpipe in the supply inlet
line as close to the cuber as possible.
SERVICE STEM VALVES
When closing the service stem valves to remove your gauge and manifold set always close the high side stem
valve first. Following this procedure will allow the system to “PULL” the refrigerant vapor from your manifold set
to reduce refrigerant loss. When the pressure has been reduced, close the low side stem valve.
MOISTURE CONTAMINATION
With the major changes in refrigerants in today’s marketplace and the use of hydroscopic oils the control of
moisture and contaminates have become more critical to safeguard against than ever before in the history of
mechanical refrigeration.
Contaminates are also the most difficult of all problems to determine. A Meg-Ohm meter “Megger” can be a
valuable tool to aid in the analysis of this problem. A Meg-Ohm reading log may be started any time after 90
days of operation of the product. To perform the test, proceed as listed.
Disconnect all three (3) compressor leads, take a Meg-Ohm meter reading from each compressor terminal to a
good chassis ground. Compare reading to chart below:
Meter Reading
Meg-Ohm
Compressor Condition Maintenance Required
100 - ¥
Okay None needed.
50 to 100 Moisture present Replace drier.
20 to 50 Severe moisture & possible con-
taminated oil with acid present
Replace drier with acid hold type.
Run 24 hours, change to regular
drier.
.5 to 20 System has severe contamination Remove compressor oil and refrig-
erant charge. Evacuate, install liq-
uid and suction line driers (acid
hold type). Recharge with new oil
and refrigerant. Run 24 hours. Dis-
charge system, discard suction
line drier, replace the liquid line dri-
er. Evacuate and recharge.
