Sea Frost DC 5000 - Manual (Page 34)

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b) If the pressure readings are over 50 psi with the compressor off, proceed to
check charge level via sight glass and charge if needed. Charge loss indicates a leak
that must be corrected.
STEP 2. If the system continues to operate improperly after Step 1, check for moisture
or dirt plugging the valve. Run the system, observing closely the gauge readings and
plate temperature, noting the following.
a) If system is warm upon start-up, a DIRT-PLUGGED Valve will show an
immediate deep vacuum reading on suction side. Consult SEA FROST for cleaning
techniques.
b) A MOISTURE-PLUGGED VALVE is indicated by a deep vacuum reading on the
suction side after 1 to 5 minutes of operation from warm, followed by any combination of
these symptoms:
c) The temperature at the compressor discharge fitting and the copper tube at the
top of the condenser drops from hot to warm.
d) The temperature of the suction line from the V/U increases.
e) Moisture enters either through suction side leaks or during initial installation and
will freeze at the V/U, reducing or eliminating refrigeration activity. Turning off the
system and allowing the V/U to warm to above freezing, and then restarting, may
temporarily solve the problem. If not, change the RFD as follows.
STEP 3. To change a saturated RFD, allow the system to warm to ambient
temperature, thereby preventing moisture from condensing in the system. A light bulb
in the icebox will speed the warming of the plate. WARNING: BEFORE
DISASSEMBLY OF ANY PART IN THIS SYSTEM BE SURE THE REFRIGERANT IS
COMPLETELY DISCHARGED. With a backup wrench holding the brass body of the
Swagelok fittings on the RFD, loosen and back off the nuts. The tubing may be pulled
out of the fittings. Remove the RFD and replace only with an identical unit by size and
color. The SEA FROST RFD is a drier and also a receiver/filter. The DESICCANT and
the oil in the Sea Frost RFD are special to this system and R-134a. Installation of
the wrong part or oil may destroy the system.
NOTE: This system contains a measured amount of lubricating oil. Be sure the RFD
being installed is a blue SEA FROST Model 24 1/4" x 1/4" RFD.
Follow the "remake" instructions for Swagelok fittings.
Reminder: To ensure removal of system moisture use a high vacuum pump, and
evacuate the system with the highest possible ambient and plate temperatures. A light
bulb or heat lamp in contact with plate is a good warming technique.