Vogt P118F/HE100, Service Manual

Page: 95 / 126

05TA Service Manual
SERVICE OPERATIONS
7/24/13
9-17
Condenser Cleaning.
See “Water Cooled Condensers”, “Maintenance”, Section 7.
Air-Cooled Condenser.
Visual inspection will indicate if dirt is accumulating and clogging the fin
face of the condenser. A vacuum cleaner, compressor air or a brush may be used to remove any
accumulation of dirt from the fin section of the condenser.
Pumpdown.
The function of the pumpdown is to transfer all of the liquid refrigerant from the
freezer (evaporator) into the receiver. Pump-down should only be performed when the freezer is
clear of ice. Its main purposes are:
1. Before Cleaning machine
2. To check the total refrigerant charge.
3. To perform service or repair work on the machine.
4. To winterize the machine.
5. To prepare the machine for disconnecting and moving.
To perform a pumpdown, follow this procedure:
1. Push manual harvest button to clear the freezer of all ice and stop operation.
2. Close the liquid stop valve (58) at the receiver.
3. Open the water tank drain valve (39) partially to allow a continuous flow
of warm make-up water into the water tank, and still maintain a good
level in the tank. An auxiliary supply of warm water (not to exceed 100
° F)
may be used if available. Warmer water affords a more complete pumpdown.
4. Start the machine and allow it to operate and complete one harvest
5. During the thaw cycle, close the 1/4" valve (69) at the top of the freezer to
isolate the freezer pressure switch and prevent another thaw cycle.
6. Allow the machine to operate until the low pressure switch stops the machine
@ 20 PSIG. If a lower pressure is desired, it can be accomplished by lowering the
low pressure switch and starting and stopping the machine by the "Start" and "Stop"
push buttons. Continually observe the oil level to make sure the oil is not carried
from the compressor while operating at a low pressure.
7. Close the thawing gas stop valve (90), the receiver liquid return stop valve (91),
the compressor suction valve (34), the compressor discharge valve and the oil
return stop valve (70).