Vogt HEC-10, Service Manual

Page: 91 / 114

HEC-Series Service Manual
SERVICE OPERATIONS
10/21/01
9-9
Control Circuit Protection. The electrical control circuit of the machine is protected by two 2.5
amp fuses (FU100 & FU200). If either of these fuses should blow, the machine will immediately
stop. Before replacing a fuse, open the disconnect switch to machine and set the “Ice” push button to
the “Off” position. If the machine was off for an extended time, the crankcase heater must be
energized for a minimum of two hours before restarting the machine. Make sure there is no liquid
refrigerant in the compressor crankcase before attempting to restart the machine. When ready to
restart the machine, depress the “Ice” button, then the “Start” button. Allow the machine to operate
for approximately two minutes and then depress the “Manual Harvest” button to clear the freezer of
any ice. The machine will automatically return to a freeze cycle upon completion of the harvest cycle.
Circulating Water Pump Motor. The motor bearings are pre-lubricated and sealed. They require
no further lubrication. Pump should operate with the water level above the impeller housing.
The pump is equipped with a mechanical seal which is self-addressing and requires no lubrication.
However, the pump should not be operated unless circulating water. The pump manufacturer
recommends that a mechanical seal be kept as a spare. When ordering a seal, specify pump size, type,
serial number, and manufacturer’s name as indicated on the nameplate.
Condenser Cleaning. See Maintenance, Section 7, “Water Cooled Condensers”.
WC Condenser Service. High head pressure due to fouled condenser.
Eliminate other possible causes:
•
Non-condensables
•
Faulty gauge
•
Refrigerant restriction
•
Water regulating valve
•
High inlet water temperature
•
Insufficient water supply
Example
Liquid return (RCVR) Psig = 200 = 102
°
F (SAT)
Water outlet temperature = 95
°
F
Difference = 7
°
F
If difference is more than 10
°
F, cleaning is indicated. For cleaning procedure see, “Water Cooled
Condenser Cleaning”, Section 7.