Vogt P18AL TUBE-ICE, Service Manual

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P18AL Service Manual
STAR-UP AND OPERATION
3/6/07
5-4
Transferring refrigerant from a refrigeration system into a cylinder can be very dangerous
and is not recommended.
As the machine is being charged, continually observe the following operating characteristics:
a)
Discharge pressure - 175 psi to 200 psi maximum
b) Compressor oil pressure - Mycom W-Series,18-27 psi, Vilter 450-Series, 35-50 psi.
Other models will vary (check manufacturer’s specifications).
c) Liquid level in receiver
d) Compressor oil level
While charging the machine, the low pressure switch will stop operation of the compressor at set
point pressure. The switch will automatically reset at the differential pressure at which time you can
restart the machine (some low pressure switches may be manual reset). It is best to use warm water
in the tank and open the tank drain valve somewhat to allow cold water to exit and warm water to
enter continually. The idea is to prevent ice from freezing in the tubes as much as possible while
charging. It may be necessary to initiate a short harvest cycle to dispel any ice made.
To initiate a harvest cycle, close the charging valve and push the start/manual harvest push button
(PB2) while the compressor is running. This will initiate a harvest and another freeze cycle will
start immediately following to continue the charging procedure. Be sure to close the cylinder shut
off valve during the harvest period and open it once the machine goes back into the freeze cycle.
When the liquid level in the receiver is near the pump down level and the freezer is down to 15 psi
suction with little of no frost on the shell, you can stop the charging procedure and disconnect the
cylinder. Make sure the charging valve is closed and the cylinder valve is closed before attempting
to disconnect the cylinder. Loosen the union in the charging line gradually to relieve the ammonia
pressure slowly.
When charging is complete, stop the machine, disconnect and lock-out the power. If the machine
contains a pressure switch, open the control panel door and reconnect. Open liquid line stop valve
(24) and/or receiver liquid feed valve and you will hear liquid refrigerant flowing through to the
liquid solenoid valve (25). Turn main power disconnect to the on position and the machine is ready
for start-up and ice production.