Vogt P118F/HE100, Service Manual

Page: 79 / 126

05TA Service Manual
SERVICE OPERATIONS
7/24/13
9-1
Adjustable Blowdown
(petcock valve)
Automatic
Blowdown
Water Pump
9. Service Operations
Adjustable Blowdown (for clearer ice)
A petcock is installed on the overflow of the water pump to
provide means for obtaining blowdown from the water tank during the freezing period. The petcock
was set at the factory to discharge enough water during the freeze cycle to produce clear ice. After
installation it should be adjusted to the minimum rate required to maintain clear ice and checked
after a few days of ice making.
FIGURE 9-1
Water Pump / Blowdown Assembly
Automatic Blowdown (Harvest Cycle).
A feature of this machine is the automatic blowdown (40)
which is provided to eliminate or reduce the necessity for frequent flushing or cleaning of the water
tank (7) and to remove accumulated salts or solids in the water as a result of the freezing action.
During the harvest water returning from the freezer raises the tank level and causes an overflow of
water which creates a siphon to remove a fixed amount of water from the tank.
Float Valve (make-up water).
The make-up float valve (12) maintains the
proper pumping level in the water tank for ice making. The valve should be set to maintain a water
level in the water tank during the freezing period, so that there will be a quantity of by-pass or
blowdown only during the thaw mode. The water level during the freeze mode should always be
below the by-pass piping to prevent excessive waste of cold water, resulting in loss of ice capacity.
If it should become necessary to clean the float valve, close the stop valve in the make-up water line
to the machine and remove the float valve. After the valve has been cleaned and reinstalled, check
to ascertain if the proper water level is being maintained. After the machine is stopped and the water
in the tank seeks its normal level, there should be no water flow through the float valve or drain by-
pass.
It is advisable to install a large area strainer in the water supply line to protect the float valve from
dirt or solids in the water, which would necessitate frequent cleaning.
Part #: 12A4200H0402