Vogt TUBE-ICE P-118F, Service Manual

Page: 72 / 115

P118F Service Manual
SERVICE OPERATIONS
1/6/09
9-2
Float Switch. The float switch is installed on a header assembly that is attached to the freezer shell.
Valves are provided for isolation of the float switch assembly if replacement or servicing is
necessary. The float switch closes as the level of refrigerant in the freezer rises and opens as the
level falls.
The float switch is connected to the “A1” solenoid valve coil. This is the solenoid valve directly
before the hand expansion valve. Therefore when the refrigerant level in the freezer drops, the float
switch closes, thereby energizing and opening the “A1” liquid feed solenoid until sufficient level has
been reached to open the float switch. The float switch has a fixed 1/2” differential.
The float switch is installed at the correct height at the factory and should not need to be adjusted.
The float switch is installed at the position which provides highest capacity. The correct height will
produce compressor superheat which climbs throughout the freeze cycle to a minimum of 30° F.
Hand Expansion Valve. The hand expansion valve is located directly after the “A1” solenoid
valve. This valve should be set at a point where the float switch is open for a length of time
approximately equal to the time it is closed.
Capillary Bypass. The capillary bypass is located directly following the “A2” solenoid. The “A2”
solenoid should be energized (Open) during the entire freeze cycle. The function of the capillary
bypass is to meter a set minimum amount of refrigerant to the freezer during the freeze cycle,
thereby reducing cycling of the float switch.