Wine Guardian Ducted Split Wine Cellar Cooling Systems (WGS175) - Manual - Manual (Page 40)

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Determining the amount of charge – When “refrigerant side” head pressure control is
utilized on a system, one of the most important factors is determining the total system
refrigerant charge. While on most packaged units the amount of charge is listed on the unit,
the required charge for a field built-up system cannot be listed by the manufacturer. Charge is
usually added when the system is started up until “proper” system performance is reached.
However, this is not satisfactory and if the system is to function properly year-round, the
correct amount of extra charge must be calculated ahead of time.
Procedures for Charging System with Head Pressure Control
WGS40, WGS75, WGS100,WGS175)
NOTE: When charging any system with head pressure control the outdoor
ambient temperature must be known.
Charging of Systems with Head Pressure Control in ambient above 20 degrees C (After
normal evacuation procedures):
1. Connect refrigerant cylinder to a charging or gauge port on the receiver outlet valve.
2. Open the receiver valve approximately one-half way (so receiver and liquid line are
connected to charging or gauge port).
3. Charge liquid refrigerant into the high side of the system. Weighing the charge is
recommended.
4. Remove the refrigerant drum and connect it to the suction side of the compressor.
5. Charge refrigerant vapor into the low side. Do not allow liquid refrigerant into the low
side.
6. Start the system.
7. Observe sight glass (at receiver outlet) to see if system is filling with refrigerant for
normal refrigeration cycle.
CAUTION
BUBBLES IN THE SIGHT GLASS CAN BE CAUSED BY FLASHING DUE TO PRESSURE DROP
FROM PIPE OR ACCESSORY LOSSES, ETC.
If the Sight glass shows bubbles, more refrigerant may be required, while allowing sufficient
time for the refrigerant to stabilize and clear the Sight glass. Use supplied information on the
following pages for proper final charge.