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Flake Ice Machines Refrigeration System
Page F13
Method of Charging Refrigerant
In order to achieve a properly charged refrigeration system, the system must be completely
evacuated.
To achieve a complete evacuation you will need a service gauge manifold with properly
maintained hoses, and a vacuum pump capable of pulling a 50-micron vacuum. This will
require a two-stage pump.
Connect the service gauge manifold to the high and low side service ports and vacuum
pump. Make sure the valves on the gauge manifold are closed, then start the pump.
Note: Do not use a refrigeration compressor as a vacuum pump. Compressors are able
to pull only a 50,000-micron vacuum.
After the vacuum pump has been started, open the valves on the gauge manifold. This will
allow the refrigeration system to start being evacuated.
If there has not been an excessive amount of moisture in the system, allow the vacuum pump
to pull the system down to about 200 microns or 29.9 inches or less. Once this has been
achieved, allow the vacuum pump to operate for another 30 minutes. Then close the valves
on the gauge manifold and stop the vacuum pump. Then watch your gauges. A rise to 500
microns in three (3) minutes or less indicates a dry system under a good vacuum.
If your gauge registers a more rapid rise, the system either has moisture remaining or there is
a leak in the system, requiring a check for the leak, and repair and another complete
evacuation.
Note: Seal the ends of the gauge manifold hose and pull them into a deep vacuum to
determine if the leak is not in the hoses. The gauge manifold should be able to hold the
vacuum for three (3) minutes.
If the refrigeration system is extremely wet, use radiant heat to raise the temperature of the
system. This action will cause the moisture to vaporize at less of a vacuum.
The use of two (2) valves, one between the vacuum pump and gauge manifold and the other
between the refrigerant cylinder and the gauge manifold allows you to evacuate and charge
the system without disconnecting any hoses. If the hoses were disconnected, air or moisture
will have the opportunity to enter the hoses and then the system.
A properly charged icemaker is a service technician’s greatest ally. Proper charging will
allow any concern with the icemaker to be accurately diagnosed.
The refrigerant charge must be weighed into the icemaker either by using a charging scale or
with a dial-a-charge.
The amount of proper refrigerant required for the icemaker is printed on the serial data plate
attached to the icemaker and is listed on the following pages. Never vary the amounts from
those listed.