Toshiba HFC R407C Service Manual page 73

Additional refrigerant charging method
(1) Loosely connect the refrigerant cylinder hose to the gauge manifold, then open the source valve V
the cylinder, purge the air in the hose, and then tighten the hose.
(2) As shown in the diagram below, turn the refrigerant cylinder upside down, open the valve V
gauge manifold, and then charge the liquid side pipe with refrigerant in the liquid state. (Note that with
some types of refrigerant cylinders, the liquid refrigerant will be output through siphoning action with
the cylinder in the normal upright position.) If the proper charging amount cannot be reached, close
the valve V , turn the refrigerant cylinder upright, open the liquid-side and balance packed valves
H
completely, and open the gas-side packed valve only half way. Begin the cooling operation, open
valve V , and then charge the gas-side pipe with refrigerant in the liquid state.
L
(3) While watching the scales display, quickly close the valve V
charged with the proper amount of additional refrigerant. Then close the source valve V
cylinder, and open the gas-side packed valve completely.
(4) Record the amount of additional refrigerant that was added to the system on the nameplate inside the
front panel (lower) of the outdoor unit.
4.5 5.5 7.0
Indoor unit
Refrigerant pipe installation
Liquid pipe
Gauge manifold
Gas pipe
Refrigerant
Gas
bottle
Liquid
V
a
Scales
completely when the system has been
L
Packed valve
(liquid side)
Low High
pressure
pressure
V
H
V
L
Packed valve (discharge gas side)
Refrigerant
Outdoor unit
gas
on
H
on the
H
on the
a
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