I Basic Functions Of The Service Valves; I Pump Down - Technibel MCAF188R5I Installation Instructions Manual

06-154 MCAF186 - 246R5I ENG
I
Basic Functions of the Service Valves
The basic functions of the service valves are given in Table 8 below.
Table 8
Action
Shipping
Operating and
test running
the air conditioner
Measuring pressure
and gas charging
Air purging with
a vacuum pump
CAUTION
When opening or clos-
ing the service valve
stem, use the hex
wrench. Be sure to fully
seat the wrench before
turning the valve.
I
Pump Down
Pump down means collecting all refrigerant gas in the
system back into the outdoor unit without losing any of
the gas. Pump down is used when the unit is to be
moved or before servicing the refrigerant circuit.
Pump Down Procedure
Be sure to carry out pump down with the unit in
cooling mode.
(1) Connect the Lo side charging hose of the manifold
valve to the service port on the wide tube service
valve.
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Narrow Tube Service
Valve (2-Way)
CLOSED
Fully OPEN
Fully OPEN
CLOSED
Close
Open
Hex
wrench
Fig. 60b
Wide Tube Service
Valve (3-Way)
O-ring Valve cap
Stem
*
*
Hose with push-pin
PUSH
Fig. 60a
(2) Using a hex wrench, turn the narrow tube service
valve clockwise all the way to close the service
valve. (Be sure to confirm that the wide tube ser-
vice valve is fully open.)
(3) Press the operation button and start cooling
operation.
(4) When the low pressure gauge reading falls to 1 to
0.5 kg/cm 2 , fully close the wide tube valve stem.
Then quickly stop the unit.
(5) Disconnect all gauges and hoses, and replace the
valve caps as they were before.
22
* The service port on the wide
tube service valve uses a
Schrader core valve to access
the refrigerant system. Therefore,
be sure to use a hose connector
which has a push-pin inside.
(Fig. 60a)
Service valve