Basic Function Of The Service Valves; Pump Down - Sanyo KHS0951 Installation Instructions Manual

Basic Function of the Service Valves

The basic function of the service valves are given in Table 7 below.
Table 7
Action
Shipping
Operating and
test running
the air conditioner
Measuring pressure
and gas charging
Air purging with
a vacuum pump
* 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. 55)

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.
(2) Using a hex wrench, turn the narrow tube service
Narrow Tube Service
Valve (2-Way)
CLOSED
Fully OPEN
Fully OPEN
CLOSED
Wide Tube Service
Valve (3-Way)
O-ring Valve cap
Stem
*
*
Hose with push-pin
PUSH
Fig. 55
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 opera-
tion.
(4) When the low pressure gauge reading falls to 1 to
0.5 kg/cm 2 (14.2 to 7.1 PSI), fully close the wide
tube valve stem with a standard screwdriver. Then
quickly stop the unit.
(5) Disconnect all gauges and hoses, and replace the
bonnets and the valve caps as they were before.
21
Service valve