■Basic Functions of the Service Valves
The basic functions of the service valves are given in Table 8 below.
Table 8
Action | Narrow Tube Service | Wide Tube Service | ||
Valve | Valve | |||
| ||||
| CLOSED |
| Valve cap | |
|
|
| Stem | |
Shipping
Fully OPEN
Operating and test running
the air conditioner
| Fully OPEN |
|
Measuring pressure | * |
|
and gas charging |
|
|
| CLOSED |
|
| * | The service port on the wide tube ser- |
Air purging with | * | vice valve uses a Schrader core valve |
a vacuum pump |
| to access the refrigerant system. |
|
| Therefore, be sure to use a hose con- |
|
| nector which has a |
|
| (Fig. 60a) |
Service valve
CAUTION | Hose with |
| |
| Close |
When opening or clos-
ing the service valve |
| PUSH |
Open |
| |
stem, use the accessory |
| |
Hex | Fig. 60a | |
hex wrench. Be sure to | wrench |
|
|
| |
fully seat the wrench | Fig. 60b |
|
before turning the valve. |
|
|
■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 valve clockwise all the way to close the service valve. (Be sure to confirm that the wide tube service valve is fully open.)
(3)Press the operation button and start cooling oper- ation.
(4)When the low pressure gauge reading falls to 14.2 to 7.1 psi (1 to 0.5 kg/cm2), 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