Specifications

33
Tightening Connection
● Align the center of the pipes.
● Sufficiently tighten the flare nut with fingers, and then tighten it with a spanner and
torque wrench as shown.
CAUTION:
● Excessive torque can break nut depending on installation conditions.
Hex nut diam. (mm) Tightening torque (N.m)
Φ 615~20
Φ 9,52 31 ~ 35
Φ 12 50 ~ 55
Φ 16 60 ~ 65
Air purging
Air and moisture in the refrigerant system have undesirable effects as indicated below
:
● Pressure in the system rises.
● Operating current rises.
● Cooling or heating efficiency drops.
● Moisture in the refrigerant circuit may freeze and block capillary tubing.
● Water may lead to corrosion of parts in the refrigeration system.
Therefore, the indoor unit and tubing between the indoor and outdoor unit must be
leak tested and evacuated to remove any non condensable and moisture from the
system.
Air purging with vacuum pump
● Preparation
Check that each tube (both liquid and gas side tubes) between the indoor and
outdoor units have been properly connected and all wiring for the test run has been
completed. Remove the service valve caps from both the gas and the liquid side on
the outdoor unit.
Note that both the liquid and the gas side service valves on the outdoor unit are kept
closed at this stage.
● Pipe length and refrigerant amount:
● When relocate the unit to another place, perform evacuation using vacuum pump.
Make sure the refrigerant added into the air conditioner is liquid form in any case.
Caution in handling the packed valve
● Open the valve stem until it hits against the stopper. Do not try to open it further.
● Securely tighten the valve stem cap with a spanner or the like.
● Valve stem cap tightening torque (See Tightening torque table in previous page).
When Using the Vacuum Pump
(For method of using a manifold valve, refer to its operation manual.)
1. Completely tighten the flare nuts, A, B, C, D, connect the manifold valve charge
hose to a charge port of the low-pressure valve on the gas pipe side.
2. Connect the charge hose connection to the vacuum pump.
3. Fully open the handle Lo of the manifold valve.
Indoor unit
Outdoor unit
Manifold gauge
Pressure
gauge
Charge hose
Nitrogen gas cylinde
r
(in vertical position)
Indoor unit
Outdoor unit
Pressure
gauge
Manifold gauge
Open
Close
Vacuum pump