Sanyo 85464359982001 Air Purging with a Vacuum Pump for Test Run Preparation, Leak test

07-007 W-2WAY_II_NA 1/23/07 6:09 PM Page 67

7. AIR PURGING

Air and moisture in the refrigerant system may 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 refrigerant system

Therefore, the indoor unit and tubing between the indoor and outdoor unit must be leak tested and evacuated to remove any noncondensables and moisture from the system.

■Air Purging with a Vacuum Pump (for Test Run) Preparation

Check that each tube (both liquid and gas tubes) between the indoor and outdoor units have been properly connected and all wiring for the test run has been completed. Remove the valve caps from both the gas and liquid service valves on the outdoor unit. Note that both liquid and gas tube service valves on the outdoor unit are kept closed at this stage.

Leak test

(1)With the service valves on the outdoor unit closed, remove the 5/16" flare nut and its bonnet on the gas tube service valve. (Save for reuse.)

(2)Attach a manifold valve (with pressure gauges) and dry nitrogen gas cylinder to this service port with charge hoses.

CAUTION	Use a manifold valve for air purging.
	If it is not available, use a stop valve
	for this purpose. The “Hi” knob of
	the manifold valve must always be
	kept closed.

Pressure gauge

Manifold gauge

Fig. 7-1

Vacuum pump

Outlet

Inlet

Fig. 7-2

Manifold valve

Lo Hi

Charge hose

Cylinder valve

Nitrogen gas cylinder (In vertical standing position)

(3)Pressurize the system to no more than 469 psig (33 kgf/cm2G) with dry nitrogen gas and close the cylinder valve when the gauge reading reaches 469 psig (33 kgf/cm2G). Then, test for leaks with liquid soap.

CAUTION	To avoid nitrogen entering the
	refrigerant system in a liquid state, the
	top of the cylinder must be higher than
	the bottom when you pressurize the
	system. Usually, the cylinder is used in
	a vertical standing position.

Open

Gas tube

Close

Open

Liquid tube

Close

Open

Balance tube

Close

Fig. 7-3

Outdoor unit

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