Sanyo XMHX1252, XMHX1852 Air Purging with a Vacuum Pump for Test Run Preparation, Leak test

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 evacu- ated to remove any noncondensables and moisture from the system.

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

Check that each tube 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 all service ports on the outdoor unit. (Fig.

7-2) Note that all service valves on the outdoor unit are kept closed at this stage.

The balance tube leak test is not necessary if only 1 outdoor unit is installed.

Leak test

(1)Attach a manifold valve (with pressure gauges) and dry nitrogen gas cylinder to all service ports with charge hoses.

The balance tube leak test is not necessary if only 1

outdoor unit is installed.

Use a manifold valve for air CAUTION purging. If it is not available, use a stop valve for this pur-

pose. The “Hi” knob of the manifold valve must always be kept closed.

(2)Pressurize the system to no more than 469 psig

(33 kgf/cm2G) with dry nitrogen gas and close the cyl- inder valve when the gauge reading reaches 469 psig (33 kgf/cm2G). Then, test for leaks with liquid soap.

To avoid nitrogen entering CAUTION the refrigerant system in a liquid state, the top of the

cylinder must be higher than the bottom when you pres- surize the system. Usually, the cylinder is used in a ver- tical standing position.

80

Manifold gauge	Vacuum pump
	Outlet
	Inlet

Fig. 7-1a Fig. 7-1b

Valve cap

Flare nut

Service port cap

Fig. 7-2

	Manifold valve
Pressure	Lo	Hi
gauge

Charge hose

Cylinder valve

Nitrogen gas cylinder (In vertical standing position)

Open

Suction tube

Close

Open

Outdoor unit

Discharge tube

Close

Open

Liquid tube

Close

Open

Balance tube

Close

Fig. 7-3

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