Heat Controller VMC12SB-1/VMH12SB-1 User Manual

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Only for training and service purposes

Part 4 Trouble Shooting

• Procedure

(1) Confirm that both the 2-way and 3-way valves

are set to the open position.
– Remove the valve stem caps and confirm that

the valve stems are in the raised position.

– Be sure to use a hexagonal wrench to operate

the valve stems.

(2) Operate the unit for 10 to 15 minutes.

(3) Stop operation and wait for 3 minutes, then

connect the charge set to the service port of
the 3-way valve.
– Connect the charge hose with the push pin to

the service port.

(4) Air purging of the charge hose.

– Open the low-pressure valve on the charge set

slightly to allow air purge from the charge hose.

(5) Set the 2-way valve to the closed position.

(6) Operate the air conditioner at the cooling

cycle and stop it when the gauge indicates
1kg/cm

·g (14 PSI).

(7) Immediately set the 3-way valve to the closed

position.
– Do this quickly so that the gauge ends up indi-

cating 3 to 5kg/cm

·g (42 to 71PSI).

(8) Disconnect the charge set, and mount the 2-

way and 3-way valve’s stem nuts and the ser-
vice port nut.
– Use torque wrench to tighten the service port

nut to a torque of 1.8 kg·m (13 lbf·ft)

– Be sure to check for gas leakage.

Closed

Purge the air

Outdoor unit

Indoor unit

Liquid side

Gas side

Open

2-Way
valve

3-Way
valve

2. Pumping Down