Evacuation - Heat Controller DMH18DB-1 Service Manual

Checking the Drainage, Forming the Pipings and Long Pipe Setting

Evacuation

1. Connect the charge hose end described in the pre-
ceding steps to the vacuum pump to evacuate the
tubing and indoor unit.
Confirm the "Lo" knob of the manifold valve is open.
Then, run the vacuum pump.
The operation time for evacuation varies with tubing
length and capacity of the pump.
[Each Room] The vacuum pump must be operated
less than 0.8torr of the gage pressure.
2. When the desired vacuum is reached, close the "Lo"
knob of the manifold valve and stop the vacuum
pump.
Finishing the job
1. With a service valve wrench, turn the valve stem of
liquid side valve counter-clockwise to fully open the
valve.
2. Turn the valve stem of gas side valve counter-clock-
wise to fully open the valve.
3. Loosen the charge hose connected to the gas side
service port slightly to release the pressure, then
remove the hose.
4. Replace the flare nut and its bonnet on the gas side
service port and fasten the flare nut securely with an
adjustable wrench. This process is very important to
prevent leakage from the system.
5. Replace the valve caps at both gas and liquid side
service valves and fasten them tight.
This completes air purging with a vacuum pump.
The air conditioner is now ready for test running.
NOTICE
: Repeat evacuation procedure for each indoor
unit.
32 Multi type Air Conditioner
Outdoor unit
Manifold valve
Pressure
Lo Hi
gauge
Open Close
Vacuum pump
Indoor unit