Vacuum And Gas Leakage Inspection - Delta 21UT024C24 Instruction Manual

Floor Ceiling Air-Conditioning Unit
4.4.6 Checking the Pipe Connections for Gas Leaking
For both indoor and outdoor unit side, check the joints for gas leaking by the use of a gas
leakage detector without fail when the pipes are connected.
4.4.7 Heat Insulation on the Pipe Joints (Indoor Side Only)
Stick coupler heat insulation (large and small) to the place where connecting pipes.

4.5 Vacuum and Gas Leakage Inspection

Do not purge the air with refrigerants but use a vacuum pump to vacuum the installation! There
is no extra refrigerant in the outdoor unit for air purging!
4.5.1 Vacuum
(1) Remove the caps of the liquid valve, gas valve and also the service port.
(2) Connect the hose at the low pressure side of the manifold valve assembly to the service
port of the unit's gas valve, and meanwhile the gas and liquid valves should be kept closed
in case of refrigerant leak.
(3) Connect the hose used for evacuation to the vacuum pump.
(4) Open the switch at the lower pressure side of the manifold valve assembly and start the
vacuum pump. Meanwhile, the switch at the high pressure side of the manifold valve
assembly should be kept closed, otherwise evacuation would fail.
(5) The evacuation duration depends on the unit' capacity, generally, 30 minutes for the 24/36K
units, 45 minutes for the 42/48/60 units. And verify if the pressure gauge at the low pressure
side of the manifold valve assembly reads -1.0Mp (-75cmHg), if not, it indicates there is leak
somewhere. Then, close the switch fully and then stop the vacuum pump.
(6) Wait for some time to see if the system pressure can remain unchanged, 5 minutes for the
24K units, 10 minutes for 48/60K units. During this time, the reading of the pressure gauge
at the low pressure side can not be larger than 0.005Mp (0.38cmHg).
(7) Slightly open the liquid valve and let some refrigerant go to the connection pipe to balance
the pressure inside and outside of the connection pipe, so that air will not come into the
Fig.17
CAUTION!
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