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20
Manifold Gage
500 microns
Low side valve
High side valve
Charge hose
Charge hose
Vacuum pump
Low side valve
A07361
Fig. 29 -- Manifold
Deep Vacuum
Method
The deep vacuum method requires a vacuum pump capable of
pulling a vacuum of 500 microns and a vacuum gage capable of
accurately measuring this vacuum depth. The deep vacuum method
is the most positive way of assuring a system is free of air and
liquid water. (See Fig. 30)
500
MINUTES
01234567
1000
1500
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
2000
MICRONS
2500
3000
3500
4000
4500
5000
A95424
Fig. 30 -- Deep Vacuum Graph
Triple Evacuation
Method
The triple evacuation method should only be used when vacuum
pump is only capable of pumping down to 28 in. of mercury
vacuum and system does not contain any liquid water.
Refer to Fig. 31 and proceed as follows:
1. Pump system down to 28 in. of mercury and allow pump to
continue operating for an additional 15 minutes.
2. Close service valves and shut off vacuum pump.
3. Connect a nitrogen cylinder and regulator to system and
open until system pressure is 2 psig.
4. Close service valve and allow system to stand for 1 hr. Dur-
ing this time, dry nitrogen will be able to diffuse throughout
the system absorbing moisture.
5. Repeat this procedure as indicated in Fig. 31. System will
then be free of any contaminants and water vapor.
CHECK FOR TIGHT, DRY SYSTEM
(IF IT HOLDS DEEP VACUUM)
EVACUATE
BREAK VACUUM WITH DRY NITROGEN
WAIT
EVACUATE
RELEASE CHARGE INTO SYSTEM
BREAK VACUUM WITH DRY NITROGEN
EVACUATE
WAIT
A95425
Fig. 31 -- Triple Evacuation Method
To Start the Unit:
1. If the outdoor unit is equipped with a crankcase heater, turn
on the indoor and outdoor disconnect switches to supply
power the system 12 hours before starting the system.
2. Release charge into the system by opening (back--seating)
liquid and suction line service valves.
3. Set the wireless remote control or wired remote control be-
low ambient temperature. Operate the unit for 15 minutes.
4. Refer to Table 5 to determine if additional charge is re-
quired. Also, if you have a long line application, refer to the
Duct Free Long Line Application Guide to determine the
additional charge that is required beyond 25 ft (7.6 m).
5. Calculate the total additional charge required and weigh in.
6. Charge should be added as liquid (not gas) slowly and care-
fully to low side to avoid liquid slugging.
40QAC/38HDR -- 40QAQ/38QR
R