SG-40MAHB-01: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
10
SYSTEM EVACUATION AND
CHARGING
Refrigerant tubes and indoor coil should be evacuated using the
recommended deep vacuum 500 microns method. The alternate triple
evacuation method may be used if the following procedure is followed.
Always break a vacuum with dry nitrogen.
NOTE: All units (except the 18,000 BTU model) have a Master
Suction and Liquid Line Service Valve.
System Vacuum and Charge
Using Vacuum Pump
1. Completely tighten the flare nuts (A, B, C, D, E). Fully open all
circuits service valves. Connect the manifold gage charge hose to the
charge port of the low side Master service valve to evacuate all circuits
at the same time (see Fig. 8).
2. Connect the charge hose to the vacuum pump.
3. Fully open the low side of the manifold gage (see Fig. 9).
4. Start the vacuum pump.
5. Evacuate using the triple evacuation method.
6. After evacuation is complete, fully close the low side of the manifold
gage and stop the vacuum pump operation.
7. The factory charge, contained in the outdoor unit, is good for up to
25ft. (8 m) of line length.
8. Disconnect the charge hose from the charge connection of the low side
service valve.
9. Securely tighten the service valves caps.
Fig. 8 —Service Valve
Fig. 9 —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
effective way of assuring a system is free of air and liquid water (see Fig.
10).
Fig. 10 —Deep Vacuum Graph
Triple Evacuation Method
Refer to Fig. 11 and proceed as follows:
1. Pump the system down to 500 MICRONS of mercury and allow the
pump to continue operating for an additional 15 minutes.
2. Close the service valves and shut off the vacuum pump.
3. Connect a nitrogen cylinder and regulator to the system and open until
the system pressure is 2 psig.
4. Close the service valve and allow the system to stand for 10 minutes.
During this time, dry nitrogen can diffuse throughout the system
absorbing moisture.
5. Repeat this procedure as indicated in Fig. 11. Afterwards the system
will be free of any contaminants and water vapor.
Fig. 11 —Triple Evacuation Method
Final Tubing Check
IMPORTANT: Ensure the factory tubing on both the indoor and
outdoor unit has not shifted during shipment. Ensure the tubes are
not rubbing against each other or any sheet metal. Pay close
attention to the feeder tubes to ensure the wire ties on the feeder
tubes are secure and tight.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage
or improper operation.
Never use the system compressor as a vacuum pump.
CAUTION
Outdoor Unit
Indoor Unit
Refrigerant
Service Valve
Low Side
High Side
A
B
C
D
Manifold Gage
500 microns
Low side valve
High side valve
Charge hose
Charge hose
Vacuum pump
Low side valve
500
MINUTES
0
1
2
3
4
5
6
7
1000
1500
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
2000
MI
CRONS
2500
3000
3500
4000
4500
5000
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
