9
REFRIGERANT LINES
IMPORTANT: Both refrigerant lines must be insulated separately.
Table 2 lists the pipe sizes for the indoor unit. Refer to the outdoor unit installation instructions for other allowed piping lengths and
refrigerant information.
SYSTEM EVACUATION AND
CHARGING
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
!
Refrigerant tubes and indoor coil should be evacuated using the
recommended deep vacuum method of 500 microns. The alternate
triple evacuation method may be used if the following procedure is
followed. Always break a vacuum with dry nitrogen.
System Vacuum and Charge
Using Vacuum Pump
1 Completely tighten flare nuts on the line set at both the
indoor and outdoor units. DO NOT open the service valves
on the outdoor unit for the new installation or the
replacement unit. Open the service valves on the outdoor
unit if repairs have been made to the refrigerant sealed
system. Connect the manifold gauge low pressure hose to
the charge port of the gas side service valve (see Fig. 6).
2 Connect the charge hose to the vacuum pump.
3 Fully open the low pressure valve of manifold gage (see
Fig. 7).
4 Start the vacuum pump.
5 Evacuate using deep vacuum or triple evacuation method.
6 After evacuation is complete, fully close the pressure valve
side of 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. If vacuum is complete per
Fig. 10 or 11, open service valves to release factory charge
into the system.
8 Disconnect the charge hose from the charge connection of
the gas side service valve.
9 Securely tighten the service valve caps.
Outdoor Unit
Indoor Uni
Refrigerant
Service Valve
Gas Side
Liquid Side
A
B
C
D
Fig. 6 – Service Valve
Manifold Gage
500 microns
Low pressure valve
High side valve
Low pressure hose
Charge hose
Vacuum pump
Gas side valve
Fig. 7 – 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. 8).
500
MINUTES
01234567
1000
1500
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
2000
MICRONS
2500
3000
3500
4000
4500
5000
Fig. 8 – Deep Vacuum Graph
Triple Evacuation Method
The triple evacuation method should be used. Refer to Fig. 9 and
proceed as follows:
1 Pump the system down to 1500 microns 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 dry nitrogen cylinder and regulator to the system
and break vacuum until the system reaches 2 psig.
4 Close the service valve and allow the system to stand for
1hr. During this time, the dry nitrogen can diffuse
throughout the system absorbing moisture.
5 Pump the system down to 1000 microns.
6 Break the vacuum with dry nitrogen (2 psig).
7 Pump the system down to 500 microns.
8 Perform the hold test for 30 minutes.
CHECK FOR TIGHT, DRY SYSTEM
(IF IT HOLDS DEEP VACUUM)
EVACUATE TO 1500 MICRONS
EVACUATE TO 500 MICRONS MINIMUM (HOLD FOR 30 MINUTES)
RELEASE CHARGE INTO SYSTEM BY OPENING VALVES COMPLETELY
BREAK VACUUM WITH DRY NITROGEN TO 2 PSIG
EVACUATE TO 1000 MICRONS
BREAK VACUUM WITH DRY NITROGEN TO 2 PSIG
Fig. 9 – Triple Evacuation Method
Final Tubing Check
IMPORTANT: Check to be certain factory tubing on both
indoor and outdoor unit has not shifted during shipment.
Ensure tubes are not rubbing against each other or any sheet
metal. Pay close attention to feeder tubes, making sure wire ties
on feeder tubes are secure and tight.
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