Carrier 40MUAA Installation Instructions Manual Download Page 15

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40MUAA: Installation Instructions

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.

Step 8 - Evacuate Coil and Tubing System

Refrigerant tubes and the indoor coil should be evacuated using the
recommended 500 microns deep vacuum method. The alternate triple
evacuation method may be used if the procedure outlined below is
followed.

NOTE: Always break a vacuum with dry nitrogen.

Using Vacuum Pump

1. Completely tighten flare nuts A, B, C, D, connect the manifold gage

charge hose to a charge port of the low side service valve (see Fig.
37).

2. Connect the charge hose to vacuum pump.
3. Fully open the low side of manifold gage (see Fig. 38 ).
4. Start the vacuum pump.
5. Evacuate using either the deep vacuum or triple evacuation method.
6. After evacuation is complete, fully close the low side of manifold

gage and stop the vacuum pump operation.

7. The factory charge contained in the outdoor unit is good for up to 25

ft. (8 m) of line length. For refrigerant lines longer than 25 ft. (8 m),
add refrigerant, up to the allowable length.

8. Disconnect the charge hose from the charge connection of the low

side service valve.

9. Fully open service valves B and A.
10. Securely tighten the service valve caps.

A220816

Fig. 37 —Service Valve

A220790

Fig. 38 — Manifold

Evacuation

Evacuation of the system removes air or nitrogen (non-condensables) as well
as moisture. A proper vacuum will assure a tight, dry system before charging
with refrigerant. The two methods used to evacuate a system are the deep
vacuum method and the triple vacuum method.

Deep Vacuum Method

The deep vacuum method requires a vacuum pump capable of pulling a
vacuum of 500 microns and a vacuum gauge 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 moisture.

NOTE: DO NOT add a filter line drier.

A220817

Fig. 39 —Deep Vacuum Graph

Triple Evacuation Method

The triple evacuation method should be used when vacuum pump is not
capable of pumping down to 500 microns and system does not contain
any liquid water. Refer to Fig. 40 and proceed as follows:

1. Attach refrigeration gauges and evacuate 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 flow

nitrogen until system pressure is 2 psig.

4. Close service valve and allow system to stand for 1 hour. During this

time, dry nitrogen can diffuse throughout the system absorbing
moisture.

5. Repeat this procedure as indicated in Fig. 40. The system should

now be free of any contaminants and water vapor.

A220818

Fig. 40 —Triple Evacuation Method

Final Tubing Check

Check to be certain factory tubing on both the 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 the feeder tubes, making
sure wire ties on 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

500

1000

1500