Carrier 40GXC, 40GXQ, 38GXQ, 38GXC System Vacuum and Charge, Using Vacuum Pump

!CAUTION

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.

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 procedure outlined below is followed. Always break a vacuum with dry nitrogen.

SYSTEM VACUUM AND CHARGE

Using Vacuum Pump

1.Completely tighten flare nuts A, B, C, D, connect manifold gage charge hose to a charge port of the low side service valve. (See Fig. 15.)

2.Connect charge hose to vacuum pump.

3.Fully open the low side of manifold gage. (See Fig. 16)

4.Start vacuum pump

5.Evacuate using either deep vacuum or triple evacuation method.

6.After evacuation is complete, fully close the low side of manifold gage and stop operation of vacuum pump.

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 0.1 oz. per foot of extra piping up to the maximum allowable length.

8.Disconnect charge hose from charge connection of the low side service valve.

9.Fully open service valves B and A.

10.Securely tighten caps of service valves.

Outdoor Unit		Refrigerant	Indoor Unit
		Low Side		C
	A
				D
	B	High Side
Service Valve

A07360

Fig. 15 ---Service Valve

Manifold Gage
500 microns
Low side valve	High side valve
Charge hose	Charge hose

Vacuum pump

Low side valve

A07361

Fig. 16 ---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. 17)

5000
4500
4000						LEAK IN
3500
						SYSTEM
3000
2500
MICRONS2000						VACUUM TIGHT
1500
						TOO WET
1000
						TIGHT
500
						DRY SYSTEM
0	1	2	3	4	5	6	7
			MINUTES
							A95424

Fig. 17 ---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. 18 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. 18. System will then be free of any contaminants and water vapor.

EVACUATE

BREAK VACUUM WITH DRY NITROGEN

WAIT

EVACUATE

BREAK VACUUM WITH DRY NITROGEN

WAIT

EVACUATE

CHECK FOR TIGHT, DRY SYSTEM (IF IT HOLDS DEEP VACUUM)

RELEASE CHARGE INTO SYSTEM

A95425

Fig. 18 ---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.

38/40GXC(Q)

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