Carrier 42HVM109303 Service Manual page 24

2. Refrigerant charging
Electronic scale
Procedure:
1). Connect the charge hose to the charging cylinder, open the 2-way valve and the 3-way valve
Connect the charge hose which you disconnected from the vacuum pump to the valve at the bottom of
the cylinder. If the refrigerant is R410A, make the cylinder bottom up to ensure liquid charge.
2). Purge the air from the charge hose
Open the valve at the bottom of the cylinder and press the check valve on the charge set to purge the
air (be careful of the liquid refrigerant).
3) Put the charging cylinder onto the electronic scale and record the weight.
4). Open the valves (Low side) on the charge set and charge the system with liquid refrigerant
If the system cannot be charge with the specified amount of refrigerant, or can be charged with a little at
a time (approximately 150g each time) , operating the air conditioner in the cooling cycle; however, one
time is not sufficient, wait approximately 1 minute and then repeat the procedure.
5).When the electronic scale displays the proper weight, disconnect the charge hose from the 3-way
valve's service port immediately
If the system has been charged with liquid refrigerant while operating the air conditioner, turn off the air
conditioner before disconnecting the hose.
6). Mounted the valve stem caps and the service port
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