Midea MOB31-12HFN1-QRD0GW, Service Manual

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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 the 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) Operate the air conditioner at the cooling
mode.
5) Open the valves (Low side) on the charge set
and charge the system with liquid refrigerant.
6).When the electronic scale displays the proper
weight (refer to the table), disconnect the charge
hose from the 3-way valve’s service port
immediately and turn off the air conditioner before
disconnecting the hose.
7). Mount the valve stem caps and the service
port
Use torque wrench to tighten the service port
cap to a torque of 18N.m.
Be sure to check for gas leakage.
5.5 Adding the refrigerant after running
the system for many years
Procedure:
1). Connect the charge hose to the 3-way service
port, open the 2-way valve and the 3-way valve.
Connect the charge hose 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) Operate the air conditioner at the cooling
mode.
5) Open the valves (Low side) on the charge set
and charge the system with liquid refrigerant.
6).When the electronic scale displays the proper
weight (refer to the gauge and the pressure of the
low side), disconnect the charge hose from the
3-way valve’s service port immediately and turn
off the air conditioner before disconnecting the
hose.
7). Mount the valve stem caps and the service
port
Use torque wrench to tighten the service port
cap to a torque of 18N.m.
Be sure to check for gas leakage.
5.6 Re-installation while the indoor unit
need to be repaired
1. Collecting the refrigerant into the outdoor
unit
Procedure
1). Confirm that both the 2-way and 3-way valves
are set to the opened position
Remove the valve stem caps and confirm that the
valve stems are in the opened position.
Be sure to use a hexagonal wrench to operate the
valve stems.