Midea MFE-60ARN1-RB4W Service Manual page 17

5.3.2 Piping connection
5.3.2.1 Connecting Of Refrigerant Pipe
a) Only the correctly installing of indoor and outdoor unit done, can the refrigerant
pipe be connected.
b) The cut-off valves are completely close before ex-work. Before connecting the
refrigerant pipe, be careful to check whether the valves are completely close.
c) The connecting procedure of refrigerant pipe: first, unscrew the two valves on the
outdoor unit and the pipe-jointing nut on the indoor unit(please keep them
carefully). Please connect the refrigerant pipe according to the manual, the
pipe-jointing nut should be screw tightly and no leakage. Note: you need two
wrenches to make balance.
d) When the connecting of refrigerant pipe is finished, before power on the system,
you should vacuum the indoor unit through the maintenance port on the cut-off
valves, or open the high-pressure valve, and exhaust the air through the
maintenance port on the low-pressure valve(closed). It will take about ten
seconds. Then screw tightly the maintenance port. (When supplement the
refrigerant, fill through the maintenance port of the low-pressure valves on the
outdoor unit).
e) Open all the valves completely before power on the system, or it will be sick for
low efficiency.
f) Gas leak check. Make sure no gas from connections with leak detector or soap
water.
5.3.2.2 Pipe Connecting Procedures
Completely shut the cut-off valves of the outdoor unit (as ex-work status). Unscrew the
nuts on the cut-off valves and immediately connect the reamer joint (in 5 minutes). If it last
too long, dust, vapor and other obstacles may enter the pipe and cause trouble later on.
Before connecting the pipe, the air in the pipe should be removed in advance by releasing
refrigerant R-410A.
Notes for the bendable pipe
a. The bendable pipe should be used on the indoor side;
b. Bend angel may not exceed 90 degrees;
c. The bend location should be made on the center of the pipe if possible, as for bend
radius, the bigger the better;
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