Midea M2OC-18HFN1-M, Service Manual

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turn off the vacuum pump, and confirm that the
gauge needle does not move (approximately 5
minutes after turning off the vacuum pump).
5). Disconnect the charge hose from the vacuum
pump.
2. Refrigerant charging
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. Use torque wrench to tighten the
service port cap to a torque of 18N.m. Be sure
to check for gas leakage.
7. Electronic Function
7.1 Abbreviation
T1: Indoor ambient temperature
T2: Coil temperature of indoor heat exchanger
middle.
T2B: Coil temperature of indoor heat exchanger
outlet.
T3: Pipe temperature of outdoor heat exchanger
T4: Outdoor ambient temperature
Tp: Compressor discharge temperature
7.2 Electric control working environment.
7.2.1 Input voltage: 230V.
7.2.2 Input power frequency:60Hz.
7.2.3 Indoor fan normal working amp. is less than
1A.
7.2.4 Outdoor fan. Normal working amp. is less
than 1.5A.
7.2.5 Four-way valve normal working amp. is less
than 1A.
7.3 Main Protection
7.3.1 Three Minutes Delay at restart for
compressor.
---- 1min delay for the 1
st
time start-up and 3
minutes delay for others.
7.3.2 Temperature protection of compressor
discharge.
When the compressor discharge temp. is getting
higher, the running frequency will be limited as
below rules:
----If 102
℃
<Tp<115
℃
, decrease the frequency to
the lower level every 2 minutes till to F1.
---If Tp>115
℃
for 10 seconds, the compressor
will stop and restart till Tp<90
℃
.
7.3.3 Fan Speed is out of control(DC fan
motor).