Operation Characteristics In Relation To The Refrigerant Charge; Operation Check - Mitsubishi Electric City Multi PURY-HP-TNU-A Série Manuel D'installation

Setting content
SW6-1
SW6-2
SW6-3
SW6-4
High static pressure setting
SW6-5
SW6-6
SW6-7 Low-noise mode selection
SW6-8 Selection of Low-noise or Demand
SW6-9
Selection of Diagnostic display or Function
detail setting
SW6-10
* Do not change the factory settings of SW5-3 through SW5-8.
* Unless otherwise specified, leave the switch to OFF where indicated by "–," which may be set to OFF for a reason.
*1
SW6-5: ON
SW6-4: ON 80 Pa
SW6-4: OFF 30 Pa
*2
SW6-9: ON LED (round type) No. 0 to 1023
SW6-9: OFF Function setting No. 0 to 1023

11-3. Operation characteristics in relation to the refrigerant charge

It is important to have a clear understanding of the characteristics of refrigerant and the operation characteristics of air conditioners before
attempting to adjust the refrigerant charge in a given system.
・During cooling operation, the amount of refrigerant in the accumulator is the smallest when all indoor units are in operation.
・During heating operation, the amount of refrigerant in the accumulator is the largest when all indoor units are in operation.
・Refrigerant undercharge creates a tendency for the discharge temperature to rise.
・Changing the amount of refrigerant in the system while there is refrigerant in the accumulator has little effect on the discharge temperature.
・The higher the high pressure level, the more likely it is for the discharge temperature to rise.
・The lower the low pressure level, the more likely it is for the discharge temperature to rise.
・When the amount of refrigerant in the system is adequate, the compressor shell temperature is 10 to 60ºC (50 to 140ºF) higher than the low-
pressure saturation temperature. If the temperature difference between the compressor shell temperature and low-pressure saturation
temperature is 5ºC (41ºF) or less, refrigerant overcharge is suspected.

11-4. Operation check

The following symptoms are normal and do not indicate a problem.
Events
The auto vane automatically switches air flow direction.
The fan speed automatically changes during heating
operation.
The fan stops during heating operation.
The fan keeps running after the unit has stopped.
At the beginning of heating operation, the fan cannot be
manually set.
When the main power is turned on, the display as shown
right appears on the remote controller for about five
minutes.
The drain pump keeps running after the unit has
stopped.
The indoor unit emits noise when switching from heating
to cooling and vice versa.
Immediately after startup, the indoor unit emits the
sound of liquid flowing.
WT09112X02
OFF
–
–
–
Refer to *1.
–
Performance priority
Low-noise (Night)
Refer to *2.
SW6-5: OFF
60 Pa
0 Pa
SW6-10: ON
Display on remote Cause
controller
Normal display The auto vane may switch over to horizontal air flow operation from vertical air flow operation in cooling mode if
the vertical air flow operation has been running for one hour. At defrost in heating mode or immediately after
heating start-up/shutdown, the auto vane automatically switches to horizontal air flow for a short time.
Normal display The fan operates at Very Low speed when the thermostat is turned off, and automatically changes over to the
preset speed according to the timer setting or refrigerant temperature when the thermostat is turned on.
"Defrost" The fan remains stopped during the defrost cycle.
No display After the unit has stopped during heating operation, the fan operates for one minute to exhaust heat.
"Stand By" The fan operates at Very Low speed for five minutes after heating operation starts or until the refrigerant
temperature reaches 35°C (95°F), then the fan operates at Low speed for two minutes, and finally the fan
operates at the preset speed.
"HO" or "PLEASE The system is starting up. Wait until "HO" or "PLEASE WAIT" stops blinking and goes off then try again.
WAIT" blinks.
No display The drain pump remains in operation for three minutes after the unit in cooling mode has stopped.
The drain pump goes into operation when drain water is detected, even when the unit is stopped.
Normal display This is a normal sound of the refrigerant circuit operating properly.
Normal display Unstable flow of the heating medium produces a sound. This is temporary and does not imply a problem.
Setting
ON
– –
– –
– –
Refer to *1.
– –
Low-noise priority
Demand
Refer to *2.
SW6-10: OFF
LED (7seg) No. 1024 to 2047
LED (7seg) No. 0 to 1023
GB-39
Switch setting timing
–
–
–
Before being energized
–
Any time after being energized
Before being energized
Any time after being energized