Mitsubishi Electric CITY MULTI PUHY-400YMF-C Service Handbook page 125

(3) Refrigerant adjustment in heating season (Flow chart)
PUHY-(P) 400·500 YMF-C
Start
Adjustment
1
Run all the indoor units in the
heating condition in the test run
mode.
Note: 1
Note: 2
2
Has the operating
condition stabilized?
Note: 3
3
Is the
accumulator's liquid level
AL = 0?
6
Charge with small amounts of
refrigerant at a time through the
low pressure service port.
After adjusting the refrig-
erant volume, run for 5
minutes and judge the AL.
8
Did the liquid level
change from AL = 0 to
AL = 1?
10
Finish charging with refrigerant.
12
Determine the difference between
the volume of refrigerant needed for
heating and the volume needed for
cooling and charge with that amount.
Note: 5
13
Note: 6
Turn on switches No. 1, 2, 4, 5 and 6
of the self-diagnosis switch (SW1),
switching to the mode in which the
liquid level is displayed by the LED.
After adjusting the refrig-
erant volume, run for 5
minutes and judge the AL.
14
Is the
accumulator's liquid level
AL = 1?
Note: 7
15
Turn all of switches of
SW1 OFF.
Adjustment
complated.
AL = 1 or 2
4
Is the
accumulator's liquid level
AL = 1?
5
Is the accumulator's
liquid level AL=0 when just one indoor
unit is running.
7
Drain out small amounts of
refrigerant at a time from the low
pressure service port.
9
Did the liquid level
change from AL = 1 to
AL = 0?
11
Finish draining out refrigerant.
* If adjustment of the refrigerant volume was done by heating operation, it
is possible that accumulation of refrigerant due to the lengthened piping
could have a great influence, so it is recommended that operation be
checked during the cooling season.
Note: Do not let the drained out refrigerant escape into the atmosphere.
Readjust.
-122-
Note: 3
AL = 2
Note: 4
Adjustment is
not necessary.
16
Drain out small amounts of
refrigerant at a time from the low
pressure service port.
17
Did the liquid level
change from AL = 2 to
18
Finish draining out refrigerant.
19
Draining out approximately 5 kg
of refrigerant.
YES
NO
After adjusting the refrig-
erant volume, run for 5
minutes and judge the AL.
AL = 1?
Adjustment
complated.