Refrigerant Volume Adjustment Mode Operation - Mitsubishi Electric CITY MULTI PUHY-400YMF-B Service Handbook

[3] Refrigerant Volume Adjustment Mode Operation

(1) Procedure
Depending on the operating conditions, it may be necessary either to charge with supplementary refrigerant, or to
drain out some, but if such a case arises, please follow the procedure given below.
Switching the function select switch (SW2-4), located on the outdoor unit's control board, ON starts refrigerant
1
volume adjustment mode operation and the following operation occurs. (Refrigerant recovery mode and oil recovery
mode will be invalid.)
2
Additionally, if the LED monitor display switch (SW1) on the outdoor unit's control board is set to
the accumulator's liquid level is indicated by the LED lighting position.
AL = 0 (No fluid in accumulator)
AL = 1 (Liquid in accumulator)
AL = 2 (Overcharge)
Note 1: Even if AL = 1 for a short time after operation in the refrigerant volume adjustment mode starts, as
time passes (as the refrigeration system stabilizes), it may change to AL = 0.
1 1 1 1 1 If it is really AL = 1
Cases where AL = 1, TH5 - TH7 in the outdoor unit is 5 deg. or greater and the SH of all indoor units is 6 ~ 13 deg.
2 2 2 2 2 Cases where AL = 1 now, but there is a possibility that it will change to AL = 0 as time passes.
TH5 - TH7 in the outdoor unit is not 5 deg., or the SH of at least one of the indoor units is not deg.
Note 2: A refrigerant volume adjustment performed in the cooling mode must be done with a gauge reading of
2
14 kg/cm G (1.37 MPa) or higher.
If the pressure does not reach 14 kg/cm
Note 3: In cooling mode, use TH11, TH12, TH5, TH7 and Tc (Saturation temperature of pressure sensor data of
63HS) to adjust the refrigerant volume. TH11, TH12, TH5 and TH7 can be displayed using the LED
monitor display switch (SW1) on the outdoor unit's control board.
Note 4: Judgment by the AL is at best only a rough guideline. Please do not add refrigerant based on the AL
reading alone. (Be sure to obtain calculations of the correct amount before adding refrigerant.)
TH11 LED monitor display Switch
1 2 3 4 5 6 7 8 9 10
ON
TH7 LED monitor display Switch
1 2 3 4 5 6 7 8 9 10
ON
Using these, judge TH1, Tc - TH5 and Tc - TH7.
In cases where cooling is being done in the refrigerant volume adjustment mode, if 2 above applies, please
A
perform accumulator level AL judgment after waiting until TH5 - TH7 in the outdoor unit is at 5 deg. or higher
and the SH of all the indoor units reaches 2 ~ 5 deg.
Treatment
For the SH of indoor units, turn the LED monitor display switch for the outdoor unit ON, then monitor by the
C
lighting position of the LED.
2
G (1.37 MPa), adjust in the heating mode.
TH12 LED monitor display Switch
1 2 3 4 5 6 7 8 9 10
ON
63HS LED monitor display Switch
1 2 3 4 5 6 7 8 9 10
ON
–122–
1 2 3 4 5 6 7 8 9 10
ON
TH5 LED monitor display Switch
1 2 3 4 5 6 7 8 9 10
ON
Tc LED monitor display Switch
1 2 3 4 5 6 7 8 9 10
ON
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