Mitsubishi Electric PQRY-P200YEM-A Service Handbook page 70

(2) Refrigerant amount
1 Checking the operating condition
Operate all the indoor units on cooling or on heating, checking the discharge temperature, sub-cooling (BC contr-
oller), low pressure saturation temperature, inlet temperature, shell bottom temperature, liquid level, liquid step,
etc. and rendering an overall judgment.
Note :
Depending on the operating state, AL = 0 has the meaning does not mean that there is insufficient refrigerant.
1 Outlet temperature is high. (110¡C or higher)
2 Low pressure saturation temperature is extremely low.
3 Inlet superheating is high (if normal, SH = 20 deg or lower).
4 Shell bottom temperature is high (the difference with the low pressure saturation
temperature is 70 deg. or greater)
5 Shell temperature is low (the difference with the low pressure saturation tem-
perature is 10 deg. or lower).
6 Liquid level AL = 2
2 Check the refrigerant volume by self-diagnosis using the LED.
Set the self-diagnosis switch (SW1) as shown below and check the past information (history) concerning the
refrigerant volume.
Set SW1 as shown in he figure at right.
If LD8 lights up, it indicates the refrigerant charge abnormal delay state just before emergency stop due to refri-
gerant overcharge (1500).
3 Additional refrigerant charge volume
At the time of shipping from the factory, the heat source unit is charged with the amount of coolant shown in the
following table, but since no extension piping is included, please carry out additional charging on-site.
Heat source unit model name
Refrigerant charge volume
Calculation formula
Calculate the additional refrigerant volume by calculating the size of the extension liquid piping and its length (units: m).
Additional refrigerant volume
In the calculation results, round up fractions smaller than 0.01 kg. (Example: 18.54 kg → 18.6 kg)
(α Calculation Table)
Total capacity of
connected indoor units
~ 160
161 ~
Caution :
When charging with refrigerant, be sure to charge from the liquid side. If charging from the gas side, it will
cause the refrigerant composition to change inside the unit and the composition of the refrigerant remaining
in the canister will also change.
Condition
1 2 3 4 5 6 7 8 9 10
ON
PQRY-P200
7.5kg
(kg) = (0.12 × L ) + (0.06 × L
1
α
1.5
2.0
–69–
Refrigerant volume tends toward
insufficient.
Rifrigerant volume tends toward
overcharge.
PQRY-P250 PQHY-P200
8.5 kg 7.0 kg
) + (0.024 × L ) + α
2 3
L : Length of ø12.7 liquid pipe (m)
1
L : Length of ø9.52 liquid pipe (m)
2
L : Length of ø6.35 liquid pipe (m)
3
α:
Refer to the calculation table. .
Judgment
PQHY-P250
8.0 kg