Mitsubishi Electric CITY MULTI PUHY-P200YEM-A Service Handbook page 74

(2) Refrigerant Volume
1) Checking the Operating Condition
Operate all the indoor units on cooling or on heating, checking the discharge temperature, sub-cooling, low pres-
sure saturation temperature, inlet temperature, shell bottom temperature, liquid level, liquid step, etc. and rendering
an overall judgment.
1 Outlet temperature is high. (100°C or higher)
2 Low pressure saturation temperature is extremely low.
3 Inlet superheating is high (if normal, SH = 20 K or lower).
4 Shell bottom temperature is high (the difference with the low pressure saturation
temperature is 60 K or greater)
5 Shell temperature is low (the difference with the low pressure saturation tem-
per ature is 5 K or lower).
6 Liquid level AL=2 (Determined based on the extent of overheating of discharged refrigerant)
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 LD1 lights up, it indicates the refrigerant charge abnormal delay state just before emergency stop due to refriger-
ant overcharge (1500).
Condition
1 2 3 4 5 6 7 8 9 10
ON
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Judgement
Refrigerant volume tends toward
insufficient.
Rifrigerant volume tends toward
overcharge.