Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 146

-11- Method of Cooling the Control Box <PQHY/PQRY>
The control box of the PQHY/PQRY models of units is equipped with a refrigerant evaporator to cool the heat that is gen-
erated within the control box.
It supplies refrigerant to the evaporator during inverter operation and also cools the inside of the unit and the control box
by operating the cooling fan inside the control box.
(1) Cooling fan control
1) If the heatsink fin temperature exceeds 80°C [176°F], cooling fan comes on and stays on until the temperature goes
below 80°C [176°F]. During this time, inverter startup is prohibited.
2) While the inverter is in operation, the fan always stays on.
3) Once the cooling fan comes on, it stays on for at least five minutes.
(2) LEV2 control
1) LEV2 control range
0 LEV2 100 pulses
2) LEV2 control method
Refer to the table below.
[During cooling only or cooling main operation]
SHB=THINV-Te(Evaporating
temperature)
6°C[11°F]
SHB < 6°C[11°F]
-
[During heating only or heating main operation]
Evaporating temperature
Te
9°C[48°F]
7°C[45°F]
< 9°C[48°F]
Te < 7°C[45°F]
-
THHS
55°C[131°F]
SHB
THHS < 55°C[131°F]
55°C[131°F]
THHS < 55°C[131°F]
SHB=THINV-Te(Evaporating
temperature)
Te -
Te -
6°C[11°F]
SHB < 6°C[11°F]
-
- 137 -
LEV2
THHS Up
Down
THHS Down
Down
- Down
THHS
-
-
55°C[131°F]
SHB
THHS < 55°C[131°F]
55°C[131°F]
THHS < 55°C[131°F]
-
[ VII Control ]
LEV2
Up
Up
THHS Up
Down
THHS Down
Down
Down