Freezing Cycle System Protective Control; Crankcase Heater; Inching Prevention; Cooling Overload Protection Control - Mitsubishi Heavy Industries SCM60ZF-S Technical Manual

Inverter multi-split system room air-conditioner
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(5) Freezing cycle system protective control

(a) Operating conditions: When both of following conditions have continued for more than 5 minutes later than 5 minutes
1) Indoor command speed is higher than 0 rps
2) During cooling, dehumidifying: Indoor heat exchanger temperature - Room temperature > –4°C
(b) Detail of operation
1) Indoor unit
The command speed is forced to operate at 16 rps.
2) Outdoor unit
For 5 minutes after the main controller starts, the outdoor unit speed is 12 (10) rps. After 5 minutes, the outdoor unit speed
is 64 (30) rps, up until 8 minutes of operation. After 8 minutes, the outdoor unit speed is 12 (10) rps, up until 13 minutes
of operation. After 13 minutes, the outdoor unit speed is 64 (30) rps, up until 16 minutes of operation.
(c) Restoration conditions: When the condition becomes either conditions shown below
During cooling, dehumidifying: Th
Notes (1) Th
-R
(X): After this control starts, the indoor heat exchanger temperature after X minutes.
I
1
(2) This control is valid when the room air temperature is in the range of 10 to 40°C at cooling and dehumidification operation.
(3) Values in ( ) are SCM60, SCM80.

(6) Crankcase heater

(a) Operating conditions (When all the conditions below are satisfied)
1 After the operation mode is changed to stop and the decision speed becomes 0 rps continuously for 30 minutes.
2 When the temperature detected by the outdoor temperature sensor is 10°C or lower after the compressor stops.
(b) Detail of operation
The crankcase heater operates, warming up the compressor, then refrigerant begins circulating smoothly when the cooler
starts its heating operation, and heating begins.
(c) Restoration conditions
When the temperature detected by the outdoor temperature sensor reaches 12°C or higher, or the operation mode changes
from stop to cooling or heating.

(7) Inching prevention

When the compressor becomes to the thermo operation within 3 minutes since operation start or becomes dehumidifying operation,
the operation is continued with the indoor command speed of 16 rps forcibly.

(8) Cooling overload protection control

During cooling operation, if the outdoor unit is operating at a decision speed other than 0 rps and the outdoor temperature is 39°C
(SCM40 type: 37°C) or more for 30 continuous seconds, current safe control is performed by turning the outdoor fan motor is
forcedly set on 6 th speed. Operation is restored when the outdoor temperature is 38°C (SCM40 type: 36°C) or less.
after the start of operation.
(5) < = – 2°C, Th
-R
(8) – Th
-R
I
1
I
1
-
-R
(16) – Th
-R
I
1
I
60
-
(13) < = – 2°C
1

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