Operation Mode; Demand Control; Control Of Ih Energization Without The Compressor In Operation - Mitsubishi Electric PUHY-HP72 Service Handbook

[5-2 Outdoor Unit Control ]
5-2-17

Operation Mode

(1) Indoor unit operation mode
The operation mode can be selected from the following 5 modes using the remote controller.
1 Cooling mode
2 Heating mode
3 Dry mode
4 Fan mode
5 Stopping mode
(2) Outdoor unit operation mode
1 Cooling mode
2 Heating mode
3 Stopping mode
When the outdoor unit is performing a cooling operation, the operation mode of the connected indoor units that are not in the
cooling mode (Stopped, Fan, Thermo-OFF) cannot be changed to heating from the remote controller. If this attempt is mode,
"Heating" will flash on the remote controller. The opposite is true when the outdoor unit is performing a heating operation. (The
first selection has the priority.)
5-2-18

Demand Control

Cooling/heating operation can be prohibited (Thermo-OFF) by an external input to the indoor units.
When DIP SW6-8 is set to ON, the 4-step DEMAND control is enabled.
Eight-step demand control is possible in the system with two outdoor units.
Twelve-step demand control is possible in the system with three outdoor units.
For details, refer to the following page(s). [2-4-7 Various Control Methods Using the Signal Input/Output Connector on Outdoor
Unit]
5-2-19

Control of IH energization without the compressor in operation

IH is used to heat the compressor motor on the stopped outdoor unit to make liquid refrigerant in the compressor evaporate
or to keep liquid refrigerant from flooding the compressor.
Initial power on after power is turned on: Stays on for 12 hours, and then transitions to the operation that is performed while
the compressor is stopped
When the compressor is stopped: Stays on for 30 minutes after the compressor stopped, and then repeats the on-off cycle
at 30-minute intervals
Lit LED1 on the INV board indicates that the INV board is energized by an IH.
HWE18240_GB
All indoor units in operation are in cooling mode.
All indoor units in operation are in heating mode.
All indoor units are in fan mode or stopping mode.
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