Daikin EWWDC17CJYNN [24/28] Appendix 2 unit start up sequence

Appendix 2: Unit start-up sequence

In the following paragraphs, the unit start-up, management and shutdown procedures are shown. In addition to this, the

compressors loading and unloading strategy is shown.

Unit Startup request

Evaporator and condenser pump startup

Evaporator flow switch consent within 20 s

(manufacturer set)

30s waiting (user set)

PID operation start

30s waiting

Compressors start enabled

PID requires LOAD

PID requires STANDBY

PID requires UNLOAD

NO UNIT ALARM 005

(Evap Flow Alarm)

YES

A new compressor is required

No new compressor

required

The compressor with lower

working hours is selected

Liquid solenoid opening

3s waiting

Compressor Start

Transition confirm

within 10 s

8s compressor unloading

Compressor enabled to load

COMPRESSOR ALARM 008

(Transition fault)

Compressors loading

Compressor stop required

Compressor complete unloading (max 30s)

Luiquid solenoid closing

Low pressure alarm disabling

Expansion valve closing

Line relay opening

Waiting for the evaporating pressure

setpoint is reached (with a maximum time)

No compressor stop

required

Compressors unloading

Unit startup and compressors management