External display
Termination
Connect H-R
The capacity from the
digital scroll compressor
The capacity is divided into period times as "PWM period time". 100% capacity is delivered when cooling takes place for the whole
period.
An off time is required by the capacity control valve within the period and an on time is also permitted. There is "no cooling" when the
valve is on.
The controller itself calculates the capacity needed and will then vary it according to the cut-in time of the capacity control valve.
A limit is introduced if low capacity is needed so that the cooling does not go below 10%. This is because the compressor can cool
itself. This value can be increased if necessary.
Refrigeration / No refrigeration
Copeland Stream compressor
The signal can also be used to control one stream compressor with one unloading valve (4 cylinders version).
The compressor capacity is distributed by up to 50% for one relay and the remaining 50-100% for the unloader. The unloader is con-
nected to DO5 or DO6.
Bitzer CRII
The pulse signal can also be used to control one of the CRII with 2 unloaders (4 cylinders version).
Compressor capacity can be controlled from 10 to 100% depending on the pulsation of the unloaders. The unloader is connected to
DO5 or DO6.
Unloader 2 follows unloader 1
but is offset a ½ period.
AK-PC 551
Dimensions
Important!
Termination
Connect H-R
Period time
Min. capacity
Instructions RI8PZ4ML © Danfoss 06/2015
Only DO5 or DO6
Unloader 1
Unloader 2
3