Danfoss AK-PC 351 User Manual page 4

Condenser
Fan control
The fans can be controlled incrementally using the controller's
relays, or they can be speed-controlled via the controller's
analogue output.
Speed control can be via a frequency VLT-type transformer.
If the fans have EC motors, the 0-10 V signal can be used directly.
Control
Regulation is carried out based on a signal from the Pc pressure
transmitter or an S7 media temperature sensor. The signal is com-
pared with the regulation reference.
The regulation reference can originate from one or more of the
following functions:
• Fixed reference
• Variable reference, which follows the outdoor temperature.
When the outdoor temperature drops, the reference will drop
by a corresponding amount.
This variable reference requires the installation of an Sc3
outdoor temperature sensor. The sensor must be positioned
so that it registers the correct outdoor temperature. In other
words, it must be shielded from direct sunlight and located
near the airway of the condenser.
This regulation requires setting a min. and max. reference,
so that the regulation process is kept within the given limits.
Media temperature
If controlling a media temperature, the control sensor
must be set to S7. This temperature sensor must be located
in the desired medium.
High-pressure monitoring can occur with an external, high-pres-
sure switch on DI8.
4 User Guide RS8GZ302 © Danfoss 2015-06
Max. ref.
Min. ref.
AK-PC 351