Specifications

130 RK0YG302 © Danfoss 05/2007
Application
The controller and valve can be used where there are require-
ments to accurate control of superheat and temperature in con-
nection with refrigeration.
E.g.:
• Processing plant (water chillers)
• Cold store (air coolers)
• A/C plant
Advantages
• The evaporator is charged optimally – even when there are
great variations of load and suction pressure.
• Energy savings – the adaptive regulation of the refrigerant injec-
tion ensures optimum utilisation of the evaporator and hence a
high suction pressure.
• The superheating is regulated to the lowest possible value at
the same time as the media temperature is controlled by the
thermostat function.
Functions
• Regulation of superheat
• Temperature control
• MOP function
• ON/OFF input for start/stop of regulation
• Input signal that can displace the superheat reference or the
temperature reference
• Alarm if the set alarm limits are exceeded
• Relay output for solenoid valve
• PID regulation
System
The superheat in the evaporator is controlled by one pressure
transmitter P and one temperature sensor S2.
The expansion valve is with step motor of the type ETS.
If temperature control is required, this can be accomplished via
a signal from temperature sensor S3 placed in the air ow before
the evaporator. The temperature control is an ON/OFF thermostat
that opens for the liquid ow when refrigeration is required – the
ETS valve opens and the thermostat relay cuts in.
For safety reasons the liquid ow to the evaporator must be cut
o if there is power failure for the controller. As the ETS valve is
provided with step motor, it will remain open in such a situation.
There are two ways of coping with this situation:
- Mounting of a solenoid valve in the liquid line
- Mounting of battery backup for the valve
EKC 316A
EKC 316A