PID refrigeration control


Thread Starter

Thomas Allen

I am looking for a PID control valve that I can control with an Omron E5CK controller. I intend to control evaporator temperature. The evaporators use ammonia and other refrigerants. The application is in commercial warehouse systems. Does anyone have any recommendations?
Hi Thomas,
I'm not quiet sure what you mean by "PID control valve".
If it is a valve with on board PID control, it don't really know much.
But you can get a pid controller with an analog inout this will be the temperature, and an analog output 4-20mA that can controll thee valve position.
There are plenty of Valve's that will take a
4-20mA signal to controll position.

Sorry if it's not much help.

Depending on line size(s), allowable pressure drop across valve, etc., check belimo or spartan peripheral devices' websites. I'll be surprised if you can't find something there.

Manish Okhade

I dont think u can get any PID valve off the shelf for your use.You need to implement PID control in your software/controllar for this.Moreover PI might be sufficient for your application

Randy Copland

Evaporator temperature is controlled by by controlling evaporator pressure. Therefore what you are looking for is a modulating back-pressure regulator. By far the most commonly used valve/motor combination is an "A4AM" regulator made by Refrigerating Specialties or Hansen with a Honeywell M7284 mod-motor with a 4-20mA input.

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I was browsing the internet and hit your site. I am a design engineer and have developed refrigeration controller for many companies. Last was one low cost Z-80 based temperature/humidity/light control. All low-cost and user friendly. Temperature control within 0.1C deviation. On/off control close to PID output. This was developed for environmental control businesses.

Should you need more information or like to contact me, please let me know.


Respected Sir,

I would like to have more information on PID refrigeration system.

Some basic information on single stage and dual stage refrigeration is also requested.


We use A4Am modulating valve with standard BPR, we control this with a computer system that has PID loop controls, but i know Allen Bradley makes a small controller that offers all that and more for under $200 (peco controller) easy to program and easy to install......