View Full Version : Condenser fan/pump sequencer in NH3 plant

24-04-2013, 05:02 PM
Good day,

I am looking for a new option to control my condenser fans and pumps. Due to upgrades over the years, I have a condenser controlled by pressure switches, another controlled by the old system PLC and a third simply in manual. I want to get everything on the same page with perhaps some versatility to alter the start/stop sequence as needed.

I need some sort of multi-channel sequenceer that can handle turning three pumps and three fan sections on and off based on input from a pressure switch or a transducer or whatever. My controls are such that I cannot make changes to the PLC programming or I would simply expand the logic out to handle all of the condensers.

What do you all use? A small stand-alone unit, either mechanical or electronic, that will get my whole roof sequenced would be ideal.


24-04-2013, 10:02 PM
Hi. Depending on available PLC inputs / outputs, get an Automation contractor to modify the logic.. Else, if the fans are fixed speed, perhaps an electronic step controller. Otherwise, modern VSD's are usually capable of regulating from a range of onboard parameters.