Need advice for head pressure controls

[svardekar]

What factors should I take into consideration while buying a head pressure control for refrigeration, food storage rooms, and agriculture purposes?

[scarey8]

This is a pretty broad question as is, what refrigerant are you running, what is your box design temperature and TD?  What do you have for a condenser? Air sourced or fluid?  Does your system have a receiver?

Depending on product in the box, you would be running somewhere between 32-38 degrees F.  All TX valves are sized based on 90 degree F liquid, so depending on your refrigerant you would select a headmaster/ LAC or ORO valve to maintain that saturation pressure to your evaporator.  This is all assuming you have a receiver on your system.  If there is no receiver, your option would be fan cycling heat pressure control.