Coolroom issue

[acura]

I have a coolroom that is running off a mechanical tstat Ranco . The Evap fans are set to cutout with tstat and pump down system is what seems to be the setup . Access is an issue to check system setup , Now the Evap is fully iced up i want to add a digital controller to control anti cycle and defrost but this is a SHELL refinery site and its a major ISSUE to alter any wiring and gain access to run wiring so i dont want to go near that option . Can any1 suggest a quality timer to wire into the condenser its just a small kirby condenser . I think this will solve my issue and just replace the thermostat and setup correctly to prevent icing as the refrigeration system seems to be working well . Im in australia so a timer from a major electrical company is useful . Thanks for any help

[G Cook]

How about allowing evap fans to continue running when condensing unit has cut out. This should help to reduce ice build up on the coil.

[Sandro Baptista]

good point

[Magoo]

As per previous suggestion, keep fans running in off cycle and get an air defrost of coil. I have a preference to use LP switch to cycle compressor so as to ensure a clear coil, rather than stat and pump down. The plus side is if coil ices up before design temp., due to door open etc., the system will stop and defrost when required as opposed to stat forcing it to run on. Takes time to set up LP settings but system will be bullet proof.