Dear Friends

I think that we have discuss deeply the ammoniac hot gas defrost system for evaporators

The question is how to start the defrost timeless?

What signals should I set to start the defrosting no by time?

We know that a temperature sensor located in the coil (coldest zone) will end the defrost cycle. But how to start each cycle.
If there are 6 evaporator how will be the secuency?

I am dealing with a room at -28șC ,pumped ammoniac 4:1 , Evaporating at -33șC/Tc +35șC ,Total load 420kw
Appreciate you comments
Regards gwapa