With my new job I am running in to some different types of systems I am not overly familiar with and could use some help understanding what is normal operation for some of them.
I am currently working on a fair share of environmental rooms that use hot gas bypass and digital controllers to keep the room within a few 10ths of a degree for experiments requiring precise temperature stability.
These use central chilled water for condenser cooling and run 24/7 just switching a liquid and hot gas solenoid back and forth.
Usually they are R-22 or R-12 and sometimes R-416
There are a couple of components that I am having a hard time adjusting and understanding.
One of them is a CPR or crankcase pressure regulator and is supposed to be set by compressor amp draw.
What is its purpose?
Also another component is the water regulator. I understand what this does opening and closing it allows more water or slower water movement around condenser coil and effects the high pre4ssure but I am not sure what a good pressure is.
I have been instructed that by taking the inlet water temp (Ours is usually around 45) that the outlet temp difference should be around a 20 F rise or 65 F.
They also have TXV valves and site glasses for charging.
I recently replaced the CPR in one unit and my superheat was very high over 30 but the room was 90 degrees.
When I came back in the morning it was frozen all the way back to the compressor. I recovered some refrigerant which caused bubbles to appear in the site glass but the frost went away.
Later that day I returned only to find the evap now starting to freeze.
It is a cold room set at 4 C and is keeping it steady at that but I need to understand more about this system and do something about the evap now freezing.
Any help would be greatly appreciated.