Hi Guys don’t know if you are able to help me at all, I have built a three stage cascade which is running R507a in the first stage then R1150 in the second stage and R14 in the third stage compressor.
The compressors are 1st stage 24000BTU, second stage 17000BTU, third stage 17000BTU.
Oil Sep on both the second and third stage so there should be no oil getting past.
The problem I am having is the third stage is pulling a very deep vacuum of 20” with liquid line pressures of 15 bar when running, this is with a very short cap tube of 2.3mtrs of 0.036 cap tube, I have checked to make sure there are no blockages and have replaced cap tube many times now also with new filter driers, the third stage has always been vacuumed to 250 microns so there should be no moisture in the system at all, i just can not understand why this is happerning or what is going on.
If anyone can help I would be most grateful as I am pulling my hair out at the moment and cannot see why I have this problem.
When the system was first run up it ran fine for one day then the problem started with this deep vacuum
Pictures of the build