Working an a Mueller milk cooler again. It has two condensers, M#A51-HPF. 5HP copeland comp. with subcooling valve.(valve to maintain 10 degrees subcooling, with flooded evap.) Complaint is not cooling fast enough!
The milk was 50 degrees when I arrived. The cond. unit that is piped to I believe the side coil of the tank had these readings:60lbs suction, 180lbs liquid line, 12 degrees subcooling, 5 degrees superheat, 99 degrees discharge line temp.
The cond. unit piped to the bottom coil in the tank had these readings:60lbs suction, 210lbs liquid line, over 20 degrees subcooling, 1 degree superheat, 155 degree discharge line temp. 24 amps.
Ambient both units, 56 degrees. Only one fan operating on each unit, second fan on fan cycle switch.(on 250 lbs, off 200 lbs. 21 amps.
I covered the cond. coil to bring up the hi side pressure. on the first cond. both pressures came up and the hi side would fluctuate from 245 to 200 lbs., the second fan would not cycle on and the suction pressure held steady at 70 lbs. The sc would go to zero with the hi side pressure flucuation. Amp draw would go up also. along with discharge line temp.
That leads me to believe that that comp. is operating properly, except the low discharge line temp. and hi side fluctuation when cond. covered. Subcooling and superheat are within parameters as is the amp draw. Any ideas about what might be wrong with this unit? I am inclined to replace the comp? Should I recover the charge and see if I am low?
The other unit I also covered the coil and both pressures came up. Only the second fan cycled on this unit. Subcooling stayed above 20 degrees, amp draw came up and down with fan cycling. I am inclined to believe the subcooling valve is bad(only 2 years old). This unit had a leak on the suction service valve, which I fixed this afternoon, recovered 17 lbs 14 oz. Total charge 19.5 lbs.
So do I replace the subcooling valve? again! or is something else going on that I am missing?
I also took readings when the milk hit 45*, suction pressures lower of course but sc and sh not changed.
I will try to moniter this a while tonight if anyone has questions.
Don in MO