Parker Hanifin Flo-Con

[1buck]

Hello..sort of a newbie here.

Have a Kramer 62 HP low temp system with hot gas defrost capabilities (thermobank system). Freezer runs at -16 F and the system runs pretty smooth during normal operation. when put into defrost, the suction and discharge valve closes and the holdback valve slowly modulates the liquid into the bank and maintains for a few moments at 20 psig until it looses control for awhile until it regains control again. During that time quite a bit of liquid has accumulated in the accumulator. Once the valve recovers, the system defrosts within 10 minutes. Only problem is I don't think these compressors can take this much of flooding abuse before we loose a wrist-pin or valve plate.

I've moved the cap. from the outlet of the bank to the inlet for the holdback valve and lowered the discharge pressure control from 300 psig to 250. I'm just wondering with such a large system and short piping run that I might be building up too much head pressure during defrost that the flo-con can't respond fast enough. I can't explain the sudden increase in suction pressure for the life of me during defrost.

Have quite a bit of expierience with these systems over the last 20 years and have never seen anything like this before. I'm thinking to much of all the the possible scenerios that may be going on and it might be time to throw it out to this forum for possible solutions.

[weagle]

What refrigerant? And how is the discharge superheat? What temp is the suction line?