Hi all, having thought this one to near death I'm hoping some have thoughts on possible leaks in brazed plate heat exchangers. We have a lazer lab that has a 10 ton R-22 Manuerop hermetic that circulates chilled water (approx. 80 gallons) through a loop to other heat exhangers that cool the lazer machines. The chilled water loop and the lazers are totally separated. Yet we found an oily residue floating in the top of chilled water barrel.

The compressor has failed by a somewhat quick burnout. The oil was drained from the crancase and about a tablespoon of water was found. The liquid line dryer had plugged and when cut open about another tablespoon of water was found. It was an Emerson dryer and therefore not a molded core dryer. The water cooled condenser and the BP evaporator have been isolated and pressure tested for 3 days with no pressure loss whatsoever. The BP evaporator was subjected to a vacuum test with a micron gauge and held to 1000 microns ( we were pressed for time late Friday afternoon).

The 3 phase grounded compressor burnout can be traced to a faulty contacter but it's the moisture found I'm having the problem with. This compressor was changed out 2 months ago by a fellow that is no longer with us, so he's not around for me to ask questions.

Oh btw, the CW flow switch failed closed. The manual reset freezestat was not tripped and was set at 40F. It uses a Ranco 1 stage electronic thermostat. The CW pump runs 24/7 and chilled water setpoint is 50F off and 60F on. Pump down control is set at 5psi.


I suppose I could attribute the moisture to a real sloppy compressor changeout. Or is it possible for a brazed plate evaporater to pop a leak and then close back up?



thoughts?