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DeadEye
14-08-2010, 01:42 AM
When recovering from a MVAC something in either the accumlator or the evaporator makes a load pop followed by a wooooosh (like the sound of a trucks air brakes) and the pressure jumps about 15 psi.

It happens at low pressure 10 to 29 in Hg vacuum and sometimes it happens twice.

Where release of refrigerant gas from ?
nike123
14-08-2010, 07:52 AM
You say recovering at 10 in vacuum.
Don't you suppose to do vacuum drying and not recovering with that low pressure? Maybe there is your answer. Recovering equipment is not designed for vacuum drying.
frank
14-08-2010, 08:31 AM
It's more than likely the refrigerant releasing from the oil in the accumulator or compressor sump
DeadEye
17-08-2010, 03:00 PM
You say recovering at 10 in vacuum.
Don't you suppose to do vacuum drying and not recovering with that low pressure? Maybe there is your answer. Recovering equipment is not designed for vacuum drying.

The recovery machine pulls down to 10 in vacuum before automatic shut off. Yes I could shut it off sooner as regulations dont require you to recover to that level on the small MVAC systems.
Most often this happens after recovery while using a standard vacuum pump and close to a deep vacuum 29in hg.

Thank you for the input. D.E.
DeadEye
17-08-2010, 03:02 PM
It's more than likely the refrigerant releasing from the oil in the accumulator or compressor sump
This is what I figured it was.

Thank You.:D
nike123
17-08-2010, 03:19 PM
How many CFM is your pump?
NH3LVR
18-08-2010, 02:55 AM
I had this happen once on an old Roterex compressor on on board a fishing tender. It was the mechanical shaft seal. I looked in the book and it said not to pull over i5 inches of vacuum.
dave hammo
18-08-2010, 10:33 AM
the 'pop' may not be caused by refrigerant perhaps air sucked into system from faulty fitting maybe collapse of diaphram on pressure control?
DeadEye
18-08-2010, 08:24 PM
How many CFM is your pump?
rfo
5 CFM two stage Refco.
DeadEye
18-08-2010, 08:31 PM
the 'pop' may not be caused by refrigerant perhaps air sucked into system from faulty fitting maybe collapse of diaphram on pressure control?


Dont think so as the pressure goes to the + when this happens.