Deep Vacuum Effects?

[Alan Shore]

Does anyone know what the possible effects a deep vacuum would have on a filter/dryer using a 100% molecular sieve XH11 desiccant? A Parker BF 163S-XF for 410A application.

Deep vacuum <30 microns.

Can it have a negative effect on a new dryer?

Since it is a molecular sieve can moisture be vaporized out of a contaminated dryer? I would never reuse a dryer but there have been times when I would like to know if a dryer that has been removed had any moisture in it so I would know if the system was dry before being opened. Pull a deep vacuum on the removed dryer and then add heat to see if it effects the vacuum? Would this give some indication if moisture was present?

[Brian_UK]

The drier would have absorbed moisture as soon as you took it out of the system.

The vacuum test on it would not prove much.

[casstrig]

Pulling a deep vacuum would have evaporated any moisture so no point heating it up.

[Alan Shore]

The used dryer would be cut out, not heated if it is welded in. Have also been using some with flare fittings.

The used dryer would be capped instantly upon removal.

The test would be the amount of time it takes to pull down to <30 microns as compared to an identical new dryer.

My goal would be to have some idea if the system had ever had much if any moisture.

Using an acid test on the original refrigerant is almost useless. The systems I am seeing have very little(if any) oil circulating with the refrigerant. No matter where you open the system outside of the service valves it is dry, no sign of ANY oil, looks like new, unused equip. And getting an oil sample out of the comp is not an option when there is no real reason to suspect an acid problem.

An idea of the moisture content of the removed dryer would just be for peace of mind.

Crazy idea?

[narkom]

">> Here's the application: Air conditioning systems contain a silica gel
>> canister in the refrigerant circuit to remove damaging moisture from the
>> refrigerant-oil mix.

I can't speak for the USA, but here many of the hermetic systems use
Molecular Sieve 4A driers, which have a much greater capacity ( 22% mass ),
and less volume is required. They are not able to be regenerated because
the required temperature to remove water ( 220C - 350C ) will not remove
the oil - and the heated oil degrades on the active surfaces and destroys
the ability to absorb water, and higher temperatures result in physical
breakdown of the sieve. Older systems used much larger silica gel driers."

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