Not pulling below 26 in/HG - Does system need to be charged after replacing Drier?

[Cornbinder89]

Yes, oil type will effect the sealing of the pump. Oil is used not only to lube the pump but to make the seal as well.

[Cusser]

1. Yes, try the flush with vacuum oil; not so dissimilar than "flushing" R134a oil out of a new compressor to use with R-12 type oil.

2. I would see what vacuum you can achieve with just the service gauge fittings capped off. That would be the most one could expect with the service gauge connected to your system.

3. I think your new drier would be OK, it's closed to the atmosphere. At my work in the lab, we had desiccant cartridges which were see-through and some of the desiccant pellets were dyed with an indicator which would alert the operator to change the desiccant pellets. Pellets sitting in an opened cartridge (open to the air) lasted WAY longer before turning color due to moisture than a system using air pulled or pushed through similar cartridges. I'm talking like 100 times more air flow compared to a cartridge just sitting....

[Ac noob]

ok i will try and flush some correct fliud through it. Will this effect the pumps ability to pull down to deep vacuum?
Also will the drier/receiver be ok? i closed the system up immediately and pulled down to 25in/HG. - I have not charged system yet.

[Cornbinder89]

Not sure your going to be successful in getting all that compressor oil out of the vacuum pump. Might try getting a lot of vacuum pump oil, drain the compressor oil out, and re fill with vacuum pump oil and run for a while, drain and do it again.
I don't know if that will work or not, I would not put any "flushing agent" into the vacuum pump, nor would I try anything other than vacuum pump oil.

[Cornbinder89]

Wrong oil! vacuum pumps take vacuum pump oil, not compressor oil!
Mastercool Inc., Manufacturer of Air Conditioning, Refrigeration, Service Tools and Equipment

[Ac noob]

Hi All,
I am trying to charge the system on my car,
After 2hours the vac pump is only pulling down to about 26 in/HG, I disconnected the gauge hoses from the car and let the pump run and it still did not pull down any further.
I hooked the gauges back up with the taps off and after 24 hours it did not loose the vacuum.
The vac pump is brand new but is only a cheap 1 Stage 4cfm Pump, I filled it with Kinchrome Compressor oil (ISO100 SAE30).

Also, I replaced the drier/receiver and immediately closed the system back up and vacc'd it down. Will the drier still be ok?

Thanks!