Micron creep

[nlovas]

First time I've ever used a micron guage. 410a split system. I pulled vacuum and here are my results:
Pump shut off at 144 microns.
+1 hour: 275 microns (131 increase).
+1 hour: 339 microns (62 increase).
+1-3/4hour:413 microns (76 increase).
So in 3-3/4 hours 269 micron increase.

Is this amount of creep normal? Should this creep have stopped at some point?

Also, I was thinking of leaving the vacuum pump on overnight but it's getting cold at night (34F low). What is too cold for leaving a pump on?

Thanks and have a great day!

[seatonheating]

First time I've ever used a micron guage. 410a split system. I pulled vacuum and here are my results:
Pump shut off at 144 microns.
+1 hour: 275 microns (131 increase).
+1 hour: 339 microns (62 increase).
+1-3/4hour:413 microns (76 increase).
So in 3-3/4 hours 269 micron increase.

How much of this creep is from micro leaks? Is this amount of creep normal?

Also, I was thinking of leaving the vacuum pump on overnight but it's getting cold at night (34F low). What is too cold for leaving a pump on?

Thanks and have a great day!

Sounds like a good vacuum and I applaud you for doing it right!!!


Outside pressure differences, improper hoses and/or connections could be the reason for this creep. Internally you have a dry and clean system. Charge that sucker up.

[I_bend_metal]

At 144 on your initial pull.....you're good....

A small creep is fine....

If you would have gone from, say, 144 to 500 in a matter of a few minutes,
I would say you have a problem.....

For a residential, split system, it shouldn't be necessary to leave a pump
running over night...

With the proper tools and set ups, a solid, 200 micron (or lower) vacuum
can be pulled in 20 minutes....

Great job using the micron gauge....glad to see more guys taking pride in
their work!

[nlovas]

Thank you. You've given me important information I need to help me do a good job.