Vacuum pump

I have a 1995 chevy WT1500 truck. It needs a compressor and accumulator. I flushed the system out and sealed the lines going to the compressor. Used a robinair vacuum pump 15310 to pull a vacuum to see if I had any leaks before putting in a new compressor and accumulator. Ran for an hour but gauges only went down to 5 inches. Closed low side valve off. Gauge held at 5 inches. Discharged system through high side port and it went to zero. The system seems to be tight. Is the vacuum pump just a piece of crap? I got it yesterday.

Reply to
Ringer
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Vacuum is measured in microns, not inches.

Did you get the special vacuum pump oil, and put that in according to the directions? Robinair is a good brand. I have one, and it works well.

Christopher A. Young Learn more about Jesus

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Reply to
Stormin Mormon

Reply to
Ringer

Reply to
Ringer

I don't remember the numbers, but to read a "good" vacuum, you need a micron gage. (sold separately). A manifold gage is far too crude, to know if you're getting a good vacuum.

A crude example, would be using the odometer on your car, to measure the framing to build a house. You just can't get precise enough to be useful.

Still, it should have gone lower than 5 inches of mercury.

Christopher A. Young Learn more about Jesus

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Reply to
Stormin Mormon

If memory serves, a micron is 1/1,000,000 of a meter. A full vacuum is whatever the mercury is, on the barometer. Mixing metric and English, here. It may be tough to follow.

A "deep vacuum" is something like 29.96 inches of mercury. (a meter being about 39 inches). You can get to 29 or 30 inches on your manifold gage. But how do you know if it's 29.80 or 29.91, or 29.96? You can't, on manifold gages.

With a micron gage, you can tell if it's 1,000 microns away from deep space vacuum, down to reading of 100 or 50 microns on the scale. For HVAC work,

400 microns is good. Deeper vacuum than that, and it's a bit rough on the equipment and the system oil.

Christopher A. Young Learn more about Jesus

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Reply to
Stormin Mormon

That said.... if your pump slammed the manifold gages to 30 on the scale, there is a good chance you got most of the air and moisture out, and you're read to charge the system.

Christopher A. Young Learn more about Jesus

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Reply to
Stormin Mormon

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