AC question for Allen in NE

3 cyl · Jun 15, 2009

Allen,
I need to top off the freon in my tractor's AC system. I've borrowed a set of gagues. At what pressure on the high side should I stop adding freon?
Thanks
3

Coloken · Jun 15, 2009

Until Allan comes in here with the real scoop....high side has nothing to do with charging. Go by the low side ptessure.
KennyP

Allan in NE · Jun 15, 2009

My Colorado bud is right; the gauges don't give you an indication of level. Rather, just what is going on with the system.

You didn't say what kind of a system you're working on, but here's a trick an old phart up in North Dakota taught me.

If you can easily reach that receiver, when it is too cold to comfortably hold yer hand on it, yer full.

Otherwise, you can "weigh it in" or watch the temp at the outlets. When it gets down around 38-42, you're awfully darned close.

If you're working on a R-12 system, watch the receiver sightglass, when the bubbles stop flowing, stop the fill.

Allan

Kruse · Jun 15, 2009

Your comment of:

"If you're working on a R-12 system, watch the receiver sightglass, when the bubbles stop flowing, stop the fill" is fine if it has a sight glass. A lot of later R12 systems did not.

MPK · Jun 15, 2009

You should charge them on the low side which are the larger lines.

3 cyl · Jun 17, 2009

Thanks for your help everybody. Sorry for the mis-spell Allan.
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AC question for Allen in NE

3 cyl

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Coloken

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Allan in NE

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Kruse

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MPK

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