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Old 05-14-2007, 11:42 AM
gmercoleza gmercoleza is offline
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Join Date: Sep 2004
Location: DFW / Collin County Texas
Posts: 1,882
Quote:
Originally Posted by brewtoo View Post
I've always thought that using the sight glass was perfectly adequate. Else why would it be there.

What the system wants is a steady stream of liquid refrigerant coming from the drier, thru the sight glass to the evaporator. The sight glass gives you that info.

Yes, if you are wildly overcharged or undercharged the sight glass can be misleading.

The reason systems with accumulators don't have sight glasses is because there are always some bubbles in those systems. Hence, the sight glass would be misleading in that case and the gauges would be the only way to go.
I have on 3 or 4 occasions "thought" that system charge was correct using the indications from the sight glass, then shortly thereafter discovered that they were way off after hooking up my manifold gauges. In researching both at this site and elsewhere, I have found that I am not alone, and most techs now say the PROPER way to charge is by weight. This is now the way I do it - put the correct weight in, and forget the rest. I still of course do this through the gauges.
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08 W251 R350
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86 W126 560SEL
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85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280
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