AC equipment
#16
Chronic Tool Dropper
Lifetime Rennlist
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Lifetime Rennlist
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If you are reading PS I for vacuum, you have the wrong gauges or your pump sucks poorly. (Had to think about that a bit...). My industrial/lab pump does everything but bend the needle over the stop pin on my Robinaire gauge set. So if your anywhere near sea level, try a more serious vacuum gauge to verify that you have enough suction to boil out all the moisture in your system. Just a little bit of air will trash the system performance, and a little moisture loose in the system will hurt the expansion valve and eventually perforate the evaporator. A few PS I of partial air pressure in the system will easily cost you twenty hot-day degrees of cooling at the evaporator. I've listened to more than a few DIY experts who report awesome vent temps as low as fifty degrees, don't need no stinkin' vacuum pump! Just sweep the system. They are way wrong.
#18
So we moved on to electronic or digital gauges, however here to, depending upon the voltage of the battery, we notice variations in measurements but not to the degree as you find with less expensive analog gauges. On occasion we use 2 digital gauges on the same manifold set, both set to read in microns vs. inches of mercury, and the 2 never present the same reading; one of which needs to be 'zero'd' out before each use (add the 2 and divide the sum... lol).
And I'm sure if we sent the 2 digital units to different calibration labs we get different findings.
So if you are going to make A/C a full time occupation then invest in a good quality digital gauge that offers both micron and inches of mercury readings.
(I believe Robin Air and Tif are just a few sources you can explore).