Quote:
Originally Posted by bob deluke
A couple simple things to check with the contractor. Is the vacuum pump a minimum 3-5 CFM capacity? Is pump oil clean, should be changed after each use as contaminates, moisture are captured in the oil. Does pump pull below 500 microns when “blocked” off? Does the tech know triple sweep, double evacuation procedure? Did they purge the line set with nitrogen before brazing to prevent oxidation? Looks like they used foscopper brazing solder on the lines, not silver solder or silfos or stabrite. You should talk to the tech intelligently before he starts to work as rwest suggests, so he knows you’re pretty well versed as to what’s happening with the system. Good luck, hopefully the problem will be resolved.
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Bob, thanks for the interest and comments.
FYI - When the system was first installed they pressure tested with nitrogen and vacuumed the system. This is where we hit a snag. I read the Mitsubishi manual that describes the vacuum process and specs. Their equipment initially was not capable because it was worn out and needed maintenance. I figured all this out and they finally showed up with much better equipment and pulled an "okay" vacuum.
So, I feel justified in being skeptical and wanting to watch closely to what they might do. I understand it is not comfortable to have someone watching over you when working. The bottom line is at this point - when someone makes a big change (very open to don't be near us) without explanation - it makes me feel they are untrustworthy.