Is it unreasonable to expect?
I have an r-22 DX evaporator that a technician has determined is leaky. He said he would pull down the refrigerant into the condenser to do the evaporator changeout.
1. Is it unreasonable to expect him to flow nitrogen while brazing the connections?
2. Is it also unreasonable to expect him to use a micron gauge rather than a compound gauge to hold a 500 micron level for 15 minutes to show the system is free of contaminants and somewhat reasonably free of significant leaks?
I know it would be best if it could be left overnight, but I can't afford the cost of another service call and am willing to live with less than ideal. I also realize that if he did a pull-down on the condenser it would not show that the condenser is faiirly leak free.
Thanks for your thoughts.
1. You must flow Nitrogen while brazing. Anything less is a "hack". There a video showing the effects of brazing without Nitrogen. Search for it to see for yourself what can happen!!
Originally Posted by Junkers
2. Being able to obtain and hold <500 microns is a must. The typical compound gauge won't accurately read that low. If I recall, 29.9 inches of mercury is a whopping 20,000 microns. You need special instrumentation to read this low. Anthing less is a "hack". (holding <500 microns overnight isn't necessary, one service call should be able to verify leak free repairs - no need to make compromises if you've picked out a good tech.)
There should also be an intermediate step between one and two. That step involves pressuring the system to >150 PSI of Nitrogen and spike it with a shot of refrigerant. Then he should use his sniffer and /or soap bubbles to verify his new connections/repairs. (testing under pressure and vacuum is a the best known method and demonstrates professional workmanlike standards).
Thanks for the middle step! Chalk one up for the good guys on the pro/hack scorecard.