Standard Piping Procedures for Supermarket Cases???
pretty new to the supermarket industry as I've spent my whole apprenticeship in HVAC thus far, so I thought I would get some feedback regarding proper piping practice that any of you use who may be in the industry. As any of you in HVAC know, it is pretty common practice now-a-days to purge while brazing on all new systems- especially ones that will have POE in them due to POE's scrubbing ability (not to mention the acid formation from the carbon residual combining with all that nice new gas and oil). In addition to purging, my experience in HVAC, as well as everything I've been taught and have learned about refrigeration thus far has taught me to be as vigilant as an emergency room doctor with respect to keeping systems free from contaminants and moisture.
Well WELCOME TO SUPERMARKETS, LOL!!! SO far I have had a jaw dropped to the floor and eyes popping out of my head on a daily basis due to the difference in tolerance, for lack of a better term. When I asked why such measures were not taken to prevent contamination from moisture and other non-condensibles, I was told that regular supermarket maintenance includes regular filter changes, that the systems are just so big that they are less 'delicate' than HVAC systems, and that due to time constraints, the focus is more heavily placed on "get it in, and guarantee no leaks!"
Now, all HVAC guys out there can say what they will about proper installation procedures, but this info has come from A LOT of guys with A LOT of years in the grocery store industry, and there are not TONS of service calls and premature component breakdowns. The other thing that totally shocked me is how frequent there is no pressure test done and welds just HAVE to be good enough......that's one I'm still on the fence about.
Anyways, I just wanted to get a good thread going on this. So whadda you all think?
I use nitrogen on small things. Personally have never worked with a company that did purging on a regular basis. We use nitrogen when doing medgas lines (duh!) You want to talk about being being diligent when you're piping!
I've done over a dozen supermarkets and never used nitrogen. It's extremely time consuming, expensive and you run into other problems (pressure build ups causing the lovely last second hole in your joint right as it's about to set).
Is it the right thing to do? Yes. You're never going to be able to 100% purge everything. Yes the odd screen gets plugged at the tx in a case case but it's not hard to pump down systems and clean them. We have always done liquid, suction, oil filter and oil changes in any renovation. You can try to be as diligent as you want but it's hard to keep copper filings and 100% of the contaminants out of your piping. Heck one of the guys found a piece of tubing in one of the suction filters recently.
Pressure testing? Refrigerant is expensive. Anyone who doesn't pressure test is looking for a lot of trouble. Pressure testing is absolutely essential.
Lifetime supermarket guy, here.
That IS the prevailing attitude. Get it in fast.
I much prefer to see purging done as it does make a cleaner job and it doesn't take that much more time.
Some customers are starting to mandate it and will go in and cut out joints to inspect.
The chain I worked for 25 years ago had that in the installation specs. We had the right to cut out and inspect two randomly selected joints per system. If an inspection indicated N2 had not been used during brazing, then the entire system must be repiped. (A full repipe never happened, to my knowledge.)
Originally Posted by jpsmith1cm
It's good to hear the stores getting serious about this again.