silver solder

[cctrol]

I work mostly in commercial refrigeration, I generally don't use anything except 15% silver. soft solder and hot gas defrost are not a good combination.

[condenseddave]

Originally posted by cctrol
I work mostly in commercial refrigeration, I generally don't use anything except 15% silver. soft solder and hot gas defrost are not a good combination.

Good practice, but I'm here to tell you, if your HG defrosts are anywhere near 450 degrees F, you've got bigger problems than what solder to use.

[cctrol]

Originally posted by condenseddave


Good practice, but I'm here to tell you, if your HG defrosts are anywhere near 450 degrees F, you've got bigger problems than what solder to use.

True, but expansion / contraction due to defrost temperature swings in piping, along with the pressure surges at defrost are reason enough for me to be wiser than I am frugal.

[frozensolid]

For some reason hot gas does not like 45s either.

[icemeister]

Piping for HG defrost is very susceptible to thermal expansion/contraction forces that result from the thermal changes going on.

Just imagine a two-pipe HG system (like all market HG systems) where a 200 ft suction line at minus something degrees suddenly gets hit with one hundred and something degree hot gas. The pipes have to move and the stress is greatest at the joints. 45 Deg ells are inherently weak and any good supermarket specification will prohibit them. Stab-ins and reducing bushings are no-nos too. A&P back in the old days required the proper reducing fitting at every reduction and branch. When's the last time you saw a 1 5/8 x 1 3/8 x 7/8 tee used on a job?

It's not uncommon to have a long run want to move 4-5 inches due to the thermal change. This is where I think the soft-solders like 95-5 and Sta-Brite lose it big time.......with the stress over time. Been there.....

[frozensolid]

I don't think I can ever remember seeing, or piping the required expansion loop.

[icemeister]

Do you mean the loop in the Hussmann install books? No, I never saw or did one like that either. Usually you have a 90 in the line and you have to allow that joint to move by moving the clamps way back.

[frozensolid]

I think it is in the Kysor/Warren book too.

We never clamped anything but our main suction risers, and liquid lines coming in to the house.

Our saddles were PVC gutter, cut in one foot pieces. We would drill two holes in the saddles to accept push pins. The kind in door car panels. The pins would straddle the unistrut so the saddle would not dislodge during expansion.

You don't know how many times, I have seen a plumber get busted, for having a PVC vent in the return air. The Inspectors never said a word about our saddles. Go figure.

[condenseddave]

Originally posted by icemeister
When's the last time you saw a 1 5/8 x 1 3/8 x 7/8 tee used on a job?

I've got a box of them, and a box of 1-3/8 x 1-1/8 x 5/8 in the shop. Covered in dust. Need any???

[condenseddave]

When I first started, we installed the expansion loops in a few stores. A few years later, I recall going on a call where one of them broke. That was the last I heard of them.

45's and street 45's are banned by every single chain that I've ever worked for. They are not just banned in refrigeration, but in the plumbing, and even the drains. (Including the walkins...)

[R12rules]

Originally posted by condenseddave
45's and street 45's are banned by every single chain that I've ever worked for. They are not just banned in refrigeration, but in the plumbing, and even the drains. (Including the walkins...)

Why?