Plumbers: Inline pressure balance valves?? Questions?

[LD1]

Well, been doing some more research and called a few places today. I dont think the inline will work. I had the wrong line of thinking. I think:confused2:

In the basement, I have a hot and cold going up into the wall. From there, up inside the wall where i cannot see, is where it tees off for the sink and toilet.

If I put the balance valve in the basement, the outlet side of that valve is hooked to the sink, toilet, AND shower. The way the balance valve works is if there is a pressure difference on the inlet, it compensates.

IE: if running shower, my water pressures are both 60psi, then it outlets 60psi. If it sees a drop on the cold inlet to 40psi (someone flushed a toilet), it reduces hot down to 40 psi as well instead of leaving it at 60 psi and making the shower hotter. Well...even if someone flushes a toilet on the OUTLET side of the PBV....it still causes the same pressure drop on the inlet side right.....so all is good. or so i though.

What I wasnt accounting for was flow. While its true that a pressure drop AFTER the valve also means a pressure drop BEFORE the valve, and thus the valve will compensate.....its all about flow. IF I have my shower set to a temp that I like, and both lines are 60PSI......the temp is gonna be the same even if both lines coming out of the mixer drop to 40psi......UNLESS.......the pressure drop was caused after the mixer. Because now the 40psi out of the balance valve....that flow is being split between the shower and the toilet. So while pressure on hot and cold are still the same at the balance valve.......all that water going to the toilet to fill it, is water NOT coming out of the shower head and causing the shower to still get hot.

My concern, even with overly large beauty rings on the front, is just not having enough room to get in there and solder fittings on.

What I am looking into now, is the level of difficulty of removing the stand up shower, or at least just the part covering the fixtures. IF that will grant me access, that will take care of that shower. Then I would have no problem cutting a hole in my master bedroom closet to do the other shower head.

 

[the old grind]

I don't think you want to sweat copper through a one-piece unless you have a LOT of practice doing so in tight quarters. (we pre-assemble our stubs for builds that aren't drywalled yet) Good that you have 3/4" lines, as 1/2" shouldn't serve more than one fixture (code here for many yrs), but IMO most add-on valves are better at moderating surges than balancing H/C.

I might just risk the labor and ugliness of patching the closet wall and install a new shower valve with anti-scald protection and forget guessing whether a balance valve(s) is placed properly in the system. Nice to have access from below, but remember the guy who lost a quarter? He was looking for it two houses away because the light was brighter under the streetlight.

I had an 'blender' (check valve between hot & cold) on a 'closet' (our term) that mixed-in hot water to keep the tank from sweating. Once it stuck open you would get a brief rush of hot water in sink or tub from the cold valve as it back-fed from the stool. The house had municipal water of high quality, but something had scaled up within the valve and it stuck open. Anti-scald shower valves (most codes, now) have rendered such 'patches' obsolete, anyway.

Delta shower valves (they don't make a 3-handle, btw) can be serviced (cartridges/o'rings) and the temp adjusted by removing the handle and trim ring, once installed, so there's no fiddling, 'flow chart' confusion, or trial and error with the install. The type also moderates the difference in HW temp going from cut-on to cut-off, not just expect balancing pressure to attain a constant 'blended' temp.

IMHO, there is no box to 'think out of' here. I wouldn't overengineer this and would avoid gymnastics that might risk damaging the 1-pc S/T insert. t o g (now maint. supt, B___h Plumbing)

 

[teejk]

I don't think you want to sweat copper through a one-piece unless you have a LOT of practice doing so in tight quarters. (we pre-assemble our stubs for builds that aren't drywalled yet) Good that you have 3/4" lines, as 1/2" shouldn't serve more than one fixture (code here for many yrs), but IMO most add-on valves are better at moderating surges than balancing H/C.

I might just risk the labor and ugliness of patching the closet wall and install a new shower valve with anti-scald protection and forget guessing whether a balance valve(s) is placed properly in the system. Nice to have access from below, but remember the guy who lost a quarter? He was looking for it two houses away because the light was brighter under the streetlight.

I had an 'blender' (check valve between hot & cold) on a 'closet' (our term) that mixed-in hot water to keep the tank from sweating. Once it stuck open you would get a brief rush of hot water in sink or tub from the cold valve as it back-fed from the stool. The house had municipal water of high quality, but something had scaled up within the valve and it stuck open. Anti-scald shower valves (most codes, now) have rendered such 'patches' obsolete, anyway.

Delta shower valves (they don't make a 3-handle, btw) can be serviced (cartridges/o'rings) and the temp adjusted by removing the handle and trim ring, once installed, so there's no fiddling, 'flow chart' confusion, or trial and error with the install. The type also moderates the difference in HW temp going from cut-on to cut-off, not just expect balancing pressure to attain a constant 'blended' temp.

IMHO, there is no box to 'think out of' here. I wouldn't overengineer this and would avoid gymnastics that might risk damaging the 1-pc S/T insert. t o g (now maint. supt, B___h Plumbing)

Excellent advice on many points, not the least of which is how torches and acrylic surrounds/tubs are a bad combination. When I installed the tub in this house my plumber friend warned me about that. So I resorted to the Shark-bites" (leary about using them behind a closed wall because while they are a very good product, nobody is quite sure yet for how long). I built the base for the tub and was able to incorporate a removable panel that looks like it is part of the base but very close inspection will reveal the screws. As for code, I think it now says that any fixture will be supplied with 3/4" and the only permissible "Tees" to 1/2" would be to a toilet or water fountain. I could be wrong on that but that's how my plumber friend did it here and at my MIL's house when we stripped the rotten copper in favor of PEX.

 

[LD1]

I might just risk the labor and ugliness of patching the closet wall and install a new shower valve with anti-scald protection and forget guessing whether a balance valve(s) is placed properly in the system. Nice to have access from below, but remember the guy who lost a quarter? He was looking for it two houses away because the light was brighter under the streetlight.

It is done and thats what I did.

I removed the wall section of the stand-up shower to access that plumbing.

Cut a ~12x12 hole in the wall of the master closet to access the other bath plumbing.

Went to lowes and bought a couple moen faucets and a handfull of pex fittings. Sweated copper to pex adapters to the existing lines, and it was all down hill from there.