Instant On HW and Shut Off Valves

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by joe in queens, Jan 5, 2007.

  1. joe in queens

    joe in queens New Member

    Messages:
    36
    If you're piping a water system from scratch, and whole house instant-on hot water is in your plans - with a Grundfos pump and all at the source - how do you handle the issue of shut-off valves at each fixture since the system is one giant loop?

    The code compliant way would seem to be a T, with the line going from the T to the fixture having the shut-off installed in between - and accessible of course. However, if this line runs far from the HW loop - which will likely be the case in some spots - it kind of defeats the purpose; you'll end up waiting for the HW to run through the line. :mad:

    The most effective and efficient way would seem to be a giant HW loop, with the loop running as close to the fixture as possible. However, in this scenario the loops would end-up behind the wall - say a shower valve, kitchen sink, and what not - with no access to a shut off, so you'd end up with a supply line and return line that are accessible in a basement or crawl space. So in this case the only alternative would be to install the shut-off, but this would kill everything downstream of the shut-off. Might as well not even install HW shut-offs, and just close the shut-off at the HW source. :confused:

    I've gotten conflicting answers from my friends in the plumbing trade. Some say I must go with the first scenario - code is code, and can't be sacrificed in favor of comfort and efficiency. Others say concealed plumbing isn't subject to shut-off requirements, shuts offs at fixture units like undercabinet sinks are sufficient, but what about things like washing machines and dishwashing equipment, not to mention outside hot-water frost-free hose bibs? My friend who'll be filing the job (job is in NYC) where I'll be doing the work under, says just make sure there's a shut-off there for the inspector to see, doesn't matter if it's after T or kills the whole loop as long as the water can be shut-off. And still other say for HW only a shut off at the HW heater or boiler is necessary and not to waste my money, individual "hard" shut-offs are not needed. :confused:

    Obviously, I don't want the embarassement of being red-tagged with a friends license, not to mention having to rip expensive copper out... so I am all ears and eyes! :eek:

    Thanks so much in advance folks!
  2. markts30

    markts30 Commercial Plumber

    Messages:
    630
    Location:
    Phoenix, AZ
    We usually don't have shutoffs on the individual drops in the walls - the angle stops are sufficient here...
    For the drops to the frost free hose bibbs, I am assuming you wish to be able to shut the water off inside after closing them off for the winter...
    In this case, I would put an additional valve on the drop in the basement with an access panel in the wall (if a finished basement.)
    For our hot water system loops, usually we valve all the sub outs by the heater (hot, cold and return hot and have an expansion tank on the hot line between the tank and the valve...

    Attached Files:

  3. Phil H2

    Phil H2 New Member

    Messages:
    125
    Location:
    Tujunga, CA
    Joe,
    I think you are splitting hairs on efficiency. You have to branch to the fixture no matter what. For instance, a sink faucet typically has a flexible supply line that goes to a stop (valve). This makes it easier to install (or remove). The amount of water and the time to go through the flexie are negligible. If you are concerned, just use the shortest flexies practical.

    Washing machines must have a valve; the hoses attach to the valve. Dishwashers are typically next to sinks and the valve is under the sink. Again, the dishwasher is attached to a hose/tubing - just place a valve on the other end of the hose.

    Your local code will determine what must have a valve. IIRC, the IPC requires a shut of for every individual sillcock or hose bib. A branch to the shower will not cause much of a wait. At 1 gpm, water will travel about 1-1/4 ft per second in 1/2" copper.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,647
    Location:
    Cave Creek, Arizona
    loop

    The shutoff for the fixture go outside the wall. The return loop connects inside the wall without any shut off on it, except where it connects back to the water heater.
  5. joe in queens

    joe in queens New Member

    Messages:
    36
    Thanks for the replies folks...

    I guess I don't want to run afoul of IRC 2903.9.3 or UPC 605.5 - everything except tubs & showers - as well as our local NYC codes.

    The whole question comes down to what the intent of the code is... because a shut-off somewhere in the loop will shut everything downstream off on an instant HW loop. Does the code care if everything else get's shut-off downstream, or is the code only concerned with having the ability to shut-off a given fixture for service? In some cases the a shut-off in the single supply line off the HW loop will be a bit too far, then you go through the little bit of flexi too.

    There's also the question of whether the angle, chrome shut-off valves typically found for sinks are sufficient for the shut-off requirement. Most jobs I've seen here in the NYC area have ball valves downstream of these valves as well, so two shut-offs.

    Forget about checking with the AHJ on this one... this is NYC. Assuming you can even get through to the right person, if you ask the same question of 3 different inspectors you'll probably end-up with 13 different answers. And the person you'll be speaking with surely won't be anyone who'll actually do inspections.

    Obviously, extra shut-offs can't hurt and is not a code violation (unless you're being stupid with one every foot or something), my concern is making sure they're in the right places, hence the code "intent" question.

    Thanks for the great replies and insight!
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