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Tankless piping 101...

TimcoTimco Member Posts: 2,814
Installed a Quietside combo a couple months back, great machine, but.....

1...Kicks on with toilet flushes. Just starts. Will a check valve stop this? Best type, placement?

2...Cold sammich. Toilet flushes kill the hot water and it has to restart. No good. Going to install a 6-gal WH to defeat the sammich. Any way to do that tiny tank solar?

Install pics later. Starting heating pipes today. Thanks!

Working on steam and hot-water systems isn't rocket's actually much harder.


  • IronmanIronman Member Posts: 3,436
    Cheap Shower Diverters

    Cheap diverters, like those sold at the big box store, have inferior checks in them that will let enough water bypass through and cause the tankless to fire.

    Try closing the supply lines to the diverters and see if that corrects the problem. If so, the diverter(s) need rebuilding or replacing.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • TimcoTimco Member Posts: 2,814

    Do you mean the balancing valve? We have a shower only downstairs and a 2-handle style clawfoot upstairs. If everything is off, then a toilet gets flushed, it kicks on the tankless but not long enough to fire it.

    I do have a new shower fixture to install as part of this entire upgrade. Old one was living on iron pipes for 8 years now. Wanted all new and am installing a bypass and iso valves to have a hand sprayer for a dog washer. Just ran all new copper, entire house, added x-tank for DHW.
    Working on steam and hot-water systems isn't rocket's actually much harder.
  • billbill Member Posts: 429
    edited September 2013
    i don't know...

    The first thing Ithought of was a toilet mixing valve?

    But more importantly, just what is a cold sammich? Or a hot one ? And why would you want to defeat said sammich?
  • TimcoTimco Member Posts: 2,814
    OH, NO!!! THE SAMMICH!!!!

    When it's been running, and making hot water, if you turn off said hot water for EVEN A SECOND, you get a 'sammich' of hot left in the pipe, cold from start up of tankless, then hot again when it picks back up. Very annoying in certain situations, and when the front loader washer calls it does not really get hot water since it uses pulses of water to reach it's weight.

    This business will get out of control. It will get out of control and we'll be lucky to live through it.......
    Working on steam and hot-water systems isn't rocket's actually much harder.
  • Le JohnLe John Member Posts: 50

    Are these reliable boilers?
  • TimcoTimco Member Posts: 2,814

    So far (2 months or so) it's made hot water every time, but I'm piping the boiler pipes now. I need to figure out how best to control a mod-con with a tN-4 where the reset is in the control, not the boiler. Boiler just has a couple leads and that's it.

    Very quite and compact. Pics in an hour or so when I'm done for tonight.
    Working on steam and hot-water systems isn't rocket's actually much harder.
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