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paul_91
paul_91 Member Posts: 62
in THE MAIN WALL
why would they use a check valve?

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  • paul_91
    paul_91 Member Posts: 62
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    therm-x-trol

    can anyone explain to me what a therm-x-trol tank is and when should i use one?
  • Michael Wilson
    Michael Wilson Member Posts: 46
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    Domestic Water use

    http://www.amtrol.com/pdf/MC8551 9003-038 06_07 TXT Mailer Home.pdf




    I've needed to install them when there is a check valve on the street side of the water meter... it keeps the relief valve from popping when the water heats up.

    Normally the water would expand and push back out of the water meter toward the street. With a check valve there, the water has no place to go but out of the relief valve




    I'm sure there are other uses or needs for them... I'm sure others will chime in :-D





    Mike
  • Michael Wilson
    Michael Wilson Member Posts: 46
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    cross contamination

    The check valve is to prevent cross contamination with the main water supply in the street.

    Here's an example:


    A far fetched situation mind you, but imagine you have one of those old can style Miracle Grow hose attachments on your garden hose and you're out back feeding your lawn...

    There is a house fire in your neighborhood and the fire department hooks up to the fire hydrant right in front of your house. The pressure drop on the main could potentially suck the water right out of your house system. If you aren't using a new style hose bib with a vacuum breaker, that lawn fertilizer is getting sucked into your house water system and possibly the water main.


    Its also the reason why we have to install a back-flow preventer between a boiler and the domestic water supply

    amtrol explains it pretty well here:



    http://www.amtrol.com/pdf/MC8551 9003-038 06_07 TXT Mailer Home.pdf



    Hope this helps,





    Mike
  • paul_91
    paul_91 Member Posts: 62
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    what about a reducing valve after the main?
  • Michael Wilson
    Michael Wilson Member Posts: 46
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    check out this link, its quite helpful

    http://www.amtrol.com/pdf/MC8551 9003-038 06_07 TXT Mailer Home.pdf




    here's a cut and paste from the article



    To find out if you need a thermal expansion tank, follow
    this simple guide.




    1. Locate cold water pipe.



    2. Trace this line back toward the home’s main water
    supply.



    3. Look for a Pressure
    Reducing Valve (PRV),
    Backflow Preventer
    (BFP), or a check valve.
    Shut-off valves can be excluded.



    4. If any of the valves listed are
    present, a Thermal Expansion Tank
    (THERM-X-TROL® brand or equivalent)
    should be installed.
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