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Installing a WaterCop and now I have dripping backflow preventer

geoff53geoff53 Posts: 3Member
I installed a device called a WaterCop yesterday. Basically, this is a device that you install by cutting into the main water line just after the meter. The device is a motorized shut off valve. When the main unit receives a signal from one of the wireless sensors, it shuts off the main water valve limiting the damage by water. Several hours later I noticed water dripping from the Backflow preventer valve. In the reading I have tried to do online, this is not an uncommon thing to happen when the pressure is lowered going to the furnace. My questions are these. Was there a way to have prevented this? Should I have shut off the boiler during the time (45 mins) that I was doing this work? Now that it is leaking, do I need to replace it? I purchased another one to swap out ( union fittings so it won't be difficult) but wondered if this will clear itself and stop dripping? Was this caused by the interruption of the water pressure and then when the water was turned on, it sent debris to the Backflow preventer causing this problem? Thanks for any help you can provide..



  • Jamie HallJamie Hall Posts: 12,152Member

    if a backflow preventer is dripping from the atmospheric vent (assuming that it is of the reduced pressure zone type, and not just a double check or something) it indicates that one of the valves inside it is leaking.

    You might be able to flush it out, if it is a matter of debris preventing the valve from seating, but it also might need replacement.

    You can tell -- within reason -- which valve; if it only drips when the water pressure on the downstream side is higher than the feed, it is the second check.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • geoff53geoff53 Posts: 3Member
    backflow preventer leaking

    Thanks for the information. Not exactly sure how to tell what kind of valve it is, I will try to upload a picture of it for your review. Can you tell from the picture what kind of valve it is? Would you recommend just replacing it? Its affordable and I can alway play with the old one to see if I can find the problem and fix it, then save it as a spare.. your thoughts?

  • hot_rodhot_rod Posts: 12,590Member
    looks like

    that backflow preventer has leaked in the past based on the water deposits.

    Three seals need to be made inside. First the spool that closes off the drain port, then the seal on both checks. Often on very first start debris is stuck at that first seal. They seep or drip from day one.

    Another cause is water hammer in the system caused by a fast closing valve and high system pressure. Wash machines, dishwashers, icemakers, and outdoor sprinklers all use fast acting solenoid valve. A water hammer arrestor near the fast acting valve is the proper fix.

    They also drip or spit when they are doing their job, reacting to pressure imbalance.

    Really all backflow preventers should have a drain tube to the floor or a drain, they all discharge at some point in their careers
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • geoff53geoff53 Posts: 3Member

    Thanks Hot Rod for the advice.. so I am presuming it would be your recommendation to swap it out at this point... am I correct on that?

  • hot_rodhot_rod Posts: 12,590Member
    yeah, but

    something may be causing the discharge and a new valve may do the same. Here is a cutaway of what is inside a typical BFD.

    If you speak Dutch you can watch our You Tube from our Netherlands branch :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Harvey RamerHarvey Ramer Posts: 2,211Member
    Hot Rod

    Have you given up turning wrenches and just work for Caleffi now?

    Also give your wife Ellen a big THANK YOU from me. Her video tutorials have proved invaluable to my business.

    Ramer Mechanical
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • hot_rodhot_rod Posts: 12,590Member
    still tinkering

    for friends and neighbors on hydronic, wood, and solar systems I scattered around here. I have a few hydronic, solar and wood fired systems on our property. Always upgrading and trying new components on my systems.

    I'm a full time trainer for Caleffi now, that takes me across the U.S. and Canada.

    Ellen is seldom off the phone, I tell her hi if she stops talking.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • ZmanZman Posts: 5,545Member

    A problem I have seen with the leak detector is that the water valve gets shut off because of a dripping toilet. The backflow preventer detects lower pressure in the house and allows water to drip out of the boiler loop into the vent. The boiler then depressurizes and locks out. This causes a much bigger problem, the house freezes.

    The solution is to put a spring check upstream of the backflow preventer.

    I have been curious if this is the sign of a bad devise or if it is normal. Hotrod?

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rodhot_rod Posts: 12,590Member
    drip, drip, drip

    I have heard that solution numerous times now, adding an additional check upstream.

    Keeping in mind now you could have a total of 4 checks in a row! As some fill valves also have intergral checks.

    A contractor I met up in Canada last fall tells me buildings with flushometers on toilets and urinals can be problematic for backflows. He too adds that additional check, and tells me it works to prevent drips.

    Pretty much every backflow device I saw installed on jobs as I traveled in Europe had that air gap fitting and a pipe to a floor sink or drain. Seems if the BF device is build sensitive enough to protect, it can be prone to rouge, errant discharge.

    This is top on my list to try and test once our new wet lab is finished in Milwaukee. Once I can duplicate the condition I'll try hammer arrestors and other ideas.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
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