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TKW's avatar
TKW
Explorer
Aug 27, 2017

Black Water Tank San-T- Flush Vacuum Braker Leak

I have a occasional leak under the bathroom sink. It takes me a while to figure out it's from the San-T-Flush Vacuum Breaker. It works Ok when flushing. However, it starts to leak as soon as faucet is turned off and won't stop until the inlet hose is detached. I have it taken out to check for debris and lubricated with WD40 without success. I checked on the manufacturer's (Swan Industries in Oregon)web site, it says: "Back-seepage upon shutting off the flow of water is normal." My original thought was to give them a call for a replacement part. I now have a second thought after reading this. Am I suppose to permanently wrap a towel around it?

I read on other forum and found a suggestion to replace the plastic part with a brass one. Since I am not experience with these plastic fitting. Can anyone tell me if this plastic fitting is compatible with brass vacuum breaker? Or do I have to change the fitting as well?


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12 Replies

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  • 3oaks's avatar
    3oaks
    Explorer
    Aug 28, 2017
    Lynnmor wrote:
    Some brands or models have the check valve incorporated as a unit.
    I was referring to the plumbing in #1nobby's picture.
  • Lynnmor's avatar
    Lynnmor
    Explorer
    Aug 27, 2017
    Some brands or models have the check valve incorporated as a unit.
  • 3oaks's avatar
    3oaks
    Explorer
    Aug 27, 2017
    #1nobby wrote:
    TKW wrote:

    If yours doesn't leak, can you tell me the make & model of you brass vacuum breaker? Is it just a check valve or vacuum breaker?


    No idea of the brand name.

    I THOUGHT it was just a check valve. I'm pretty new to this RV game. Learning everyday.

    However....I only use it at the dump station for a couple of minutes.

    Notice that I store toilet paper just below it..........

    The brass fixture is the vacuum breaker. The white fitting screwed into it is a CHECK VALVE.

    They are two separate plumbing items.

    Brass Vacuum Breaker
  • _1nobby's avatar
    _1nobby
    Explorer
    Aug 27, 2017
    TKW wrote:

    If yours doesn't leak, can you tell me the make & model of you brass vacuum breaker? Is it just a check valve or vacuum breaker?


    No idea of the brand name.

    I THOUGHT it was just a check valve. I'm pretty new to this RV game. Learning everyday.

    However....I only use it at the dump station for a couple of minutes.

    Notice that I store toilet paper just below it..........

  • TKW's avatar
    TKW
    Explorer
    Aug 27, 2017
    #1nobby wrote:
    #1nobby wrote:
    #1nobby wrote:
    Since it is easy to uncouple.....just have to loosen the retaining flange nuts....or whatever they are called.....just replace it with a new one. How long did the plastic one last?


    And no...it shouldn't be leaking.

    Mine in brass.


    My mistake.
    I assumed it was the check valve for the sani flush.

    I should have read the complete description.

    Mine is under the lavatory sink and does NOT leak.


    If yours doesn't leak, can you tell me the make & model of you brass vacuum breaker? Is it just a check valve or vacuum breaker? My plastic one combines a check valve & a plunger that shuts when pressurized, and vents when flow is shut-off. The problem is the residual pressure in the line that is not high enough to keep it shut and leaks. It only stops when the inlet hose is detached.
  • TKW's avatar
    TKW
    Explorer
    Aug 27, 2017
    Lynnmor wrote:
    Of course it leaks, it says so right in the instructions:

    Catalog

    ATMOSPHERIC VACUUM BREAKER/
    CHECK VALVE
    (571 Vac Chk) must be 6” above flood
    rim of the highest fixture connected
    to the wasteholding tank. (ASSE
    1001-02; device shall not be installed
    where the venting of water from the
    device during normal functioning will
    cause damage.


    I simply eliminated the stupid thing. Just made sure that there was a check valve in the outside hose connection.


    Agree, it's stupid to have it located in the vanity under the sink. Eventually, the floor will rot out if undetected.
  • neschultz's avatar
    neschultz
    Explorer
    Aug 27, 2017
    I replaced it with a brass check valve. My instructions also said it needed at least 25 psi to seal (don't turn that valve on slowly or camp anywhere with <25 psi water pressure).
  • _1nobby's avatar
    _1nobby
    Explorer
    Aug 27, 2017
    #1nobby wrote:
    #1nobby wrote:
    Since it is easy to uncouple.....just have to loosen the retaining flange nuts....or whatever they are called.....just replace it with a new one. How long did the plastic one last?


    And no...it shouldn't be leaking.

    Mine in brass.


    My mistake.
    I assumed it was the check valve for the sani flush.

    I should have read the complete description.

    Mine is under the lavatory sink and does NOT leak.
  • Lynnmor's avatar
    Lynnmor
    Explorer
    Aug 27, 2017
    Of course it leaks, it says so right in the instructions:

    Catalog

    ATMOSPHERIC VACUUM BREAKER/
    CHECK VALVE
    (571 Vac Chk) must be 6” above flood
    rim of the highest fixture connected
    to the wasteholding tank. (ASSE
    1001-02; device shall not be installed
    where the venting of water from the
    device during normal functioning will
    cause damage.


    I simply eliminated the stupid thing. Just made sure that there was a check valve in the outside hose connection.

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