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Discuss Water heater with tap blow off??? in the Plumbing Forum area at

  1. Karl

    Karl Member

    hey guys wondering if you can help, probably can because your experience is a lot longer than mine! I looked at a job where the customer wants to change basin taps, there is a old water heater under the basin, which has no pressure relief valve. I said this to the customer and they seem to think the blow off is combined in the tap!? If this is true I’ve never heard of or seen such a thing! He said it was fitted in the 90’s which is before my plumbing time lol if this is true I’d need to source a special tap? Which has a spring loaded gut? Also on closer inspection there’s a valve under the basin which again I’ve never seen! I am G3 qualified but like I say never heard or seen such a thing. Hopefully you guys can help and I’ve attached some photos





  2. snowhead

    snowhead Plumber

  3. Karl

    Karl Member

  4. snowhead

    snowhead Plumber

    I've corrected that for you..
    • Agree Agree x 2
    • Like Like x 1
  5. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Yea drippy taps you can still get them but there not cheap about a ton

    The new design doesn't swap like for like with the old so change of pipework

    City plumbing can get them or you can get direct
  6. Karl

    Karl Member

    Oh nice! Will see what the customer wants to do
  7. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Just relieves pressure , bit like a ventpipe .
  8. chris watkins

    chris watkins Plumber

    They are called "vent taps" as the washer is on the end of the tap spindle which goes right the way down to close the incoming cold water (bottom connection) which then runs to the water heater inlet. The hot water then comes from the heater back to the tap via the upper connection which is un-restricted so the heater is open vented i.e. when the water is re-heated & expansion takes place the extra water is discharged out of the tap spout. This is why they drip after use.
    A common problem is over tightening of the taps as people think it has not been turned off properly.
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