Boiler with hot water tank outflow drip constant

Discussion in 'Getting Started FAQ' started by John Haigh, Nov 25, 2021.

  1. John Haigh

    John Haigh New Member

    Hi would anyone have info as to why the outflow from boiler which is out of dwarf wall in conservatory drops constantly about a drip a second... I'm always topping pressure up. The system has large tribune hot water tank and a smaller red tank above with pressure valve. And another white small tank. The boiler is ideal... In name. Is it normal or is there a fix. Seems a lot of water wastage for a start. Thanks
  2. pppmacca43

    pppmacca43 Super Member

    So the most likely cause is one of the expansion vessels have failed and either need replacing or servicing. Sometimes when this happens the pressure relief valve will need changing too. This is a safety device that lets water out of the system should the pressure get to high due to a faulty expansion vessel. I would recommend you call a plumber who can work on boilers and cylinders to investigate and rectify.
  3. brian9999

    brian9999 Member

    If it is overflow from a pressure relief valve on pressured tank surely it should not simply come out of a dwarf wall and drip. Not according to building regs anyhow.

    Is it a condensate drain from condensing boiler, if so that may need looking at.

    Maybe an issue with pressure in the system or faulty relief valve.

    Could be temperature if pressure/temperature relief valve (which I doubt) but would be hot so be careful.

    Needs a properly qualified boiler/pressurised cylinder engineer to check in my view.

    My guess is condensate but could be completely wrong of course.
  4. pppmacca43

    pppmacca43 Super Member

    might be condensate but that wouldn't explain the constant need to top up the heating, which makes the most likely thing a fault with either the heating expansion vessel, the prv or both.
  5. brian9999

    brian9999 Member

    I believe the white tank is domestic hot water (DHW) or secondary and the red one is primary to central heating (CH) / cylinder coil for DHW.

    If the water is permanently dripping from the PTRV on the tank or the pressure valve under the red tank then this should be seen in the tundish. This will be hot water and should be vented somewhere safely as per the regulations. An issue here could result in ongoing primary pressure drop and need to top up the system. Could be valve or red expansion vessel.

    If opening post talks of outflow from the boiler rather that the tundish or overflow to outside (except for the pipe through the dwarf wall).

    The dripping through the drwarf wall would for me indicate condensate if the system is installed in accordance with regs (almost) and would not be requiring the pressure in the primary to be regularly filled with the filling loop using the pressure guage under the red expansion vessel.

    The white expansion vessel would be fed inlet combination control group or similar.

    It is possible that the "outflow from the boiler" is a red herring and the issues are all around the Tribune and its associated devices. There are possibly 2 issues, one from the condensate and one involving the pressurised primary circuit.

    I believe an engineer should be called to investigate.

    But that just my personal view.

    If John Haigh doesnt immediately understand what i have written, whether it is 100% correct or not he should not really be playing with the Tribuine and associated bits. I believe the failsafes there should prevent anyone from dying but someone could get scalded.

    Good luck John
  6. pppmacca43

    pppmacca43 Super Member

    yes the white tank will be for the cylinder and the red tank for the heating. he keeps having to top the boiler pressure up so its likely to be the vessel or PRV on the heating circuit and he has said the pipe is coming from the boiler also. Anything is possible but the first thing to check is the boiler expansion vessel and prv.
  7. John Haigh

    John Haigh New Member

    Thanks for all that info people.... One story on the house I bought which should alarm everyone... Whoever did the extention conservatory and electric under floor I would love to name and shame but guessing probs fleeting company and now now more or under another guise. When I re did the roof and insulated and left a couple of glass roof panels I had a rsj and hole in wall in taking this section of wall out it revealed this pipe which was underneath the plastered former outer wall... And guess what... It was hammered closed but was seeping behind this wall for about 10 years, I knew it was damp in there and blamed no doc under screed and concrete... It wasn't and two flooring replacements later was lucky I took some wall out as would never have known... So bloody dodgy that... Hammer it job done get paid leg it... Tossers. Incredible to hear for a lot of you... That's, the pipe I took across down and boxed in behind a deepened skirting.. And out there most convenient into my drainage channel to downpipe.... Re boiler I'll get some one out to have a look . Thanks
    pppmacca43 likes this.

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