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Discuss Shower running lukewarm on hottest setting in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Lewis9090

    Lewis9090 New Member

    I have a problem with my shower - it started dropping in temperature to where even on the hottest setting it now runs lukewarm at best. Previously happened about 3 months ago and was then taken apart and adjusted the flow from the inside which seemed to solve the problem for a while, albeit I had to have our boiler on preheated water to ensure it was hot enough, instead of the 'eco' setting (combi boiler). The temperature has steadily dropped until now its unusable. Taking it apart previously was a ballache, my Dad did it who is an all round handyman but hates plumbing so will loath to do it again! I was wondering if anyone knew the cause of this? Other relevant info is other hot taps upstairs and downstairs are all fine, the shower has a mixer tap and our boiler is kettling relatively often.

    Thanks, Lewis
  2. Stu-B

    Stu-B Active Member

    I’d say the showers thermostatic cartridge has failed, especially if every other hot outlet is fine.
    • Agree Agree x 1
  3. Svenedin

    Svenedin Member

    If it is straightforward to do and obviously after isolating both the hot and cold supply check the inlet strainers on the shower mixer. They can be rinsed under the tap, de-scaled or replaced as necessary. You mentioned the boiler is kettling which suggests a hard water area. It is probably the thermostatic cartridge which can be taken out, cleaned and de-scaled but it may actually have failed completely. When the cartridge has been taken out and put back it is advisable to check any anti-scald settings in the mixer (see manufacturer’s instructions). If the mixer valve is old it may make sense to replace it completely as thermostatic cartridges can be quite expensive depending on the exact mixer. I’ve had problems like this over the years as my water is very hard.
  4. Harvest Fields

    Harvest Fields S. Mod Trusted Plumber GSR Top Contributor!!

    Or filter blocked possibly ?
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