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Discuss HOT, very hot, too hot, hot water, stored, cylinders, in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Ted808

    Ted808 Plumber GSR

    Hey guys
    I've had a two jobs where cust is complaining of hot water being too hot. One is an old UNVH cylinder and the other is a very, very old hot water-yellow jacket and cold storage tank set-up.
    Now I'm wondering this is - why has the water over time apparently got hotter?
    Bear in mind, in both cases the cylinder stat set to 60*C ( as accurate as these can be over time...that's another story ) but the water is coming out at the furtherest tap about 57* - so that's a little too hot. I would like it nearer 42*-44*. Nothing has changed on the system/s but I realise weather is warmer- so maybe shorten heating time?
    I'm not going to put in blender valves in.
    Someone suggested, limescale build up on the cylinder is holding on to heat so that even when timer/heat is off it continues to generate heat?
    What's your thoughts on this?o_O
     
  2. Chalked

    Chalked Plumber GSR

    Cylinder stats go out over time.
    Just turn it down to desired temp and ignore the number
     
    • Informative Informative x 2
  3. Stigster

    Stigster Plumber

    The thing is it should be hot, too hot to put hands under. A blending valve is the proper way to go about it rather than turning the cylinder temp down if it's at 60 - 65C. Obviously if it has crept up to 70 or more then turning it down to around 65 is the right thing to do. It's certainly worth getting a temperature reading right at the cylinder to know where it's really at.
     
  4. townfanjon

    townfanjon Trusted Plumber GSR

    Whatever the HW temp is leaving the cylinder , it will only be a few degrees cooler when it gets to the taps . Blender is the only way .
    Depending on the cylinder capacity and therefore height it also has a bearing on the temp , cylinder stat 1/3 up from bottom , tall cylinder 210 / 250 etc stat set at 60 it will probably leave the cylinder at 65 ish .
     
    • Agree Agree x 1
  5. leesparkykent

    leesparkykent S. Mod

    Is the vented cylinder on a Y plan?
     
  6. Ted808

    Ted808 Plumber GSR

    Chalked would you say that having 42* at the tap will still get the cy
     
  7. Ted808

    Ted808 Plumber GSR

    Does it matter?
     
  8. Ted808

    Ted808 Plumber GSR

    How do you come to this conclusion? I mean is there some printed info on this. Just trying to understand and learn as much as possible- cheers
     
  9. townfanjon

    townfanjon Trusted Plumber GSR

    Its just general unvented knowledge pal . When HW is heated it “ stratifies “ I suppose its a bit like in imaginary layers . So with the stat being a lot lower than the top it stands to reason the top is a lot hotter and also because the cylinder is under pressure it gets to the taps in seconds hence the HW doesnt loose many degrees . TMV’s are the only way forward .
     
    • Agree Agree x 1
  10. leesparkykent

    leesparkykent S. Mod

    Yes.
     
  11. Ted808

    Ted808 Plumber GSR

    Why? Please explain a little more.
     
  12. Ted808

    Ted808 Plumber GSR

    I have two different situation's - one it's a vented cylinder on a Y plan and the other is an Unvented on S plan. In both cases the water has seemed to increase in temp over time- I am trying to understand why this is- besides seasonal changes and general design, could there be a proper reason or are both customers imagining it?
     
  13. Last Plumber

    Last Plumber Plumber GSR

    I might be missing what you want to know here!
    If you've set the Cyl Stat to 60 C (like you're supposed to) and it is 57 C at the draw off point, what's wrong?
    If it is just that the customer is burning themselves, as Townfanjon said, you need to install a TMV. The cylinder is set at that for a reason isn't it?
     
    • Like Like x 1
    • Agree Agree x 1
  14. Ted808

    Ted808 Plumber GSR

    The point is the customers feel that the water temperature has increased over time. DOES this seem probable?
     
  15. Ted808

    Ted808 Plumber GSR

    What's the difference if it's Y plan or not? Unvented or vented.
    I know the cylinder stat has to be set 60*.
    I'm just saying , blender valves are not generally routinely installed on domestic systems, not that I've seen.
     
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