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What has gone wrong with my unvented system?

Discussion in 'Plumbing and Central Heating' started by dpm_dpmartin, 11 Dec 2017.

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  1. John D v2.0

    John D v2.0

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    Pressure relief valve. Basically a tap that comes on when the pressure goes above a set limit. It's piped to the tundish from the cylinder.
    For the primary circuit is usually 3 bar but since mains pressure can be over that, it's higher for unvented.
     
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  3. dpm_dpmartin

    dpm_dpmartin

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    Do I have one? If not, do I need one? Should I get one fitted? Can you tell? Don't be so gnomic... I see 2 things that look like valves near that dial - both are black, one has 4.5 bar written on it, the other has 2.25 bar.

    The only thing that I find interesting about those (as they seem pretty static) is that the figures are kinda like where those needles are on the dial. Spooky.
     
  4. dpm_dpmartin

    dpm_dpmartin

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    So, do I have both a PRV and a TPRV? How can one tell if they're kaput? Look like the same brand name as that dial.

    [​IMG]
     
  5. dpm_dpmartin

    dpm_dpmartin

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    So, 1 hour after both immersion heaters were turned on, we still have what you could call a cold dribble.

    But the water from the same tap I tested before is now a lot hotter. Pleasurably so. I'll leave it a little while longer... but not alone (don't trust it).

    The dribble down the tundish stopped when I ran off a bit of water from the hot tap.

    The black needle on that dial is now at 2.4 rather than 2.6. Remember, it was at 2.8 in the first picture... so at least the dial works! Yay!
     
  6. Lower

    Lower

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    Seriously? Worse case is that the hot water reaches central heating temp.

    The PRV is clearly working. So how is this potentially dangerous?
     
  7. DH6

    DH6

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    80 degree hot water is rather dangerous!
     
  8. St0rmer66

    St0rmer66

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    So if that's the case tell me why the overheat thermostat (usually) cuts power to the zone valve and closes it? If you're G3 qualified you'll know this ;) .
     
  9. dpm_dpmartin

    dpm_dpmartin

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    What I have genuinely loved about this forum, for ages, is the way some people like to have a discussion, like to try and educate, like to open up the mind to thinking and, completely opposite to that, the way some others will try to close down any discussion, try to hide information and pretend that what they work on is simply too abstruse for a layman to comprehend. Of course, they'll hide behind "call a professional" all the time, and that is what has been done in any situation pertaining to boilers and central heating (by me, as already stated), but it truly blinkers their vision, because instead of answering questions, they fall back to a form of protectionism and they try to pose their own questions (to the OP and other helpful forum members) that are solely intended to belittle others, challenge them and dent their confidence. This is not how people will learn anything effectively, so they are broken forum members in this regard. I prefer the folk who say - "this looks like this is wrong, and maybe you could try this to validate if this happens, if it does it probably points to this"; then at least you can talk to the professional who visits your home. Heck, it might even make it cheaper. I think - stereotypes inexcusable - that the forum members who try to shut down conversations must really like it when little old ladies call them out to just "fix it". I'm not saying they're an easy mark, but they could be for the unscrupulous. I learned quite a bit yesterday - and I liked it. Until the thread descended into posturing, again.
     
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  11. St0rmer66

    St0rmer66

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    You had the answer on the first page. All the rest has been useless drivel. The expansion vessel will be completely flat, I'd bet money on it. The pressure gauge you're reading is on the inlet as far as I can tell so the rising pressure won't be seen as it's after a non-return valve. TPRV or PRV *may* be passing but usually they're either gone or they're not. You should be able to use both immersion heaters once everything is working correctly, that is not part of the fault.

    And you STILL need to get someone qualified round. As we said before.
     
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  12. St0rmer66

    St0rmer66

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    Sorry you don't like the COMPLETELY FREE advice from a qualified person on their day off. I won't be troubling you again, that's for sure! :rolleyes:
     
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  13. John D v2.0

    John D v2.0

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    Some free advice is worth what you pay for it, some is with its weight in gold.
    The failures on this forum are mainly due to poor admin/moderation, go and look at electricians forums or plumber's forums for how it should be.
    On the other hand they are more commercialised, this place is more like the old Usenet.
     
  14. John D v2.0

    John D v2.0

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    The assembly includes a pressure reducing valve as well as a pressure relief value (seriously)
    The first reduces the incoming supply to 2.25 bar so that the cold starting point isn't too high, and the second releases the pressure if it goes too high.
    There's always a possibly that the pressure reducing valve has a fault, because after running any notable amount of water from the tap, the pressure guage (which is after the pressure reducing valve) should reduce to match the set pressure on the reducer. However it could well be the guage with the issue.
    Same reason you can't use speed fit within 1m of a boiler casing.
     
  15. Pin 5

    Pin 5

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    Don't under stand the reason for the hepvo trap?
     
  16. oilboffin

    oilboffin

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    Well I muSt say I think The op on this article has descended into nothing but an ungrateful and arrogant so and so the very fact that so many good people have tried to help him and he's thrown it all back in their faces I call it disgusting.Bob
     
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  17. EAST61

    EAST61

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