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flexis to radiator - is this my heating problem

Discussion in 'Plumbing and Central Heating' started by zuber ali, 31 May 2021.

  1. zuber ali

    zuber ali

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    Hi All,

    i have a rad in my house which randomly decided to stop working, all other rads are fine.
    i have checked TRV and Locksheild vales, all fine, switched off all rad to force water through the one. no luck. released air. no luck.

    decided to lift the floorboards. i found a isolation valve connected to a flexi which runs to the rad flow and return legs. no idea why it was done like this, but google tells me its bad practice, from what i gather the risk is flexis not being able to take the high temps and eventually splitting. this flexi in question is NOT split,

    i will get the flexis changed, but in your experience, could it still be the flexi causing the issue seeing as the entire branch serving this rad is cold to touch. from as far back as i can see.

    ive had a plumber tell me its the flexis causing the problem and quote £400 to change, but if the only issue with flexis is leaking i dont see how this can be the cause of lack of heating as there are no leaks and the entire branch is cold before the flexis, so presumably the problem lies further back (maybe??)



    thanks
     
    Last edited by a moderator: 31 May 2021
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  3. ianmcd

    ianmcd

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    you actually get flexis for heating systems, but if the ones you have are standard tap ones they are probably blocked
     
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  4. oldbuffer

    oldbuffer

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    1. If there is no flow through a pipe which is meant to be hot, it will not heat up, and will only warm by conductance from the nearest hot point.
    2. I wouldn't use an isolation valve on a heating circuit unless it is specifically designed for such use. The ordinary "85p" valves can't take the constant high temperatures, and generally leak, although this is not the problem you have.
     
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  5. oldbutnotdead

    oldbutnotdead

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    The internal bore on tap flexis is very small so presents greater resistance to the flow of water- if there's an easier route then the water will follow that. They'll block very easily, if they're looped then a very small air bubble will airlock the system and be a pig to shift. £400 is a bit rich- some Speedfit couplers and a bit of tube & you could probably DIY it
     
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  6. KenGMac

    KenGMac

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    The water is a C/Heating system is NOT "clean" but tends, over time to become contaminated with metallic rust from the inside of the Rads, hence the need for Mag Filters to remove the worst effects of sludge and metallic bite building up.

    The Flexis in the system that you have are probably well blocked up with all sorts of filthy black gunge that inhabits most C/Heating systems.

    Ken.
     
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  7. conny

    conny

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    Be interesting to see the state of the flexi's after you remove them, especially if they are the cause.
     
  8. sxturbo

    sxturbo

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    I've had this in my last house, had about 5 heating specialists who couldn't figure it out.

    In the end me and my old man decided stuff it, let's take the flexis out,

    The flexis were blocked from there own rubber, they definitely weren't for heating systems,

    The guy who installed the heating seemed to like fitting bathroom fittings in the system as he also fitted a number of tap isolators in the system, we subsequently took these out aswell and the heating worked great after that.
     
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