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Discuss Cast Iron style rads on 10mm in the Central Heating Forum area at UKPlumbersForums.co.uk.

  1. Last Plumber

    Last Plumber Plumber GSR Top Contributor!!

    Typical.

    Everyone loves the stylish idea but no-one loves the stylish price.

    No-one appreciates the stylish time you put in either.
     
    • Agree Agree x 3
    • Like Like x 1
  2. Ric2013

    Ric2013 Plumber Top Contributor!!

    I think I hired a chaser for £40. But I had my own vacuum.
    Agree 2kW is probably too much on 10mm - in any case, 2 kW was a figure plucked out of the air, not an actual figure relating to the OP's question.
     
    • Agree Agree x 1
  3. Dkdc71

    Dkdc71 Member

    The only thing 10mm should be used for is oil line every time I come across it I remove it
     
    • Winner Winner x 2
  4. Ric2013

    Ric2013 Plumber Top Contributor!!

    Then you are in disagreement with the Copper Development Association which states:

    Where
    the chosen diameter is too large, so
    that the velocity is less then 0.5 m/s,
    then sludge can settle in the piping.

    and in some cases would therefore prefer to see 10mm used to get sufficient velocity.

    Of course, you are allowed to be in disagreement, though.
     
    • Agree Agree x 1
  5. Last Plumber

    Last Plumber Plumber GSR Top Contributor!!

    I agree.
    There is no need to over size pipework and no excuse for under sizing it.
     
  6. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    Ahh, the old 1,000,001 ways to pipe a rad argument... :p
     
    • Funny Funny x 1
  7. Ric2013

    Ric2013 Plumber Top Contributor!!

    . . . and every single one of them is right?
     
    • Agree Agree x 2
    • Like Like x 1
  8. Last Plumber

    Last Plumber Plumber GSR Top Contributor!!

    No.
    They are not all right.
    Pipe size can and should be calculated out.
    There are 'rules of thumb' of course and we all use them but they come from experience normally. Experience of everyday /common work.
     
    • Agree Agree x 1
  9. Gasinspect

    Gasinspect Member

    Our house was done with 8mm years ago. I was skeptical and promised myself I would redo in 15 but actually works OK even on large k2. Yes takes a while to heat up but maintains fine, just depends on lifestyle. So never got around to changing. If they just want fast short bursts of 2 hours morning and a few in evening then might struggle.
     
  10. Supermeteor

    Supermeteor New Member

    Here's a link to a manufacturer who feels microbore's OK FAQ's Questions Cast Iron Radiators | Ribble Radiators
    The 10mm can be disguised or concealed if the aesthetics are a big issue. I had an 1800 x 600 double convector running satisfactorily on 8mm microbore for 34 years at our house, installed from new in 1977 by the developers (until the in screed F&R pipes succumbed to corrosion...) Instinctively, it feels wrong, but it worked.
     
  11. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    I do note the very careful phrasing used. 'can' be used. That is a world away from operate at full effeciency, or perform just as well kind of thing. Id wager 10 hard earned pence they would only say "at a push".
     
  12. Supermeteor

    Supermeteor New Member

    I know what you mean, I only provided the link so that the original poster could, were he to so choose, investigate further. (and I might benefit when he posts the results)
     
    • Like Like x 1
  13. Ric2013

    Ric2013 Plumber Top Contributor!!

    In fairness, years before I was qualified, I used a mixture of 22 Cu, 15 Cu and 10mm Hep to make a manifold heating system where I was living. The 15 was for a DPDC rad that needed more than 10. The 10mm Hep was for everything else. The 22 was to the manifold (which was, itself, made from 22), and the cylinder.

    According the the pipe sizing method of the Copper Developmnent Association or whatever it's called (as previous post) that I used (a slightly simplified version to the City and Guilds Level 3 textbook method IIRC), 10mm was excessive for some of the rads, but I wasn't going to buy yet another roll of pipe for the smallest rads.

    It actually worked very well indeed. Since there was minimal water content in the pipework, the rads warmed up quickly. Since the system was to some extent balanced by the resistances in the flow and return runs being roughly equal prior to any fine tuning using the lockshields, the system balanced quite easily and, since none of the lockshields needed cranking down massively, the system ran quietly. The pump was an old UPS 15-50 on the lowest speed to allow a 10°C drop. This was in a three-bedroom, 8 radiator house.

    If I'm working on an existing system, using 15mm gives me a margin of safety that allows me to know my pipework is not restrictive. This is useful if a larger or additional radiator is later substituted, or where I do not know how the runs are made, how much available head there is, etc. But, if I were starting from scratch, I have no problems with microbore - I have seen it work very well. The only problems IMO is that the system needs to be kept clean, that microbore is more vulnerable to damage than half-hard 15mm, and that, visibly connected to a fat old iron radiator, it might look a bit strange.

    I maintain that flow rates should not be a problem if the pipework is sized as it should be.

    Take Classic 3 Column Cast Iron Radiators 500mmRRP 17 and use a 500 high by 630 wide radiator (10 section) as an example. Output is 1800btu, which is about 0.5kW. Conveniently (saving me looking it up properly), this link (http://copperalliance.org.uk/docs/l...eating-systems-pdf.pdf?Status=Master&sfvrsn=0) suggests 5kW at an 11°C drop needs 109ml/s which is 6.6l/m. So a 0.5 kW radiator needs only 0.66l/m: a mouse's fart. On 10mm, the loss of head for a 0.5kW radiator running at an 11°C drop, is a mere 0.006 metres per metre run of copper pipe. In fairness, we tend to use a 20°C temperature drop these days, and there are other factors involved, so this is only an approximation, but you see my point. By all means shove more water through the radiator than its output requires to allow a fast warm-up, but be aware that the condensing boiler will not then run in condensing mode, and the pump will be using more electricity than it needs to.

    You'll then use the lockshield valve on the radiator to reduce the flow to the 11ml/second that the 0.5kW radiator actually needs... and the radiator will take LONGER to warm up because of the slightly increased water content of the system.

    As others have said, the point is to size the pipework properly. Too fat a pipe will be less of a problem than too thin a pipe, but the ideal is a properly sized pipe.
     
    • Agree Agree x 1
  14. Dkdc71

    Dkdc71 Member

    Only time we would come across 10mm on a heating system was when it was an old system with blockages and not working properly haven't seen it been used on a new system in 25 Years half inch is the standard for rads here
     
  15. Ric2013

    Ric2013 Plumber Top Contributor!!

    Where is there, Dkdc71? I see loads of microbore in Essex in houses built since 1980.
     
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