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Discuss Any reason 1/2" Portsmouth (Part 1 ballcocks or FOV) are still sold at all? in the Water Regulations area at

  1. Ric2013

    Ric2013 Plumber Top Contributor!!

    To cut a long story short, I started reading the the WRAS Water Regs book again:

    G16.1 d states that a G1/2 size valve (do they mean a 1/2" valve as opposed to, say, a 3/4" valve?) must be 'constructed so that the water shut-off level may be altered [.] without bending the float lever.' So why bother making Part 1 valves of that size at all?

    I suppose you could argue that replacing a valve does not constitute installing one so you can fit a non-compliant valve as a replacement? Is that why these are still sold?

    Just wondering as usual :)


    Last edited: Dec 30, 2015


    yep. They can be replaced but why on earth would anyone bother. Just use a part two.
    • Like Like x 1
    • Agree Agree x 1
  3. Ric2013

    Ric2013 Plumber Top Contributor!!

    They were out of date in 1962, so I have no idea either. Still finding loads of them in service though.
    • Agree Agree x 1


    I changed one yesterday funnily enough.
  5. chris watkins

    chris watkins Plumber

    Part 2's are only made in G1/2 & 3/4 sizes so if you want anything bigger it is still the Part 1.

    Also Part 2 is limited to the orifice size that can be fitted I seem to remember.
  6. Ric2013

    Ric2013 Plumber Top Contributor!!

    That's my point: specifically, why bother making the half inch? What does the G stand for, by the way?

  7. chris watkins

    chris watkins Plumber

  8. Terry P

    Terry P New Member

    Many existing WC cisterns still in use have a Portsmouth float operated valve (part1), when the valve is in need of replacement the use of a part2 will not fit due to its air gap back flow protection of the water outlet at the top by means of the bent plastic water delivery spout sticks up too high for the cistern lid. The part 1 can be installed providing back flow protection is installed in the supply pipe in line with The Water Supply (Water Fittings) Regulations 1999.
    • Like Like x 2
  9. cr0ft

    cr0ft Trusted Plumber GSR

    Where I've seen this though I just replace them with a side entry adjustable arm float valve tbh.
    • Agree Agree x 1
  10. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    As long as there is space to do it I have come across a couple where I couldn't
  11. moonlight

    moonlight Plumber GSR

    Again if there is space, I would update to part 2 unfortunately at times someone has cut the hole in the F & E to near the top.
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