Hello,

Following the other thread, I was going to buy a ball cock but I am
confused about what type one and type two are. I have tried to search
via google but I find sites that contradict each other. What are the
differences between the types and when is each used?

Thanks,

On Fri, 16 Jan 2009 12:22:36 +0000, Stephen wrote:

Hello,

Following the other thread, I was going to buy a ball cock but I am
confused about what type one and type two are. I have tried to search
via google but I find sites that contradict each other. What are the
differences between the types and when is each used?

A Part I valve has the outlet below the axis of the valve. A Part II valve
has the outlet at the top of the valve with a plastic deflector so it
comes out downwards (rather than as a fountain!) but still above the axis
of the valve. If the valve and the overflow are at the same level in the
tank you must use a Part II valve so that in an overflow situation the
valve outlet is not underwater, and water from the tank cannot be sucked
back into the mains if there's a sudden reversal of mains pressure (which
can happen). It's Water Regs for preventing backflow - ingress of
less-pure water into the mains.

If the overflow is sufficiently below the level of the valve a Part I
valve may be used. (In practice I only carry part II valves as they will
do in all circumstances.)

--
John Stumbles -- http://yaph.co.uk

My karma ran over my dogma