"Roger Mills" wrote in message
...
In an earlier contribution to this discussion,
ARWadsworth wrote:



I am sure that I have seen variations of the W plan for gravity HW
using a 2 port valve!

I think you're confusing it with C-Plan, which does that.

It was half and half. It was definately neither. I was ripping it out for a
plumber who was installing a combi.

I doubt W plans will make a comeback. A W plan cannot meet part L of
the building regs as it does not allow total independant control of
the HW and CH circuits.

W-Plan is fully pumped with a diverter valve, and *does* provide
independent control and a boiler interlock, so I don't see why it wouldn't
meet Part L.

If you actually mean C-Plan, that also provides independent control and
boiler interlock. It's actually devilish cunning in the way that it uses
the auxiliary change-over contacts in the single 2-port valve.
--
Cheers,
Roger

The reason I suggested that a W plan would not meet Part L is because you
have to heat the hot water up regardless of need on a W plan and Best
practice for boiler controls says that the HW and CH should be provided with
independant time controls.

Cheers

Adam