geoff wrote:
In message 1242013644370821660.533313timdownie2003-nospampleaseyahoo.co.uk@reader80
.eternal-september.org, Tim+ writes
geoff wrote:
Can anyone give me a bleedingly obvious reason why two identical WCs with
maybe a metre difference in head are performing so differently?

The higher one seems to suck like a ... , and leaves only just enough
water to cover the "S" bend. The other one circulates and leaves a normal
amount of water in the pan

I don't actually want to get too involved (for obvious reasons0 but can
anyone give a few pointers as to why the first seems to have an over active syphon?





Is the stack properly vented? I would guess that the falling water from
the higher loo is capable of exerting a greater suction because the height
of the fall is greater than the lower one. In fact, if water is being
pulled below the trap level in the upper pan, the lower one may be causing
air to be drawn into the soil pipe via the upper pan.

This is something that has changed in the past 12 months since I was last
here (which I should have mentioned). What you are alluding to is a
design problem which would have been there from build.




Well if its got a Drago (?sp) valve or similar instead of being open vented
the valve may have stuck since you last saw it.

Tim