The water level is only a smidgin below the overflow Can you increase it,
It is a dual flush syphon and seems to start oK with either momentary actuation of the lever (1 gallon flush) or holding down the lever (2 gallon flush)
There is probably a slight bias to washing down on one side
Not sure. The pipe was the one supplied with the cistern, one piece with a swept bend ready formed. It is all boxed in so difficult to check if a larger size would be admissible. Whilsty I might be able to bodge in a lerger pip into the back of the pan, I suspect that the outlet of the cistern will be designed for a single size pipe.
One other possibility comes to mind. The Pan outlet is horizontal and runs into a pipe also horizontal (2.5 degree fall actually) about 7 feet long before joining a conventional vertical stack. Normally, the pan would be much closer to the stack. So, does the effect of a 'plug' of water falling down the stack contribute to the flush by suction??
Thanks for the suggestions JB
The domestic authorities have ordered that the floor be tiled and the place decorated so I'll take out the bog and the bidet (posh footbath!!) and investigate. Someone else mentioned scale. We have very hard water so I'll get some acid to descale under the rim which may have some blocked jets hence the slight sideways bias during the flush.
I have also just timed a flush. It takes a full 20 seconds for a 2 gallon flush. Is this a long time? Perhaps we could have a survey amongst DIY groupers?? How long is your flush??
Regards
Bob