Kitchen mixer taps

Good point.

Indeed.

It's a heart-warming tale when you put it like that. ;-)

The point of my original contribution was simply to show, by example, the unexpected benefit of a kitchen mixer tap's post nozzle mixing feature as allowing a quick and simple method of backflushing the hot supply to remove any recalcitrent debris (or even an air lock) that may well have caused reduced flow rates.

I'm not saying this will cure every such reduction of flow but, since it's basically just a 5 or 10 minute job, it's a technique well worth trying.

Possibly worth mentioning apropos of nothing, that I was getting very poor flow from a kitchen mixer when fed with mains pressure hot and cold. In the end noticed that the whole spout lifted a little when water was flowing - rather like there was significant back pressure in the spout. Looking at the aerator on the spout showed that it was of a mesh construction and significantly scaled up. Unscrewing it and giving it a bath in some Fernox DS3 fixed that rather effectively.

/ That's a good possibility. Luckily, it's a large capacity tank and I did have the sense ...../

If installed correctly the overflow would be external...

The large capacity tank (if normally not 'full') would have allowed the extra head to build and produce the effect you observed.

Jim K

The overflow is indeed external, only an inch oe three above the normal fill level. I rather doubt the extra 2 to 4 inches of 'head' would have made any noticable difference in this case.

/ The overflow is indeed external, only an inch oe three above the normal fill level. I rather doubt the extra 2 to 4 inches of 'head' would have made any noticable difference in this case. /q

Your mind must have been playing tricks on you...

Jim K

I admitted as much, perhaps reinforced by a slight reduction of the cold flow due to pressure drop in the main feed caused by the demand from the header tank.