On 07/10/2020 16:01, Jimk wrote:
Any top tips to avoid draining down a hw cylinder in order to
change a tap washer?

something that I can bung in/over the seat & reduce losses whilst
I fart with the jumper?

Or ought else?

TIA

Depending on the design, there is often a gate valve somewhere near tehe
tank (or possibly from cold cylinder to tank) that you can turn off
(recognisable by round pressed-steel handle). Or you can sometimes put a
rubber bung in the bottom of the cold tank, in the pipe that feeds the
hot cylinder.

If none of these options are available you may be able to make that tap
"run dry" by running other hot water taps either nearer to the cylinder,
or below the one you want to work on.