Kitchen tap.. mixer post type.. bar to left for hot water... bar to right for cold
Cold... no problem... Hot dribbles UNTIL you flush the loo... then everything is OK... for a while... Gas boiler... floor mounted King Fisher with pump... electric Immersion and storage separate... 3 bar Stewart pump in the system . Water downstairs only... Tower rail plus two thermostatic controlled radiators
Any ideas please

You most-likely have debris in the cartridge. Close water, remove cartridge, flush it, look inside the faucet cavity, make sure there is no debris, reinstall cartridge. See if that helped

Milo

I cannot translate all your terms but sounds like excessive pressure build up in water heater. When you flush the loo the pressure is relieved back through the cold water system. Opening any other tap (hot or cold) should also stop the dribbling of the kitchen hot tap. You need to install expansion tank on cold water input line to water heater.

What do you think Milo?

I cannot translate all your terms but sounds like excessive pressure build up in water heater. When you flush the loo the pressure is relieved back through the cold water system. Opening any other tap (hot or cold) should also stop the dribbling of the kitchen hot tap. You need to install expansion tank on cold water input line to water heater.

What do you think Milo?

Ooops, misread that "loo" for something else. Thank you for your excellent analysis and advice. Milo