On Aug 29, 6:00 pm, "Arthur2" wrote:
Did it stop working all of a sudden or over a period of time?

Very much, suddenly.

Hi,

Only thing I can think of is either some debris like PTFE tape has
blocked the cold inlet, or a lump of loose scale has got stuck in the
valve.

With gradual scale buildup I'd expect it to have increasing trouble
holding the set temperature,

cheers,
Pete.