Hello Boffs, tried this once before, but need more help!
12 yo Worcester 280. Running through mixer taps with shower hose.
Will run perfectly for 10-15 mins or so, then water goes cold for maybe a minute or so then slowly comes back to temp? There is no other water draw off during this process.
The h/w and C/h thermistors have been changed, but it's still happening.
Any ideas please? I've had 2 blokes who are stumped??

What happens to the boiler when this happens? Does the boiler continue burning normally while the water goes cold?

Does it do it at other taps or just the mixer?

Is it a thermostatic mixer?