When hot water taps turned on there's an intermittent noise from the boiler.
Gas eng thinks it's water hammer.
He's adjusted service valves on hot taps and tried different settings on main stop tap to flat.
It's still happening but so much.
Plenty of hot water being delivered.
Have fitted new LH pcb.
A few months ago a new bathroom was fitted?
Any ideas?
Central heating working fine and no noise from boiler.

steve, March 2016