Property is a bungalow and until a replacement combi boiler was installed we never had waterhammer.
The mains comes in at the front of the bungalow and the combi boiler is right at the back, so long runs of pipes especially for hot water.
The previous boiler's pipework made spaghetti junction look neat so the installer cut it all out and started again. Apart from the combi boiler the only alterations were:
1) In-line stop valve to the cold water feeding the boiler and the remainder of the utility room (two sinks, shower, outdoor tap, washing machine)
2) In-line scale remover
It feels as if the hammer is worst when the washing machine solenoids kick in (it's cold water only) or if one of the cold water taps in the utility room are used.
I'm confused; from the descriptions I've read it seems as if cushioning air has been let out, though some logic tells me that it is air in the system that is the problem.
Ideas on how to approach returning the system to it's former quiet operation.