Strange issue here... (Yet another water hammer post I know but just looking for any other ideas) Water hammer when any tap (quarter turn) shower toilet etc turns off. Seems to be from under the bath / boxed in where the pipes come upstairs from the kitchen. I really don't want to cut a hole in the wall to see if they need clipped if I can help it. Also can't get under bath (new bathroom) again last resort. Tried a hammer arrestor (0.16L expansion vessel) on kitchen tap. Absolutely no difference. Turned stopcock down to just under halfway. Reduces flow drastically. Lowers hammer noise. Open any other tap in the house slightly. No hammer noise when closing. (But you can see the water pulsing through the other tap.) No dead legs that I'm aware of. No prv or meter. Combi boiler, no water tank. Water pressure at outside tap is 3.2bar. Any ideas before I open the walls would be much appreciated. TIA
Boiler pressure won’t affect your water hammer issue but it’s too high. Usually recommended to be around 1 bar.
Ah - makes more sense. That’s fine for mains pressure. Other than adding more shock arrestors I can’t offer any more advice if you don’t want to open up boxed pipework.
Work on the basis of try easy/accessible stuff 1st. After that I’m afraid time to bite the bullet. Bath panel should not be installed so that maintenance cannot be carried out, it will always at some time in the future. Lesson learnt
In most cases these days it points to a worn cartridge in what can be any tap in the property and not always were the noise appears to be coming from. A most popular worn cartridge is in the hot tap on the kitchen sink which can be indicated by it turning itself on when another tap in the property is opened.
Update: Decided to change old stopcock however we were unable to isolate the water outside. Water board came out and said they would need to dig it out and replace. 15 day wait for them to come back.