Water hammer due to zone valve closing

[DP]

If Honeywell valve bangs, change it for one that has a paddle instead of ball mechanism

 

[FiremanT]

They wont have been fitted the wrong way round , they were probably the right way round, then when your installer fitted the new boiler they swapped the flow and return around as it was easier for them so now the zone valves are the wrong way round

Possibly, but the pump must have been reversed.
A pic would be useful

 

[u33446z]

typical diy install fook up

Well, no, installed by a local experienced tradesman. But it’s not very clever, is it?

 

[u33446z]

Thanks all for your suggestions. The zone valves have indeed been fitted the wrong way round

Installer returned today to switch round the two zone valves. Now no water hammer!

 

[ianmcd]

just hope that your TRVs dont start rattling now

 

[u33446z]

System is silent!