Worcester Greenstar 28i junior - Possible Water Hammer?

[sooey]

If the boiler continues firing for 30 seconds after you've turned off the tap it's no wonder it's banging.

 

[swa110w]

Really? Should it switch on and off with the hot tap then?

It's always done that, I just assumed it was the way it was meant to be.

Thing is, this noise occurs when the boiler comes on (and goes off) in the middle of the night (to pre-heat water, I believe), when no taps have been opened.

 

[sooey]

Really? Should it switch on and off with the hot tap then?

Yes, you need to get it looked at. In the meantime switch off the preheat.

 

[spatel]

Hi there. My greenstar 28i jnr boiler has exactly the same problem. Did you ever solve the problem?

 

[swa110w]

Hi there. My greenstar 28i jnr boiler has exactly the same problem. Did you ever solve the problem?

Sadly not. I contacted Worcester Bosch about it and this was their response:

The sound could be occurring due to water coming up against the non-return valve at the end of demand.

This can be resolved by having a mini expansion vessel or shock arrestor fitted on the incoming water supply to the boiler as close to the boiler as is practicable. This will allow an expansion of water at that point rather than coming up against a valve.

A suitable part would be part number 7-716-192-105.

From what I gather, that is going to be quite expensive, so we're going to hold off until we get it serviced later in the year.

Annoying, isn't it?

 

[spatel]

Thanks for your reply. I have yet to obtain a solution from several accredited worcester approved plumbing companies who have inspected the fault.