Vokera 35E

[CliffJP]

Hi, I have a Vokera 35E which makes a banging noise like kettling. This starts when the heating comes on and is very loud. If I then switch off the demand for heating and switch on the hot water demand for a couple of minutes the noise stops. If I then switch off the hot water demand and switch on the heating demand the heating works fine until the next time the heating switches on from cold, then the whole sequence starts again. Any ideas why switching the water demand on and then off again stops the kettling effect ??

 

[John.g]

Do you have a S plan with a number of 2 port valves or a Y (or W) plan with one 3 port mid position valve or diverter valve?

 

[Scott_D]

Are your TRVS open?
Got water/pressure in the system?

 

[CliffJP]

Are your TRVS open?
Got water/pressure in the system?

Yes, water in the system and no air. Heating works fine everywhere when working (all radiators).

 

[CliffJP]

Do you have a S plan with a number of 2 port valves or a Y (or W) plan with one 3 port mid position valve or diverter valve?

Hi John, it is a "Y" plan system. It also has an extra pump in addition to the one within the boiler. In total there are 18 radiators. Thanks - Cliff.

 

[John.g]

Is this pump starting immediately on a CH call and what make/model/mode& setting is it running on?

 

[CliffJP]

Thanks for the help.
I've stripped out the heat exchanger and removed the scale. after refitting it's now working perfectly - Regards - Cliff.