Worcester 24I junior banging noise for 10 minutes

[SparksterOK]

My Worcester 24i Junior Combi makes a banging noise when the Central Heating is turned on. This lasts for approx 10 Minutes.
I can instantly stop the banging by opening a hot tap for a few seconds, after closing tap the banging comes back within 15 seconds. I repeat this procedure about 6 times and the boiler runs and there is no more noise.
I am confused as as far as I was aware the Central Heating and Hot water are different systems - The boiler pressure appears OK, and the only work I have had done recently is thermostatic valve on one of the radiators.
Any feedback would be appreciated.

 

[twgas]

Try adjusting the new trv next time it bangs.

 

[theheatinghelper]

check that the trv`s installed are reverse flow, if they are not, this can cause the banging on the heating system!