Are my myson power extra valves closing too quickly?

[Steelbird]

Hi, we've been having a problem with our motorised valves. Every time the heating turns off there a number of loud bangs as if the water is hitting the valve too quickly which is then sending a shockwave through the pipes.

Would this be faulty valves in that they are closing too quickly or is there another issue I should be looking into?

The valves themselves are 2 ft above the boiler. It is a riello 40 oil boiler.

We have one for the radiators and one for the hot water. Both make this noise regardless of which on is on and then turned off.

Also the hot water is heating even when the valve for it is turned off but I'm not sure if that has any correlation to the noise we are hearing.

Any help would be appreciated. I have seen threads before about the valves potentially being put on the wrong way round but how would I check this? Is there an easy way to check which way the water should be flowing?

Many thanks

 

[ShaunCorbs]

You should have an auto bypass that opens when the valve shuts

 

[John.g]

To check for correct direction, feel the two boiler pipes, identify the hottest one, if the M.valves are installed on this (flow) pipe then the arrows on the valves should be pointing away from the boiler, if installed on the cooler (return) pipe then arrows should be pointing into the boiler.