water hammer? boiler overheating?

[wilroda]

Hi
Can someone explain what water hammer is ....our boiler makes occasional odd and loud noises like a car door slamming...could this be water hammer or the boiler overheating?

Could anyone direct me as to the cause of this.....the boiler is rather old, a Myson Apollo

Thanks in advance

 

[corgiman]

I would say the the three port valve is causing this here problem

have a listen to it as it moves from ch to hw only and see

 

[Slugbabydotcom]

Firstly you dont get water hammer on boilers so after giving due respect to the preceding post what you have is probably boiler noise.

Apollo's often are a bit noisy but this can sometimes be relieved a little by opening the balancing valve slightly but possibly at the cost of some of your rads not getting hot.

A powerflush can sometimes help but that is quite expensive. Seeing as these are a bit out of date now you would be better saving up for a new boiler

A cheaper alternative is to add some fernox or other make of boiler noise reducer / silencer. Just a chemical that you add to the system. [Assuming your system has a seperate feed and expansion tank]