Kettling or water hammer?

[hairyjon]

Hi folks. The boiler is a Morco FEB24E lpg fitted in a 2006 ABI Caravan running central heating and hot water to kitchen and shower.
I have been having problems with noise every time the kitchen sink hot water tap is turned off and this is now affecting the shower.
I had been advised by a qualified heating engineer that this was due to 'kettling'.
The heat exchanger and various other components in the boiler have been replaced to the tune of £500 but no improvement.
I am sure that the problem is water hammer and not kettling.
Has anyone got any ideas what might be causing the problem?
A while ago I noticed a leak on the caravan water supply stop valve and tightened the gland nut and this seemed to improve things for a while.
Thanks,
Hairyjon.

 

[hairyjon]

Hi folks.
Has anyone seen this posted from my mobile!
Any help would be appreciated.
Thanks,
Hairyjon.

 

[Servotech]

If the kitchen tap is of the quarter turn lever type I would swop it or change the cartridge.
Water hammer is very common fault with these taps when they are worn.

Water hammer noise tends to be a single "Bump bang" when the tap is turned off; whilst a kettling noise is more of a prolonged "pssst pssst bump bang psst pop pop bang pssst" (quite scary) type of noise.
servotech

 

[hairyjon]

Hi Servotech. Thanks for your reply. The kitchen tap is type that is lifted to turn on and then turn right or left to adjust temperature.
The noise comes from the boiler and can only be described as: eeeeeeeurghghghfumph that lasts for about 5 seconds when the tap is turned off. There is also a whining noise when the tap is open. This also happens when the shower is being used. I wonder if air is getting into the system somewhere.
Jon.