Not quite "pipe hammer" but close?

[chalkywhite]

Hi, we had a new boiler system fitted with its pressurised setup that does away with a header tank, replaced with a red sphere shaped bottle thing. We get regular loud moaning from pipes when running cold or hot taps at high flow. The pipes vibrate in the airing cupboard, so it's a bit like water hammer i guess.

The moaning can go from a few seconds to 10 seconds, and just afterwards we hear a rushing water noise, like the water is finally getting through the system somewhere. We put up with it for about 14 months, but it seems to be getting more regular now, almost every time we run the taps anywhere in the house.

I assume it's an airlock somewhere that clears after the few seconds?

We have to regularly keep an eye on a pressure valve in our airing cupboard, and we are able to turn two taps to let water into the pressurised system. I think that's how the plumber put it!

We had a problem with water hammer in a downstairs loo, but i fitted an in-line isolation valve to the cistern, and have adjusted the flow so that it fills slower, but we get little to no hammer noise anymore.

Help very much appreciated.

Cheers, Tony

 

[Space cat]

I would expect mains pressure water to blow out an airlock. If you turn on the highest cold tap in the house, does it eventually splutter?

Having said that, I remember a cold water airlock problem coming up on the plumbing forum (which is where you should have posted). In that case, the OP had altered some pipework in the loft and trapped a column of air in the supply to a cold tap in the room below. Thinking along those lines brings me to a tentative cause for your problem.

Your rising main would once have gone up to a header tank. If it then continued down to your other taps, you would have an inverted loop where air could collect. (Mains water contains dissolved air.) Of course this air escaped every time the tank's ball valve opened - but your tank has gone!

PS: That pressure meter is for your heating circuit which is - or should be - completely isolated from the hot water supply.

 

[doitall]

The installer may have left dead legs where he altered the pipes which trap air as well.

Unfortunately you should have got them back straight away.

 

[chalkywhite]

Thanks for your input guys.

The plumber came out, sat in the loft whilst i ran the bath taps, and the minute the "moaning" started, he lifted the cold water tank ball valve, and the noise stopped immediately.

I was given the option on a normal valve or an equilibrium valve, i went for the latter, just to try to eradicate all hammer noises in future.

Water flow is now much much quieter, and no moaning

Cheers, Tony