ALpha CB28 - making hissing noise when turned off/on

z3usx · 8 Apr 2008

Hi

My Alpha CB28 boiler has started to make a hissing noise when it is cold and also when it is on. Just wondered should i be worried as my boiler cover with alpha will not start until 28 days.

Any advice is much appreciated. Thanks

gas4you · 9 Apr 2008

Is the system pressurised to just over 1 Bar cold? If not hissing could be the auto air vent.

Are you having to constantly top up the pressure?

z3usx · 9 Apr 2008

Pressure is 2.5 bar when its cold as well as hot - the boiler also started to drip water after a bit when turning it on - it has done it a few times before.

However the hissing has now gone. Any pointers on stopping it from dripping?

Thanks

gas4you · 9 Apr 2008

Drop the pressure to 1.2 Bar cold.

z3usx · 9 Apr 2008

Would i do that by bleeding the radiators? If so how much do i release and from one or all radiators? or any other method of reducing the pressure.

Thanks

ChrisR · 9 Apr 2008

First make sure the filling loop is CLosed - or better, disconnected.
Drop pressure by bleeding rads, or letting water out from a drain cock.

See the FAQ'a on pressure problems, for background.

z3usx · 10 Apr 2008

Hi

I managed to drop the pressure on the bioler like you said and i found the filling loop was and has been slightly open since i moved in the flat. Whacked the heating on full from cold and tested the hot water, works perfectly.

Cheers

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

ALpha CB28 - making hissing noise when turned off/on

Similar threads