Noisy hissing radiators

newfoundglory

Hi all.

Just moved into a house which has had a new central heating system and boiler (Ideal 30) fitted.

Annoyingly, the radiators make loads of hissing noise (all of them) and i'm not sure why.

When the heating went off this morning, and boiler displaying status 0, the hissing noise continued for about another 5-10 mins until the boiler had stopped completely.

Any ideas what might be wrong?

Thanks

bris

What 30 boiler is it, a system boiler? It sounds like it's overheating and the pump over run is dumping heat back into the radiators by way of a bypass.


What ever it is the radiators shouldn't be hissing, you will need to get the experts in.

newfoundglory

Its an Ideal classic 30 combi boiler.

The hissing sounds like its coming from the bleed value at the top, which i think are manual ones. But its hard to determine.

Niv

newfoundglory wrote: »

Its an Ideal classic 30 combi boiler.

The hissing sounds like its coming from the bleed value at the top, which i think are manual ones. But its hard to determine.

If the bleed valves are hissing as opposed to leaking water it sounds like you need to bleed your rads!


Could it be a water leak somewhere in the system if all rads are suddenly low ?

bris

Ah I see them very rarely so never thought about it but you will have those auto air valves that don't require bleeding. They hiss to expel air from the system automatically.
In your case they may just have required bleeding so expelled the air which emptied your system so will need topped up again. You need to put pressure back into your system if that's what's shown 0.


P.s it will happen until all air is expelled if the pressure dropped to 0 before the rads were fully topped up.

newfoundglory

So there was one radiator which was not working at all, while all the rest were hissing.

After watching YouTube videos, the cause of the one radiator not working was the lockshield valve which was almost closed. Opened using some tools I had which made that radiator work.

The hissing has now drastically reduced or stopped, but the rest of the radiators have changed.

One radiator went cold and I had to subsequently bleed manually to get it working again - quite a bit of air came out.

Any tips for balancing? And any idea as to what the hissing was which has now stopped?