Valliant Boiler Hissing Repeatedly

dan83590 · 29 Nov 2010

Hi, we have a valliant boiler that has recently started to hiss about every second.

The boiler's stat has always been set to full (position 9). When up to temperature the flames go out and the hissing stops. When hot the pressure gauge rises to 1.5bar.

Any ideas why this is?

Here is a picture of our ancient boiler...

Wangerman · 29 Nov 2010

dan83590 said:
Hi, we have a valliant boiler that has recently started to hiss about every second.

The boiler's stat has always been set to full (position 9). When up to temperature the flames go out and the hissing stops. When hot the pressure gauge rises to 1.5bar.

Any ideas why this is?

Here is a picture of our ancient boiler...

Can't help you out with your problem but you have the same boiler as I do in my new house

clf-gas · 29 Nov 2010

You have low pressure in your system.

The white needle in the first dial should be level with the red needle, when heating off and rads cold. Rising to 1.8 or 2 bar when heating hot.

Top up via filling loop under the boiler.

dan83590 · 29 Nov 2010

I have raised the pressure. It is still hissing every second or so. What should i try next? It's started doing this noise over the last couple of weeks. Everything seems to be working CH and HW still feel as hot as before.

ReganAndCarter · 29 Nov 2010

Can't help with your problem.

However, if you need a brilliant Vaillant engineer in Bristol, I can recommend the one we used to use. He's an ex-vaillant engineer, and been doing Vaillant repairs for years.

Alan Wakley

07816 320226 or 07743 377128

Hope this isn't classed as advertising. I have no connection with him.

Beerlover · 30 Nov 2010

Get a RGI to check the boiler, The gas pressures drift up on these, also the problem may be electronic and the boiler may not be modulating,

Both above DIY I'm afraid.

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Valliant Boiler Hissing Repeatedly

dan83590

Wangerman

clf-gas

dan83590

ReganAndCarter

Beerlover

DIYnot Local

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