Old Vaillant Sine 18 Boiler whistling....

[antoine2000]

Hi

We have a 20+ year old boiler in the flat I bought last year. All has been well so far, but during the summer months when running hot water, the boiler began to whistle. The high pitch noise only happens with hot water, cold is OK.

I initially thought it was air, and today got the CH working for the first time and bled the Rads - but the noise is still there.

Apart from the annoying noise, everything seems to work OK - any clues, or is this the end for the Vaillant?

Thanks

 

[Agile]

These are still quite repairable for anyone who understands them.

Its difficult for me to guess but a first question is if the system pressure is correct at about 1.2 bar cold?

Tony

 

[antoine2000]

Pressure is fine - usually needs to be topped up once a month, but currently sitting pretty on 1 bar

 

[antoine2000]

Bizarre as it sounds, in the kitchen next to the boiler the noise only occurs when you are running 'warm' water - so cold and third degree burns hot is fine! weird!

 

[Agile]

There is fault on a type of flow rehgulator which can cause a whistle but I dont think your boiler has one of that kind.

Any rapid transition in a water flow part can cause a whistle.

Tony

 

[antoine2000]

easy to fix? by an expert that is?