Combi Boiler Sounds

[escapee]

Hi All

We have recently had installed a Glowworm Flexicom 30 CXi, this is the first combi boiler we have ever had installed and all appears to be well but there is a strange sound I would like to query.

When we turn the cold water tap on (anywhere in the house), you can hear the boiler whirl up, its not the same sound as when it kicks in with the hot water, but you can hear it stirring as if priming itself, then when you switch the cold water off the boiler makes a sound almost similar to someone blowing lightly into a trombone or someone dragging a chair across the floor. Is this noise a characteristic of boilers and could it be 'cured'? The boiler has been installed around 3 weeks.

I hope someone could put my mind at ease, I don't want to disturb the original installer if its nothing to worry about though.

Thank you in advance for any feedback!
escapee

 

[scatmanjohn]

I would be having someone back to have a look at it.

 

[Agile]

It sounds as if you may have a "dead leg". This is a length of hot water pipe with air in so that the boiler is brought on when a cold tap is operated.

This most often happens when a hot tank system is replaced by a combi. Sometimes its because the installer was lazy and did not disconnect old pipework. Other times it would have been difficult and is reasonable to leave.

Sometimes this cures itself as the air dissolves.

Other times a non return valve after the boiler is needed to be added.

Tony

 

[escapee]

Thanks Agile

Could this cause a problem over time if not rectified? The sound emitted is not noisy just strange.

As far as I am aware the installer removed everything except the header tanks in the loft, which as you say were not practical as they were much larger than the loft hatch and also were not causing any obstruction.

I 'think' it may even do this when the next door neighbours turn their cold water supply on, could that be possible??

 

[Softus]

Has the filling loop been left in place with its service valve open?