Odd noise from boiler.

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Hi there,

Boiler: Vaillant ecoTEC+ 937.

Problem: When someone opens the hot water tap fully fairly quickly an odd vibrating noise can be heard from the boiler for a few seconds. Hot water is delivered properly and at the normal temperature and flow rate.

Settings: DHW set at 50C with the storage tanks on.

History: Never had problems with the actual boiler. Boiler fitted in October 2008.

Experiment: Reset the boiler but to no avail, tried different taps and the problem is present with all hot water taps.


Research: Boiler noise seems to be attributed to kettling, fan noise and thermal expansion....god knows what else.

Current situation: We will call Vaillant as the boiler is under guarantee but I am just curious to find out what you think is causing the noise.

Can anyone tell me what is causing the noise?
 
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without hearing it its difficult to say. what kind of vibration noise?
 
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A different possibility would be a combustion "shuddering noise" but in that case it would be most obvious outside listening to the flue.

I have encountered that when the meter is close to the boiler and the boiler "pulls" on the meter regulator.

Tony
 
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Right just been to video it, rubbish quality taken with my phone camera and it was dark.




Frightened me this time.
 
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er.....thats a really odd noise. im clueless :confused:

i tell you what it sounds like, If you have an unvented cylinder with an external exp vessel, and the dynamic pressure is low and static high, you can get a vibration in the pipe as the pressure equalises. but that doesn't fit into your system so im baffled. you haven't got an accumulator have you?
 
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well its a possibility I guess, but i've not come across it yet on one of these and its usually from day dot as opposed to starting up.

is it every tap or just one? also you can try altering any stopcocks in the water line to see if its something like that.
 
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The noise will only be heard if you open the tap quickly, most people open the tap pretty quickly so we noticed the noise.

The kitchen tap is limited to about 4l/pm to prevent splashing, this tap does not make the boiler create the terrible noise.
 
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could be similar to the problem I've had with UVs then. The solution is to measure the dynamic pressure, then set the EV pressure to match. Be a first I've heard of it on a store combi mind you.
 
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Could this problem have been caused by the EV losing pressure?

Is it a good idea to turn the tanks off and see if the problem persists?
 
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sounds mechanical, do you have a one way valve fitted to the cold feed under the boiler? or could be the sudden release of pressure in the pipework making one of the pipes under the boiler vibrated. does not sound like a combustion or kettling
 
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Yes a single check valve was eventually fitted because the dead leg could not be removed successfully.

But I'm wondering why the problem has only started now.

Thanks for all your input so far guys.
 
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sounds mechanical, do you have a one way valve fitted to the cold feed under the boiler? or could be the sudden release of pressure in the pipework making one of the pipes under the boiler vibrated. does not sound like a combustion or kettling

would have to agree with the above,i am not familar with this model,sounds like a bouncing non return valve.
 
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I agree it sounds mechanical.

David, try feeling each water in/out pipe while someone else opens a tap.

A dead leg comes to mind!

I would hold off calling Vaillant under the warrantee for the moment as it may well be external pipework rather than the boiler.

Tony
 

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