Droning noise - boiler

[dg123]

I have a Worcester-Bosch HE+35 Greenstar, it was fitted Sept 04. When the HW is used there is a VERY loud droning noise from the boiler. It doesn\\\'t do this when the CH is activated. The boiler is set to do a \\\'hot water release\\\' at 05:00 each day and this is usually when the noise is greatest (I\\\'m not sure what this process is as the manual is less than expansive) - I have had the installers back but, of course, it didn\\\'t make the noise. Any ideas - serious responses please, I need to know if there are any safety issues here. W-B have been less than helpful.

 

[Agile]

I dont know what you mean by a "hot water release"!

In any case I dont expect you will get a boiler engineer to attend at 0500hrs!

Why not set this "release" to 11.30 am so that the engineer can see it then?

Tony Glazier

 

[dg123]

I don't know what it means either! It is the original setting on the boiler and as the manual is not comprehensive I did not want to change any settings. It is not the only time it happens though, it is usually each time the hot water tap is turned on - except for when we had the plumber back to listen to it! The noise disappears if the HW tap is closed, then opened again gradually. I have never had central heating of any kind so the world of boilers is new to me.

 

[doitall]

is the problem associated with one particular tap or all of them

 

[dg123]

All, although that sounds a bit grand as we have only two HW taps - one in the kitchen and one in the bathroom.

 

[andywolfie]

It sounds as though the co2 levels are set incorrectly,only a problem on hw as it then fires at maximum rate,the installers should of set it up and time of installation with an analyser,cant set it up any other way,hw release from 5.00 just means hw is available from that time just like an ordinary timer coming on,just sounds posh!!you have a great boiler there,just needs some fine tuning.

 

[dg123]

Thanks very much for the reply AW, (and for the reassurance re the boiler) I will contact the installer again and ask for the check to be done.

 

[ollski]

Is it a foghorn type noise, I have come across a few where the butterfly type valve in the air intake of tha fan has been missing since installation.

 

[dg123]

No, it's more like a digeridoo(!) but at a higher pitch. I suppose it is similar to air being forced down metal ducting. It didn't make the noise immediately but a few months after installation it started. It is very loud - I can hear it from at least 25 yards away.

 

[gasgeezer]

the noise you describe is almost certain to be combustion ratio if it is in warrenty worcester may set it for you

 

[ollski]

All factory set though on the greenstar, I will bet the valve is missing. Just underneath the fan on the black plastic bit it says something like twist and undo. If you undo it and have a look there should be a round valve with 2 flaps on to control the air ...have a look.

 

[andywolfie]

they may be factory set but site conditions vary,the inlet gas working pressure needs to be at least 18.5mbar,if this cant be achieved then you will never get the correct levels,as for the valve you are on about,it's actually a diaphragm it doesn't control the air,it's there to stop condensate running down into the gas valve,the air/gas flow is controlled just above the gas valve,this problem on this boiler is all about getting those correct C02 levels,thats all it is.

 

[easygoin]

Just having the same problem - with my HE42 greenstar .... called tech support (lol) at Bosch and they thought it was almost always to do with the CO2 levels (or the flue setup and commissioning ) as these go out of setting in transport etc he said. Probably down to 1mm worth of a turn on the CO2 valve he said..... so good to see similar answer here.

Also seen a number of installers who don't check expansion vessel pressure - why can't they just test and set this accordingly ?? - the boilers tend to come with 2.5 bar by default, and bear in mind that it should be 0.5-1bar, for the sake of a tyre gauge ...lol - nothing to do with the above problem though as far as I know.

Thanks for the great help here

PS -its a foghorn and diggery doo type sound and if you go outside ...my god it's loud - only on hot water especially if tap turned on half way and not fully on .... wakes up the neighbourhood - no Christmas cards from the neighbours any more now .. he he

 

[AQ6000]

Also seen a number of installers who don't check expansion vessel pressure - why can't they just test and set this accordingly ?? - the boilers tend to come with 2.5 bar by default, and bear in mind that it should be 0.5-1bar, for the sake of a tyre gauge ...lol - nothing to do with the above problem though as far as I know.

Thanks for the great help here

PS -its a foghorn and diggery doo type sound and if you go outside ...my god it's loud - only on hot water especially if tap turned on half way and not fully on .... wakes up the neighbourhood - no Christmas cards from the neighbours any more now .. he he[/quote]

Never having experienced this I'm a bit reluctant to comment but might it not be the water limiter on the cold water inlet? Just a arrow shot into the air.. If you have high cold water inlet pressure, turn it down a little and see if this helps. W-B probably would have suggested this if it had occured before but it's a simple and cheap thing to eliminate.

 

[dg123]

Just having the same problem - with my HE42 greenstar .... called tech support (lol) at Bosch and they thought it was almost always to do with the CO2 levels (or the flue setup and commissioning ) as these go out of setting in transport etc he said. Probably down to 1mm worth of a turn on the CO2 valve he said..... so good to see similar answer here.

Also seen a number of installers who don't check expansion vessel pressure - why can't they just test and set this accordingly ?? - the boilers tend to come with 2.5 bar by default, and bear in mind that it should be 0.5-1bar, for the sake of a tyre gauge ...lol - nothing to do with the above problem though as far as I know.

Thanks for the great help here

PS -its a foghorn and diggery doo type sound and if you go outside ...my god it's loud - only on hot water especially if tap turned on half way and not fully on .... wakes up the neighbourhood - no Christmas cards from the neighbours any more now .. he he

Easygoin, I can empathise re the noise levels, I'm sure my neighbours, being aged around the eighty mark, thought that war had broken out again due the noise from the boiler.

I've been working away so I've had a bit of a delay in contacting W-B. I phoned W-B on Thursday (28/07), the engineer was on site the next day so a big plus to them on that.

Would you believe it, with the engineer on site the boiler did not make the noise! Luckily he didn't just walk away, he checked the gas pressure, water pressure (no problems with either), re-set the CO2 levels as they were out and also changed the fan. So far no noise but I will keep an eye (ear) on it. Looks like you were correct andywolfie.