Our vaillant thermomax combi boiler has started making a loud howling
moaning noise when heating water. Its fine on the central heating. It
had been making a slight kettling type noise for a while when heating
water, and occasionally faults with F22 ("dry") even though the
pressure is fine.
Any ideas ?
Thanks,
Simon.

On Mar 9, 10:28*pm, sm_jamieson wrote:
Our vaillant thermomax combi boiler has started making a loud howling
moaning noise when heating water. Its fine on the central heating. It
had been making a slight kettling type noise for a while when heating
water, and occasionally faults with F22 ("dry") even though the
pressure is fine.
Any ideas ?
Thanks,
Simon.

Now its starting making what sounds like a dodgy bearings fan noise
when on
the central heating.
Simon.

On Mar 9, 10:37*pm, sm_jamieson wrote:
On Mar 9, 10:28*pm, sm_jamieson wrote:

Our vaillant thermomax combi boiler has started making a loud howling
moaning noise when heating water. Its fine on the central heating. It
had been making a slight kettling type noise for a while when heating
water, and occasionally faults with F22 ("dry") even though the
pressure is fine.
Any ideas ?
Thanks,
Simon.

Now its starting making what sounds like a dodgy bearings fan noise
when on
the central heating.
Simon.

Noise stops when boiler is turned off.
Noise stops if hot water flow is very slow.
Something in the secondary heat exchanger vibrating ? Its hard to tell
where the vibration
is coming from with the cover off. Could be diverter valve.
Whole thing needs cleaning out I'm sure.
Simon.

On Mar 9, 11:24*pm, sm_jamieson wrote:
On Mar 9, 10:37*pm, sm_jamieson wrote:

On Mar 9, 10:28*pm, sm_jamieson wrote:

Our vaillant thermomax combi boiler has started making a loud howling
moaning noise when heating water. Its fine on the central heating. It
had been making a slight kettling type noise for a while when heating
water, and occasionally faults with F22 ("dry") even though the
pressure is fine.
Any ideas ?
Thanks,
Simon.

Now its starting making what sounds like a dodgy bearings fan noise
when on
the central heating.
Simon.

Noise stops when boiler is turned off.
Noise stops if hot water flow is very slow.
Something in the secondary heat exchanger vibrating ? Its hard to tell
where the vibration
is coming from with the cover off. Could be diverter valve.
Whole thing needs cleaning out I'm sure.
Simon.

Oh, and it also does it when the "stay warm" feature is activating -
presumably passing some hot water
through the heat exchanger even though there is now flow through the
other side of it.
Simon.

On Wed, 09 Mar 2011 23:24:43 -0000, sm_jamieson
wrote:

Something in the secondary heat exchanger vibrating ? Its hard to tell
where the vibration is coming from with the cover off.

Our Baxi Megaflo exhibited what sounds like a very similar fault. In our
case the vibration wasn't caused by anything mechanical, it was combustion
instability at certain degrees of 'modulation' (so like yours it was very
dependent on the demand). Took a long time to fix, but eventually
succumbed to the engineer adjusting the mixture at the 'low' end of the
modulation range.

Richard.
http://www.rtrussell.co.uk/

On Thu, 10 Mar 2011 18:00:56 -0000, Richard Russell wrote:

On Wed, 09 Mar 2011 23:24:43 -0000, sm_jamieson
wrote:

Something in the secondary heat exchanger vibrating ? Its hard to tell
where the vibration is coming from with the cover off.

Our Baxi Megaflo exhibited what sounds like a very similar fault. In our
case the vibration wasn't caused by anything mechanical, it was combustion
instability at certain degrees of 'modulation' (so like yours it was very
dependent on the demand). Took a long time to fix, but eventually
succumbed to the engineer adjusting the mixture at the 'low' end of the
modulation range.

Richard.
http://www.rtrussell.co.uk/

Can you remember how that was done, please? My Vaillant vibrates a bit
between 40C and 50C if the 'power' is set down (on this system, 50 - 55% is
enough) and I would like to stop it.
--
Peter.
The gods will stay away
whilst religions hold sway

On Thu, 10 Mar 2011 18:34:58 -0000, PeterC
wrote:

Can you remember how that was done, please? My Vaillant vibrates a bit
between 40C and 50C if the 'power' is set down (on this system, 50 - 55%
is enough) and I would like to stop it.

It involved the use of a flue gas analyzer, so not a DIY job. I think the
service engineer was following the manufacturer's instructions, but he
said he didn't normally bother checking the 'low' end of the modulation
range as it rarely needs adjustment.

Richard.
http://www.rtrussell.co.uk/

On Mar 10, 6:00*pm, "Richard Russell" wrote:
On Wed, 09 Mar 2011 23:24:43 -0000, sm_jamieson *
wrote:

Something in the secondary heat exchanger vibrating ? Its hard to tell
where the vibration is coming from with the cover off.

Our Baxi Megaflo exhibited what sounds like a very similar fault. *In our *
case the vibration wasn't caused by anything mechanical, it was combustion *
instability at certain degrees of 'modulation' (so like yours it was very *
dependent on the demand). *Took a long time to fix, but eventually *
succumbed to the engineer adjusting the mixture at the 'low' end of the *
modulation range.

Richard.http://www.rtrussell.co.uk/

Was it under warrantee ? I get the impression some gas fitters would
charge diagnosis by the hour
and you could end up paying more that the boiler is worth to get it
fixed.
Gas chap thought it might be the pump (at least 100 quid), but there
are several issues I think.
Boiler is around 10 years old and we are thinking maybe time to get a
new one.

Also, it may just be crud in various places but to take the whole
boiler apart and clean the pump,
heat exchangers etc and flush the whole system would be a right pain.
And no hot water whilst
you are doing it. No good getting a new boiler and it crudding up
again in no time.
I would have thought there would be filters to stop stuff getting into
the secondary heat exchanger
but it is squelching as if there is something (perhaps air ?) in
there.

A bit of a rant, but some things just seem more hassle than they
should be !

Simon.

On Thu, 10 Mar 2011 22:53:49 -0000, sm_jamieson
wrote:

Was it under warrantee ? I get the impression some gas fitters would
charge diagnosis by the hour

When I said "a long time" I meant it took about three visits from a
service engineer before he hit upon what was necessary to fix it. They
were routine annual services so it didn't cost much more than we would
have been paying anyway.

Richard.
http://www.rtrussell.co.uk/

On Mar 10, 11:33*pm, "Richard Russell" wrote:
On Thu, 10 Mar 2011 22:53:49 -0000, sm_jamieson *
wrote:

Was it under warrantee ? I get the impression some gas fitters would
charge diagnosis by the hour

When I said "a long time" I meant it took about three visits from a *
service engineer before he hit upon what was necessary to fix it. *They *
were routine annual services so it didn't cost much more than we would *
have been paying anyway.


Ah maybe thats where I'm going wrong. No service visits ever in its
lifetime !
How much do you pay for a service visit ?
Was this a regular arrrangement that might warrant a discount ?
Was it "scheme" like British Gas boilersafe or whatever it's called.
If he needed spare parts to try and fix it and they turned out not to
be needed, did / would you still have to pay for them ?
Simon.

On Fri, 11 Mar 2011 08:57:27 -0000, sm_jamieson
wrote:

How much do you pay for a service visit ?

Our most recent service was about GBP 75, from a local family firm. I
think spare parts are extra, if needed, but our system is fairly new
(house built in 2007) so none have been required as yet.

Richard.
http://www.rtrussell.co.uk/

On Thu, 10 Mar 2011 22:34:13 -0000, Richard Russell wrote:

On Thu, 10 Mar 2011 18:34:58 -0000, PeterC
wrote:

Can you remember how that was done, please? My Vaillant vibrates a bit
between 40C and 50C if the 'power' is set down (on this system, 50 - 55%
is enough) and I would like to stop it.

It involved the use of a flue gas analyzer, so not a DIY job. I think the
service engineer was following the manufacturer's instructions, but he
said he didn't normally bother checking the 'low' end of the modulation
range as it rarely needs adjustment.

Richard.
http://www.rtrussell.co.uk/

Oh dear, s I need to find a competent boilerdroid.

Thanks.
--
Peter.
The gods will stay away
whilst religions hold sway