Grinding Vaillant Turbomax boiler

[Mrast]

Hi all,

Last few days my Turbomax Pro has started making a grinding noise when either DHW or CH is turned on and the boiler is getting up to temp.

I have narrowed this down to either the pump (newly replaced 6 months ago) or the fan as these are the only 2 moving parts that would make a continued grinding noise.

When the boiler has "warmed" up (or should i say the water) after about 3/4 minutes the sound goes away and you dont hear it again until the boiler is shut down and has to start up from cold again (often next day)

The sound kicks in after about 30 seconds of the CH being turned on and starts when luke warm water first appears out the tap when DHW turned on.

When the demand for DHW is turned off while the grinding is happening the noise stops straight away (leading me to think its the pump rather than the fan, as the fan continues for a few seconds/minutes depending on how long the boiler has been operating for)

So advice:

Do i replace the pump again to see if that is the problem (still got the old pump that wasnt knackered but was "failing" according to the guy who serviced in in Oct of 2011. I can do this myself no problem. Only drawback is my draining system/filling/bleeding etc it will take me a good half a day and if its not the pump a waste of my time.

Do i spray some WD40 on the fan to see if thats failing (as the grinding noise does sound like a failed fan in a PC/Laptop (my profession)

To throw a spanner in the works the sound has only started to happen since Wales and West have been digging up and replacing all gas pipes in the road and to houses on my street.

Thanks for any advice in advance.

(Pressure happily sits at 1.5bar and rises to approx 2.3 when heating on)
(Pump was brand new when fitted only 6 months ago.)
(No air in rads)
(The tyre cap on the pump is open by about 1 turn)

 

[mountainman]

The diverter valve can also make a grinding noise when opening/closing.
Try putting a long screwdriver against the pump or diverter when the noise is happening and put your ear to the screwdriver handle.
This will amplify the noise and will usually pinpoint the source.

 

[Mrast]

Thanks for suggestion.

I will try the screwdriver technique tonight.

I have uploaded a 1 minute sound recording of my boiler when i turn the hot water on (sound is same when CH turned on)

It can be downloaded from http://dl.dropbox.com/u/895609/Voice 001.zip
mp3 file is in the zipped folder.

There is a click at 13 seconds
On 22 seconds the "grinding begins" at this point my phone is in front of the pump
On 39 seconds i move the phone to the top of the boiler casing just above where the fan unit is.

Hopefully this helps understand my rambling trying to describe the problem

Kind Regards

 

[Mrast]

The diverter valve can also make a grinding noise when opening/closing.
Try putting a long screwdriver against the pump or diverter when the noise is happening and put your ear to the screwdriver handle.
This will amplify the noise and will usually pinpoint the source.

Did this and put the screwdriver against the metal casing of the fan.

The noise got amplified through the screwdriver head when the griding happened, and when it stopped the noise was just a gentle humming and buzzing sound.

So i think i shall start hunting for a replacement fan..

 

[mountainman]

Don't forget that to replace the fan legally you need to use a GSR engineer.