rattling noise from a vaillant ecotec plus 837

[moogwai]

Been to a vaillant ecotec plus 837 today that has a rattleing noise coming from somewhere inside the boiler....i think it may be the pump but cant be definate. Not really familiar with working on these and wondered if anyone out there has a method for finding annoying rattleing noises or if there is a common fault with this boiler or is it a case of removing parts till i find something?
Boiler is working fine but customer is saying that the noise is getting gradually worse, gas rate and working pressures are fine as is the fg ratio.
cheers guys.

 

[stevetheplumber]

fan or pump shouldnt be hard to tell which it is

 

[moogwai]

fan or pump shouldnt be hard to tell which it is

fitting a new pump on saturday....and i beleive i have to change the whole block and can't getaway with just changing the head as they have apparantly modified it.

 

[washer]

Ive replaced a couple of these pumps, they were both making a right racket. vailliant have modified them to a grundfos, and not to painful to change.

 

[moogwai]

Ive replaced a couple of these pumps, they were both making a right racket. vailliant have modified them to a grundfos, and not to painful to change.

yeah thats what the bloke in curzon said......but i though that vaillant always used grundfos pumps!! must just be this particular boiler. cheers mate.

 

[stevetheplumber]

vailants had a brief flirtation with wilo then back to grunfos