Serpentine belt coming off

[Flibzy]

Hi, I’m new to the forum and need some advice. 
 I have a 2005 a3 2.0tdi bkd engine code. I’ve recently replaced my serpentine belt and tensioner and everything was fine for a few days. However I noticed that the tick over was slightly high, around 1100 revs/minute. After around two weeks the serpentine belt has shredded again. 
 Does anyone know what causes this?

 Thanks 

[Steve Q]

It sounds like a faulty/poor quality component used. Or incorrect fitting. My dad had this with an old land rover, Cambelt had to be changed sorry after it had been done as it wasn't fitted right. 

[Stevey Y]

19 hours ago, Flibzy said:

Hi, I’m new to the forum and need some advice. 
 I have a 2005 a3 2.0tdi bkd engine code. I’ve recently replaced my serpentine belt and tensioner and everything was fine for a few days. However I noticed that the tick over was slightly high, around 1100 revs/minute. After around two weeks the serpentine belt has shredded again. 
 Does anyone know what causes this?

 Thanks 

Hi most likely a seized idler pulley or alternator clutch pulley.

Steve.

[cliffcoggin]

Probably a seized pulley has damaged the belt as Steve mentioned, but worth considering pulley or tensioner misalignment.

I don't see that any of those things would affect the idle speed.

[Flibzy]

On 6/25/2022 at 4:30 PM, Stevey Y said:

Hi most likely a seized idler pulley or alternator clutch pulley.

Steve.

Thanks mate. I’ll have a look at that 👍🏻