cistern bottom fill valve no longer sealing - B3300-M

[mockers]

I've seen a number of similar threads related to my problem...so it may be a known common issue...anyway, after a year of perfect use, the fill valve (WDI B3300-M-) in my cistern is no longer fully stopping the water inlet when the float lifts...the valve appears to work and the inlet water is reduced, but there is a continual slight hiss of air (I think) and the water rises in the cistern until inevitably if starts overflowing into the pan. I've removed the top of the filler & checked/wiped the seals and checked all fittings for damage. I live in a hard water area so am thinking there's some problem with limescale...but there's nothing obvious!

Its a simple mechanism with only one moving part (float/cap) so I cant but help thinking its wear and tear of the seals...but after only a year!

Your ideas/thoughts are welcome...

Mockers

 

[wiggers]

I would just replace with a new fluidmaster pro45b fill valve
Good luck

 

[Paulplumb]

Replace the washer if available.

 

[mockers]

Hi wiggers...yes, I could just replace the valve...but that wouldn't tell me why its stopped working or why it's failed. I'm loath to fork out money for a year old part! I'm sure you would complain if your fuel pump failed on your car after a year!

Paulplumb...there are two washers and they both look fine & I've washed them both...again as above, are washers expected to be a yearly replacement?

Is there a recent (i.e. over the last say 10 years) trend where specific parts are just wearing out? Or have cistern components become just another set of throwaway items?

 

[Paulplumb]

Hi mockers, changed dozens of these modern washers. Can't say any of the knackered ones looked any different to the new one replacing it. The new washers generally work. If it doesn't it's a new valve. At the end of the day a new washer is pennies and a new valve is a tenner or so. I have had brand new washers fail. Just one of those things. Can't find the valve you have but the washer you'll want to replace might look something like this.

modern

Or this

older style

 

[mockers]

Hi paulplumb,I recognise the washers in the lower picture...except it has a hole to take the central fixed pin from the top valve section. I'll see if I can get a replacement set...

 

[stevetheplumber]

i dont even bother with washers screwfix do a valve for about £7 not worth trying

 

[mockers]

Hi stevetheplumber, whilst I agree a replacement valve is a (relative) simple replacement job...I like to understand why things fail before I resort to just replacing stuff...old fashioned that way I suppose! I also want to understand why some parts only last a year!

If I was in the trade, I'd probably do exactly as you say as it's less hassle for you and the client, but I'm not...I'd rather repair the fault whilst getting some experience in how the mechanism operates and its possible flaws.

P.S. if I can repair this Ill be the first one down to Screwfix to buy a £7 one :smilewinkgrin:

 

[Dotty]

Sometimes parts just fail. We tend to accept it and move on.

 

[gassafe]

Fit a better quality valve & it will probs last longer. Fluidmaster as suggested are good...