Slight leak on boiler

[sxturbo]

The 24x16 washer will be fine, it possible this plastic thing has been put in as a bodge, the thickness 3mm could be what's made it fail.

As Harry has suggested try the compressed cardboard for a temporary fix. Lightly coat the cardboard with silicone sealant (fernox lsx works well with plumbing and heating)

24x18x1.5 seem to be the most popular size and will work perfectly fine. If you do need the 3mm thickness you can always double the washer, not ideal, but being fibre material it shouldn't be an issue

 

[Pro100]

Wahay, eventually sorted (i think, still testing )

All the plumbers merchants were closed so had to go to screwfix. They didn't have a like for like replacement so i had to end up buying a fibre washers set for 18.99 as one of the washers was roughly the same size.

Got home and smeared a slight coating of LSX on the fibre washer and tightened everything up, so far so good (touch wood)

Thanks everyone who helped, much appreciated