Ceramic tap cartridge - how tight should the nut be?

[dummer]

Hi. I have just purchased (online) a ‘Crosswater side lever mono kitchen mixer tap’. when fitted, it leaked slowly from where the side lever attaches to the spindle of the ceramic cartridge. After getting nowhere fast with the supplier I purchased a replacement cartridge. I had tried fiddling with the original cartridge by tightening the brass retaining nut and loosening it but it kept leaking whatever I did.
my question is….how tight should I tighten the brass retaining nut? The cartridge has three ‘o’ rings fitted on the face which abuts to the ports in the body of the tap. I don’t want to overtighten and squash the ‘o’ rings but want to make sure it’s tight enough.
thanks.

 

[opps]

How old is it? You say that you have just purchased it. I recommend that you ignore the reseller and contact Crosswater. Then ask for a refund for the cartridge. If new, you seem to have a faulty product (the base may not, for example, be ground properly).

I am guessing that crosswater will bounce you back to the reseller with regards to the cost of the replacement valve, Perhaps threaten to lodge a case against the reseller with the small claims court.

I am not a plumber though.

 

[dummer]

Thanks Opps. The replacement cartridge that I bought was only £4.60 so I’m not bothered about the cost. It’s just how tight to tighten the brass nut which holds the cartridge in place.