How tight should I seat the non return valve on the Bialaddin 300 X ? I’m having sealing problems, I’m using the correct washer and little one that fits in the cup, the original spring but just cannot get an airtight seal. I’ve tried just a snug fit to so tight the washer deforms but no luck. I’ve even stretched the spring a bit which didn’t help so replaced that with another original I had lying around. All advice appreciated.
Those NVRs can be problematic, sometimes you just need to take it out and re-assemble it. Check that there isn’t the remains of an old washer in there and try a drop of oil on the washers to help with lubrication and initial seating. If the main (larger) washer is okay it should only need nipping up to seal.
I have re-sealed a good number of these but I had one recently I just gave up with. I ended up buying a band new one from Julian Lands. When I get a moment I will return to it - anyway I will end up with a spare which is no bad thing. What I did notice is that the pips in my service kits were not cut straight preventing the seal sitting as flush as it could.. I suspect this is the answer..
Thanks for the help. I’ve studied the pictures of the new ones on the bay and have noticed the little pip sits just proud slightly protruding from the cup. I’ll try a tiny bit of solder in the bottom of the cup to lift the pip slightly so it is making contact instead of the edges of the brass cup. Ive also noticed that the length of the upper part of the valve part varies by about 1/8”. That’s the end you screw into the bottom of the tube, definitely have two of different lengths here.
