Is it just me, i seem to be struggling to pressurise Vapalux/Bialaddin lanterns fitted with the earlier small holed non return valves, even when cleaned, serviced and a new spring fitted, the later ones with larger holes i can use as normal but have to use the palm of my hand on the pump on the earlier ones, I might try and enlarge the entrance to the hole to see if that makes a difference.
So the non-return valve isn’t allowing air to pass without a lot of force applied to the pump. The diameter of the hole you’re referring to won’t be the problem. What you’ve described is that the NRV spring compression is too powerful. On occasion the spring is compressed too much because the pip seal is too long. Sometimes the spring is too long or the gauge of the wire it’s made of is too heavy. I’m saying this on the back of umpteen stove NRV’s serviced rather than Bialaddins specifically, but the balance (literally) of spring tension and its ability to compress effortlessly on a pump stroke and its capacity to make an effective seal on the pump pull stroke can be tricky to achieve sometimes. John
I normally have to stretch the original nrv springs on most Vapalux nrvs to get them to seal (my preferred pips being from the Fettlebox) i must admit i didn't try this one before stretching out of habit, after stretching it was difficult to pressurise so i replaced it with a new spring which seemed easier to compress than the original and the same springs have worked fine in the larger holed later nrv's, i will try another original length spring and see how it goes but it only ever seems to be on the older ones that i have the trouble with, Thanks for the input John.
I’m also trying to get one to work properly in a Bowlfire.. I’m not sure whether the pip is viton or nitrile? At first the pump rod was pistoning back so I have tried stretching the spring and it helped .. now only creeping slowly out :/ I have some cork so will try that but need to source a suitable wad punch or make one… I’ve compared nitrile with viton and viton is noticeably firmer.. the Willis & Bates style of nrv is similar to a lot of stove types as @presscall already mentioned so perhaps designed for cork or nitrile as viton was a later development? I’m sure this has already been much discussed… ps @MG when was the change in Willis @ Bates nrv size?
But if the spring’s too long the coils will be bunched up too much and the pressure required to compress it to enable the pip to unseat will increase dramatically, however easy to compress it seems out of the NRV barrel.
@podbros If you need any Vapalux Viton pips let me know as i have quite a few spare, I think possibly with the 320's but am happy to be corrected, @presscall I could be wrong but it seems as though the earlier nrv's had a thicker gauged wire spring which could be the problem, as i said its only those that i have had any issues with, i bought some new springs from a seller i buy from regularly and they work well in the later version but i must admit i never compared them against the earlier versions non stretched spring so you could be onto something there, the pips from the Fettlebox sit flush so it definitely looks to be a spring problem, i need to remove some nrv's from some spares lanterns up the garage to check them, i have serviced many Vapalux/Bialaddin lanterns but obviously i couldn't see the wood for the trees and just replaced the earlier nrv's with later ones
@MG I'm trying to fettle a 300x at the moment and when I opened the NRV I found the spring missing, and yet there was one or two coils still left around the brass pip holder stem. I am assuming that the spring just rusted away. Any idea where to order one. I've scoured the fettle box but cant find them listed. Paul
Ask at the base camp, otherwise break open all your biros and look at springs in them or get a new nrv. Good luck!
