For what its worth this is what I have done with mine! I have discarded the expensive unreliable supplementary air valve.I have replaced it with a 3/8in ball valve ($5 from the local hardware).This I have placed discreetly under the dash and I operate it like a choke in a carby car.It operates with a gentle hissing sound as it breathes alcohol enriched air from the cabin .No more problems
Woody
P S It also greatly simplifies the plumbing.
I had a similar problem with parts ordered from Citroworld which turned out to be a freight issue. When I managed to get hold of Geert he was more than helpful in getting the problem fixed. I'd stick with it.I'm still waiting for Citroworld !!! they took my money, sent me a part that doesn't work and now they don't respond to my emails. Can I recommend them - keep well away!