We also had the same problem TWICE with a Lunar Quasar EB (2005 model). We had a replacement fitted in 2008 when one failed, and the replacement failed in 2011. Despite very carefully telling the dealer the part number on the existing one, they looked at the Truma website and said it was 10mm. When a fitter arrived to fit it, he said it should have been the 8mm version - another long trip to the dealer and another wait for a fitter. I would never buy a Truma regulator by choice - I believe there are now regulators from alternative suppliers that work!
