My Nomad 2 has worked flawlessly for years, up until now. I performed the maintenance as per the manual a year or so back and hadn't used it since. I went to top up a rifle today and it won't build pressure beyond 50 bar or so. The LED read out varies between 18 to 20 and you can hear that it's working. I check the fittings on the line and can't detect any leaks and the external fittings are snug. I'm guessing a dried out o-ring or somewhere?