ULKA Pump repair kit Ball Valve and Viton O-Ring For: EX5, EP5, EP5GW If your coffee machines pump pressure dropped over time and flow is low or pump just makes buzzing sound but no flow. You should carefully take your pump apart and check: 1. If scale or debris is stuck inside you need to clean it, descale in acid solution. 2. Measure ball valve diameter if it's smaller than 4mm you need to replace it because it can stuck inside. 3. Check piston o-ring if it feels hard and stiff you need to replace it because it can't hold water pressure anymore. 4. Check if springs are not broken. If it's broken you better buy a new pump or a new spring if available.  5. After replacement and full assembly, prime your pump from air left inside by connecting syringe 50-100ml filled with water.  Repair Kit Contains: 1PC FKM O-Ring ~5x1.8mm 1PC Glass Ball Valve 4mm in diameter 1 euro coin not included, only as size comparison :) Airmail Priority Shipping No returns accepted If you have any questions, please don't hesitate to ask.