Viessmann Vitodens 200-W WB2B35 Problem

Viessmann Vitodens 200 W WB2B35 Condensing Boiler Running Fine Then Entering Non-heating State - No Fault codes. Skip to 6:40 to see in failure mode. Boiler will run normally for anywhere from a few minutes to an hour. A few days ago the boiler ran normally for about 8 hours so the problem appears to be getting worse. Boiler has been in service about 5 years. Boiler has not been fully functional for over a week now. However, I can&find a Viessmann technician to service my boiler.