Arrived onsite to diagnose a no-heat issue on a Viessmann propane boiler. The boiler was running and up to temperature, calling for domestic hot water. I cycled power and the system called for heat. When we ran the hot water, it called correctly, but the boiler never switched back to heat afterward. I checked the temperature sensor on the water heater and did not find any issues. They had a new aquastat that came with the water heater, so I installed it. Verified operation and confirmed the boiler is now switching properly between heat and hot water. The system is functioning correctly at this time.
