Removed the existing Ultimate boiler and installed a new Pure Pro oil boiler. The existing supply and return manifolds were retained and connected to the new system using updated piping. Installed a new expansion tank and Spirovent air eliminator to improve system performance and reliability. Replaced the water feeder, backflow preventer, and two circulator pumps. Connected the new boiler to the existing domestic hot water piping, adding new purge valves, a thermostatic mixing valve, and a scale filter. Installed a new switching relay, reused the existing common wires for the Nest thermostats, and added a dedicated service switch. Installed new smoke pipe and connected it to the existing chimney with a draft damper. Reconnected the existing oil line using a new flexible connection and Firomatic safety valve. The mixing valve was set to position “3” on the boiler high limit to maintain approximately 115°F at all faucets. Performed a full system startup, verifying the operation of al
