Completed annual maintenance on on gas high efficiency Boiler, pulled combustion chamber and vacuumed, brushed with CLR solution and cleaned with fresh water, inspected fiberglass insulation which looks good, igniter looked good, flame sensor clean, did clean both, put system back together, boiler pressure normal, no leaks from any water components, boiler got up to temperature, took delta t reading for first floor air handler which had a difference of 53 degrees, checked antifreeze levels which were good, performed combustion and efficiency test which everything looked normal, system operational and working.