Responded to no-heat call on 12-year-old Burnham boiler. Diagnosed issue with thermostat wiring - customer had incorrectly placed R wire on Rc terminal instead of R terminal after recent thermostat replacement. Corrected wiring configuration, verified system operation, and confirmed boiler fired properly. Outdoor reset was active, limiting maximum temperature. Inspected all components with no additional issues found. Provided customer education on system operation.
