Oil-Fired Water Boiler, 98MBH, 87% AFUE, Series 3

Williamson Thermo‑flo OWT‑3‑T‑S3‑W – 98 MBH Cast‑Iron Oil‑Fired Chimney‑Vent Water Boiler with Tankless Coil

The OWT‑3‑T‑S3‑W is a factory-assembled, three-section oil-fired water boiler rated at 98 MBH input. With an 87 % AFUE efficiency, it delivers approximately 75 MBH net heating output. The boiler includes a Taco‑007 circulator and a pre-installed tankless domestic hot water coil. Chimney venting is standard, with rear flue connection and optional top flue kit :contentReference[oaicite:1]{index=1}.

???? Key Contractor Features Efficiency & Capacity 98 MBH input, 75 MBH net output, 87 % AFUE unitedsupplyusa.com +11 williamson-thermoflo.com +11 oswaldsupply.com +11 Construction & Components Cast‑iron sections with integrated air separator High-efficiency oil burner with PSC motor, solid-state ignitor, and solenoid valve unitedsupplyusa.com +9 oswaldsupply.com +9 williamson-thermoflo.com +9 Heavy-gauge insulated steel jacket and plug-in wiring harness assets.unilogcorp.com +9 williamson-thermoflo.com +9 24hr.supply +9 Service Access & Controls Swing-away burner door and top access cleanout for rapid service Includes low-limit control, probe low-water cutoff, temperature limit control, and thermal pre-purge sequence ebirdsall.com +15 williamson-thermoflo.com +15 oswaldsupply.com +15 Chimney Vent Setup Rear flue collar standard; optional top-flue kit available Designed for 8″×8″ rectangular or 6″ round chimney ebirdsall.com +4 afsupply.com +4 afsupply.com +4 ebirdsall.com +14 williamson-thermoflo.com +14 oswaldsupply.com +14 ???? Technical Summary Specification Value Input 98,000 BTU/hr (0.70 GPH oil) Net Heating Output 75 MBH (DOE) AFUE 87 % Sections 3 cast‑iron Vent Rear chimney; optional top kit Controls LWCO, temp limit, pre-purge, circulator Jacket Insulated steel; service access ???? Installation & Application Notes Commissioning: Factory-tested and ready for field hookup; install with proper draft according to OWT manual (−0.01" to −0.02" w.c.) 24hr.supply +3 generalplumbingsupply.net +3 williamson-thermoflo.com +3 afsupply.com +6 sidharvey.com +6 oswaldsupply.com +6 williamson-thermoflo.com +3 oswaldsupply.com +3 oswaldsupply.com +3 sidharvey.com +5 ebirdsall.com +5 ebirdsall.com +5 Ventilation: Verify sound chimney sizing and clearances per NFPA 31 and 211 ebirdsall.com +1 ebirdsall.com +1 Domestic Hot Water: Built-in coil enables ~3 GPM DHW at 200°F boiler water temperature 24hr.supply +1 energystar.gov +1 Serviceability: Burner and coil accessible via front and top panels, simplifying maintenance cycles ???? Contractor Summary The OWT-3‑T‑S3‑W is a compact, high-efficiency oil boiler with integrated domestic hot water capability. Its cast-iron durability, factory-mounted controls, and easy service features make it a reliable choice for both new installations and retrofits in residential settings. Compliance with ENERGY STAR and inclusion of a tankless coil and circulator streamline setup for streamlined mechanical systems.