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Crown Boiler Company KSZ120

144,000 BTU, Steam Boiler, 84.5% Efficiency, Oil Fired


The KSZ series boiler is a cast iron oil-fired low pressure steam boiler designed for use in closed heating systems. This boiler must be vented by natural draft into a lined masonry or metal chimney, or Type L vent. An adequate supply of air for combustion, ventilation and dilution of flue gases must be available in the boiler room. This boiler has connections for use with an indirect domestic water heater. The KSZ series boilers are not designed for use in process or other “open” steam systems.

Please read this Important Safety Notice

Standard Features
  • Rugged wet base cast iron heat exchanger
  • Swing-open burner door for easy service
  • Choice of three oil burners
  • Attractive split jacket easily removed for servicing
  • Insulated to save energy
  • Fully assembled, ready for installation
  • Factory tested control system
  • Three physical sizes with nine firing rates
  • Combustion chamber with a ceramic fiber target wall with blanket
  • Drain valve
  • Draft regulator
  • Oil solenoid valve
  • Burner twist disconnect plug
  • Twelve year warranty on the cast iron steam heat exchanger
  • Pressure gauge
  • ASME pop safety valve
  • 3” top supply tapping for optimum steam quality
  • Low water cutoff
  • Optional side-mounted tankless coil for domestic hot water
  • Equipped with connections to add a CROWN indirect domestic water heater
D.O.E. Heating Capacity

Heat output, measured in BTUs, of a boiler before the allowances for piping and pick-up.

D.O.E. Heating Capacity
144000 BTU
IBR Net Rating Steam
108000 BTU
Burner Capacity
1.20 GPH
Efficiency (% AFUE)

The percentage of energy converted into output by the unit. The remaining percentage is lost during the conversion process. The higher the efficiency, the lower the operational cost.

Efficiency (% AFUE)
84.5 %
Min. Recommended Chimney Size
8 x 8 x 15 Dia(in) Ht(ft)
Flue Size
8 inches
Supply Piping Connection
3 inches
Return Piping Connection
1 1/2 inches
Product Weight
810 lbs
Meets CSA Standards

Canadian Standards Association

Meets CSA Standards
24 1/2 Inches
26 1/2 Inches
31 1/2 Inches
Cast Iron Sections Warranty
12 Years
Parts Warranty
1 Years