Quick Product Details: KN4

Condensing, High Efficiency: 400,000 BTUs

Featuring large Delta Ts and fully modulating 400,000 BTUs, the KN4 cast iron boiler is the ideal condensing boiler unit to address the challenges of the growing radiant heat and snow melt markets, as well as other new construction and retrofit boiler applications.

KN4's small vent size also allows the utilization of existing vent work as a chase for new equipment in retrofit applications, and its small footprint makes incorporating its power into new constructions simple as ever. With 92.7% thermal efficiency at full input and 99% combustion efficiency at minimum input (5:1 turndown), the KN4 is a high efficiency condensing gas-fired boiler option. And the durable cast iron engineering behind the KN Series, when coupled with HeatNet 3.0 boiler control technology, makes for optimal fuel utilization and increased boiler performance.

  Gas Pressure Voltage Flow
Nom 7" W.C. 120 V 1ph 60hz
Min 2" W.C. 7.2 GPM
Max 14" W.C. 72 GPM
  Temperature Rise Flue Length
Min 20°F 6 Equiv. Ft.
Max 100°F 100 Equiv. Ft.
  Air Inlet Length Water Volume
Nom 5.6 Gals
Min 0 Equiv. Ft.  
Max 100 Equiv. Ft.  
  Flue Diameter Current
Nom 5 Amps
  Cv, @ 1 psid Boiler
  40 GPM 11 HP
  Input Output
  399 MBH 369 MBH
  Fuel Type ASME Design Data Max
Fuel Nat. Gas/LP 100PSI +250°F
  Height Length
  51 29/32" 22"
  Width Weight*
  35 7/16" 780 lbs
*Weight is reflective of "Shipping Weight"