Series 300Combination Boiler

Superior Boiler Series 300 Boiler for Combination Applications are efficient, ready-to-install packaged systems featuring a perfectly matched powerful and efficient burner and boiler combination.

Series 300 Combination Boiler can burn:
Natural Gas, Propane, #2 Oil, Dual Fuel

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Boiler Information

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  • UL Listed Gas Trains and Control Systems.
  • Choice of Power Burners.
  • Main and Auxiliary Gas Valves
  • Air Flow Switch
  • Main Manual Leak Test Valve
  • Bell and Gossett Circulating Pump
  • Second Bell and Gossett Pump for Coil
  • Honeywell Aquastat Relay
  • Automatic Low Water Cutoff
  • Honeywell Second High-Limit With Manual Reset.
  • Burner Control Relay.
  • High Visibility Operating Light.
  • Pressure/Temperature Gauge
  • Pressure Relief Valve
  • 1½” Diameter Firetubes of SA178-A Steel
  • Turbulators for Maximum Heat Transfer
  • Two Inches of Insulation With a Painted Steel Jacket.

All necessary boiler controls and secondary plumbing are in place and pre wired, and the vessels easily fit through a 30″ doorway, resulting in a very quick start-up. Each vessel contains a 60 foot copper coil through which the domestic hot water is circulated. This coil is surrounded by the hot boiler water, which transfers heat to the coil. Firing rates for the Series 300 Combination Boiler are available from 210,000 Btu/hr to 375,000 Btu/hr. However, many millions of Btu’s can be delivered by creating an efficient, fully modular system of up to 24 vessels operated by our computerized control panel.

Standard features include nationally known parts and controls that are available at most supply houses, allowing for quick and easy repair and maintenance, which can dramatically reduce down time.


Superior Boiler offers several options to customize your boiler. A job is not complete until the boiler has been properly equipped for the application.

  • Choice of burner manufacturers fired by natural gas, oil, propane, or dual fuel.
  • Fan-Damper relays
  • Barometric Dampers and Galvanized Tees
  • Clean-out openings and plugs
  • Microprocessor Control Panel for true lead-lag modulation
  • Factory built and customized primary mains and headers
  • Immersion Aquastats
  • Various Relief Valve sizes for different applications
  • Lifting Lugs
  • Rail Legs


The Series 300 Boiler is manufactured to exceed ASME Section IV standards and typically is used to provide supply temperatures from the coil of between 140-180°F, yet can accept extremely low return temperatures (below 100°F) without shocking the boiler.  The Space Heating side of this boiler can provide supply temperature up to 200°F, and return temperature can go as low as 140°F.  The temperature of the coil water is impacted by the temperature of the Space Heating side because the coil is immersed in that water. These vessels contain 37 vertical firetubes, each of which is 1½” diameter, each fitted with a high-efficiency turbulator for maximum heat transfer. The combustion chamber is fully water-backed, with burners that are UL listed. Vessel capacity is 35 gallons with a heating surface of 34 sq. ft. This boiler qualifies as a Category I gas appliance with industry standard controls wired to NEC specifications.


A well-made, heavy vessel is naturally a safer boiler. But Superior Boilers also have a firebox design that is completely backed by water, along with extra safety controls on the boiler that results in a very safe and secure package.

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Series 300 Combination Boiler Drawings

Series 300 Combination Boilers
Model #

Boiler Efficiencies

Series 300 Combination Boilers
Input (BTU/Hr)
Gross OutPut
Combustion Efficiency
GPM @ Riseº F
Pressure Drop Thru the Coil
7.3 @ 50º F
10.3 @ 50º F
12.9 @ 50º F

Boiler Dimensions

Series 300 Combination Boilers
Feature Dimension
Vessel Width 22″
Vessel Height 57.5″
Boiler Weight 800 lbs
Boiler Depth w/ Burner 40″
Gas Inlet Height 11″
Return Water Inlet Height 7″
Top of Vessel to Bottom Main 8″
Height to Lower/Upper Coil Openings 22″/46″
Height to Pump Flange 31″
Height to Space Heater Return 18.5″
Height Required at Installation 82″
Clearance to Rear of Boiler 18″
Clearance to Front of Boiler 48″
Clearance to Side of Boiler 18″
Clearance Between Boilers 3″
Height to 300 HEP Vent 51.5″