Indirect Fired

Providing clean and tempered makeup air to meet your application needs. The push-through design ensures that combustion fumes will not enter the fresh air stream.

The Modular Indirect Fired Bent Tube Heater is designed to deliver clean air into an indoor environment. Units are designed for indoor or outdoor installation, and can use either Natural or LP gas. The standard unit includes a blower module and the IBT heater module that is approved in the United States and Canada. The unit is listed to the ANSI Z83.8-2006 and CSA 2.6-2006 standards. Each furnace has a 6:1 Turndown Ratio and a maximum Turndown of 28:1 for the entire unit, depending on total required BTU Capacity and number of furnaces in the unit.

Every unit is programmed to start in high fire mode to ensure consistent light-off and is equipped with an electronic, Vernier-type fully-modulating control system. The duct furnaces are all type-409 stainless steel, and certified by the American Gas Association and approved by the Canadian Gas Association. Each model utilizes at least one, but not more than two, modulating stage(s) and between zero and two additional ON/OFF stages depending on the required heat output. In addition, the speed of its power-vent blower on the modulating furnace(s) is varied as the gas flow changes; thereby maintaining a constant 81% combustion efficiency over the entire gas-firing range of the unit.



Bent Tube In-Shot Style Furnace with Type 409 Stainless Steel Heat Exchanger
81% Constant Efficiency over Entire Gas Firing Range
6:1 Turndown per Furnace, 28:1 Max
Full Electronic Vernier-type Modulation
Forced High Fire Start
Variable Speed Power-vent Motor
Discharge, Space or Building Automation System (BAS) Temperature Control
Isolated and Insulated Electrical Controls Vestibule
Natural Gas or Liquid Propane Applications
Inlet and Manifold Gas Pressure Indicating Gauges
Electronic Push Button adjustment for the Modulating Gas Valve
High Temperature Limit Switch
Flame Rollout Switch with Manual Reset
LED Indicators for Troubleshooting
Economizer Inlet Air Thermostat
Advanced Human Machine Interface (HMI) Controls


Electrical Cabinet LED Lights
5:1 Turndown for Propane (LP) per Furnace. 23:1 Max
Up Discharge
Motorized Intake Damper
Remote Control Panel
High and Low Gas Pressure Switch
Mixing Box
Variable Air Volume (VAV) Controls
Double Wall Construction
Blower on Delay (Heat Exchanger Pre-heat)
Freeze-stat Option
Fire-stat Option
Convenience Outlet
Extended Drop
Single Point Electrical Connection
Control Cabinet Heater
Dirty Filter Airflow Switch
Auxiliary Starters
Roof Curbs
Indoor Hanging Cradle
DDC Control capability for BACnet MS/TP, LonWorks, Johnson N2, and Modbus Protocol

Available Options

1,000 - 17,000 CFM