Electric duct and air heaters place resistance-heating elements within a moving air stream.
Electric duct and air heaters place resistance-heating elements within a moving air stream. The heated air may support building ventilation, drying or an industrial process. Heater performance depends on both total airflow and its distribution across the element bank. A duct with adequate average flow can still contain poorly swept regions. Selection therefore includes the inlet condition, duct transitions, nearby obstructions and the minimum permitted operating flow. This is an air-side product: a heater installed in an HVAC water circuit belongs to a different application and requires a different design review.
Define the minimum airflow, inlet condition and required temperature rise, then match the heater face, element arrangement and controls to the duct and operating sequence. Electrical power is only one part of that specification.
For adding heat to an HVAC air stream. Define outside-air conditions, supply-air targets and the ventilation system's turndown range, together with the building control sequence and available electrical capacity.
Enquire about this configurationFor heating air used by production equipment. Start with inlet temperature, composition and continuous duty, then review the element environment and the required temperature at the process entry.
Enquire about this configurationFor processes where air temperature is part of a moisture-management sequence. Explain the airflow route, recirculation, exhaust and material being treated so heater selection fits the whole process.
Enquire about this configurationFor air-heating duties associated with power-station ash handling. Clarify whether the heater sees clean upstream air or a contaminated stream; dust exposure cannot be inferred from the application name.
Enquire about this configurationDiscuss the distribution of elements across the useful airflow area. A larger duct dimension does not automatically mean every part of the heater receives adequate cooling air.
Use a duct drawing to review the frame, mounting position and maintenance access. Include insulation thickness and the space needed to remove the assembly without disturbing unrelated equipment.
Compare staged and modulated heat with the response needed by the process. The discussion should include the minimum stable load and the way the fan changes speed.
Define airflow proving and overtemperature protection separately from the normal temperature loop. Agree which conditions prevent energization and which faults require investigation before restarting.
Share these details with your inquiry. Product ratings and operating limits are confirmed for the selected configuration.
| What to specify | Unit / format | Selection guidance |
|---|---|---|
| Air volume and minimum flow | m³/h | Give normal, minimum and maximum flow, plus the reference temperature and pressure for the figures. |
| Inlet and outlet temperatures | °C | Specify the coldest inlet, hottest inlet and required outlet condition at each operating case. |
| Duct and heater opening | mm | Provide internal dimensions, airflow direction, orientation and the proposed insertion or connection arrangement. |
| Pressure allowance | Pa | State available fan pressure and the permitted pressure drop across the heating assembly. |
| Air composition | process description | Identify humidity, particulate loading, corrosive constituents and any flammable vapor or combustible dust. |
| Electrical supply | V / Hz / phase | Provide supply details and the available capacity for the required heating stages or modulation. |
| Control interface | signal / sequence | Describe temperature demand, fan status, flow proving, fault indication and the supervisory control interface. |
| Installation envelope | mm / °C | Show service access, adjacent duct fittings and the ambient condition around the terminal enclosure. |
Give normal, minimum and maximum flow, plus the reference temperature and pressure for the figures.
Specify the coldest inlet, hottest inlet and required outlet condition at each operating case.
Provide internal dimensions, airflow direction, orientation and the proposed insertion or connection arrangement.
State available fan pressure and the permitted pressure drop across the heating assembly.
Identify humidity, particulate loading, corrosive constituents and any flammable vapor or combustible dust.
Provide supply details and the available capacity for the required heating stages or modulation.
Describe temperature demand, fan status, flow proving, fault indication and the supervisory control interface.
Show service access, adjacent duct fittings and the ambient condition around the terminal enclosure.
For bringing an air stream toward the required supply condition. Include seasonal inlet changes and reduced ventilation rates, since the heating requirement and element cooling change together.
For supplying heated process air to a suitable drying or curing system. Provide the material and exhaust conditions; a heater alone does not establish a complete drying process.
For heating an air stream associated with ash-handling equipment. Use the plant process diagram to define the actual air quality, pressure conditions and control responsibility at the heater.
List airflow and inlet temperature together for startup, normal duty and reduced-load operation. This avoids selecting the electrical input from a single condition that does not represent the whole process.
Review elbows, dampers, transitions and filters near the proposed position. Specify a suitable flow profile at the heater face, with access to inspect and maintain the upstream components.
Document the relationship between the fan, heat demand, flow proving and temperature limits. Use the final equipment instructions to establish the installation and shutdown sequence.
Send your application details, drawing and planned quantity. We can review the configuration and the information needed for a quotation.
These references explain heating principles. Confirm the ratings, approvals and operating limits of the proposed VELHEAT configuration in its own documentation.
General duct-heating relationship between airflow, sheath temperature and independent temperature cutouts; no catalog ratings adopted.
Airflow proving as an interlock for duct-heater operation.
