Vents Air duct heater NK 100 (Ø100MM/1.6KW/IP40)

An electric duct heater for round 100 mm ducting, 1.6 kW across two 0.8 kW elements. Requires a minimum airflow of 120 m³/h.

The NK 100 heats the air you supply, inside the duct, before it enters your space. There is one condition that outranks all the others, and it is also the first line in the specifications.

Minimum airflow is not a guideline

This heater lists 120 m³/h as its minimum airflow. That figure does not describe how well it performs, but the condition under which it may operate at all.

A heating element in a duct is cooled by the air passing over it. That air carries the heat into the room; that is the entire purpose. Too little air passing, and the heat stays at the element and the temperature there climbs well beyond what was intended.

So this heater must never run without your fan running. Not briefly, not as a test, and not with a closed damper further along the duct. It should be wired so it cannot switch on while the fan is off, and so it switches off before the fan stops. Vents documents a connection using a time-delay relay for exactly this, letting the fan run on after the heating is switched off.

The unit carries thermal protection, and the wiring diagrams show that one of those protections must be reset by hand after tripping. That is a safety net, not an operating mode: if it trips, that is a signal something is wrong with your airflow, and you find out what before resetting.

Connection

This is fixed wiring at 7 amps on 230 volts. Have the connection made by a qualified electrician and follow the Vents manual, which is authoritative for the wiring and the protection.

The heater is mounted inside the duct itself, horizontally or vertically, in ducting of the same diameter as the heater.

Technical Specifications:

• Duct: 100 mm
• Power: 1.6 kW, two 0.8 kW elements
• Minimum airflow: 120 m³/h
• Current: 7 A
• Supply: 230 V / 50 Hz, single phase
• Ingress protection: IP40
• Weight: 2.9 kg
• Mounting: in the duct, horizontal or vertical

Frequently asked questions

Can it run without the fan going?
No, never. The airflow removes the heat; without air the temperature at the element climbs.

What does that 120 m³/h mean?
It is the minimum airflow at which the heater may operate, not a performance figure.

The protection has tripped. Now what?
Find out why your airflow failed before resetting. A trip is a signal, not normal operation.

Can I wire it myself?
Have a qualified electrician do it. This is fixed wiring carrying a substantial load.