DN40 Ultrasonic Heat Meters (1 1/2”)

DN40 is the largest threaded heat meter size in our range; it is used on high-flow lines such as building sub-distribution circuits, commercial units and small boiler rooms.

Where Threaded Meters Give Way to Flanged

DN40 corresponds to a 1 1/2-inch pipe size. The technical data for the Honeywell and Novus Digitermo DN40 give a nominal flow rate (Qn) of 10 m³/h, a body length of 200 mm and a 2” connection thread. The next size in our range, DN50, is flanged and has a nominal flow rate of 15 m³/h. If your design flow rate is around 10 m³/h, choose between DN40 and DN50 based on pressure loss and the connection type in the system. Check your local regulations for periodic re-verification requirements; see also our re-verification and calibration page.

Models in This Size

• Novus Digitermo DTL-DN40 – Qn 10 m³/h, 200 mm, heating/cooling
• Minol Zenner C5 IUF DN40 – built-in wired M-Bus, 3 pulse inputs
• Calmet PM02-DN40 – built-in wired M-Bus
• CEM CM-HR DN40 – built-in wired M-Bus
• Honeywell DN40 – Qn 10 m³/h, 200 mm, heating only

Other sizes: DN15 · DN20 · DN25 · DN32 · Large diameter (DN50–DN300) · DN20 mechanical

Frequently Asked Questions

How many inches is a DN40 heat meter?

DN40 corresponds to a 1 1/2-inch pipe size; the models on our site have a 2” connection thread.

Are there threaded heat meters larger than DN40?

In our range, models up to DN40 are threaded, while DN50 and larger models are flanged. Larger sizes are listed in the large-diameter heat meter category.