Collection:Ultrasonic Flow Meters For HVAC

An ultrasonic flow meter measures clean water and water/glycol in closed-loop heating and cooling systems, such as building HVAC. These are Belimo sensors, which measure by transit time: the meter sends sound pulses with and against the flow, and the difference in travel time gives the flow rate. Nothing turns or projects into the bore, so there is no wear and no obstruction. They also measure the water temperature, so a control system can work out heating and cooling energy.

Selecting an ultrasonic meter

The meters cover small to large pipe and connect to a building automation or control system:

• Connection: a threaded BSPP-G connection on the smaller sizes, or a flange on the larger ones, sized to the pipe.
• Output: a 0 to 10 V signal that wires straight into a controller.
• Power: a 24 V AC/DC supply, the standard control voltage in HVAC panels.

Built-in compensation keeps the reading accurate as the water/glycol mix and temperature change. The meter is meant for clean water and water/glycol, not for oils, chemicals, or aggressive liquids. The sensor has a fixed cable and no display, because the control system shows and uses the reading, not the pipe.

Frequently asked questions

Why ultrasonic for heating and cooling water?

It has no moving parts and nothing in the bore, so it does not wear or restrict the flow, and it needs little maintenance over a long service life. The transit-time method measures clean water and water/glycol without anything blocking the pipe.

How does it connect to a control system?

The 0 to 10 V output wires into a building automation or control system, which receives the flow and the water temperature. From the two together, the controller works out the heating or cooling energy used. The meter runs on the 24 V AC/DC supply common to HVAC panels.

Does it show a reading at the pipe?

No. The Belimo sensor has no display and a fixed cable; it sends its signal to the control system, which shows and logs the value. It is made for a plant room or riser, sending its signal back, rather than for a reading at the pipe.