The efficiency of a modulating control system depends on the controllability of the hydronic system. The circuit characteristic is one important measure of the hydronic design quality and thereby the controllability.

The circuit characteristic is the relationship the control signal (u) to a control valve and the resulting thermal power (P) from the unit.

The steeper the circuit characteristic curve, the higher the risk of control instability.  A more linear shape will result in greater control, and therefore, greater comfort.

How can we ensure a linear curve?

• By using a control valve with the correct valve characteristic adapted to the terminal characteristic and a good linear actuator.
• A hydronic design and balancing that minimise the impact of valve authority.

Why balance small terminal units?
What control?
Circuit characteristic
TA Solutions
Which solution to use?
Proven control