Hydraulic balancing of a heating system

In short: Hydraulic balancing adjusts a hot-water heating system so that every radiator or heating circuit receives exactly the amount of water it needs for its room. As a result, all rooms warm up evenly and the system runs more economically.

In more detail: Heating water always takes the path of least resistance. Without balancing, radiators close to the pump get too much water and those far away too little, which is often compensated for by a higher pump setting or flow temperature.

In detail

• Typical signs: Some radiators never get properly warm while others are hot straight away; valves rush, whistle or gurgle; some rooms take a long time to warm up.
• Room-by-room calculation: The basis is a calculation of each room’s heat load, i.e. how much heat it loses in cold weather. This gives the required water flow for each radiator.
• Setting the valves: The heating engineer sets the calculated flow on pre-settable thermostatic valves or return valves. Old valves without a pre-setting option are usually replaced for this.
• Pump and flow temperature: The pump output and heating curve are then adjusted. Afterwards a lower pump setting and a lower flow temperature are often enough.
• Simplified and detailed methods: There is a simplified method using estimated values and a more precise method with room-by-room heat load calculation. The more precise method generally gives better results.
• Benefits: Even warmth, less noise, lower pump electricity consumption and usually less heating energy too. How much you save depends heavily on the building and its starting condition.
• Heat pumps and condensing boilers: Low return temperatures are particularly important for heat pumps and condensing boilers. Balancing helps to achieve them.
• Documentation and funding: The balancing should be documented in writing. It is a requirement for many funding schemes for heating upgrades; check the current conditions beforehand.
• Context: Balancing complements other measures such as replacing the pump and well-adjusted thermostats (heizungspumpe-tauschen-und-optimieren, heizkoerperthermostate-und-smarte-heizungssteuerung, heizkosten-senken-und-richtig-heizen).