What to do about noise in the heating system

Noise in the heating system is a well-known issue for installers. The noise can come from the pump, the pipes or the radiator thermostats – and it can be caused by either the mechanical parts of the system, air in the system or the water or fluid in the system. Since hydronic systems easily transport the noise, it can be difficult for the installer to know exactly where the noise is coming from.

In general, there are two main causes of noise in heating systems: wrong or incorrect commissioning and wrong dimensioning.  

Noise due to wrong or incorrect commissioning

In many cases, the noise problems are caused by the system operating at too high a speed, resulting in a higher flow than is needed. When this happens, it forces the valves to compensate by trying to close, causing friction in the system which can create noise. 

Another cause is lack of balancing or wrong commissioning of the entire heating system, which causes uneven flow and pressure across the system. This causes high stress in some parts of the system and results in noise from radiator valves. 

Noise due to wrong dimensioning

A common reason for noise in the heating systems is incorrect dimensioning of the system parts. If the pipes are not sufficiently dimensioned according to the needed flow it can create friction noise in the pipes and valves.  

Other common reasons to FIND noise in the system

Air in the system, resonance noises, cavitation noise and deposit build-up are other causes that can create noise in the system. 

How to avoid it

Correct selection, sizing and commissioning of the pump, including correct selection of pump settings with automatic adaptation (i.e. AUTOADAPT), will ensure that the differential pressure will not exceed the normally needed level. A balanced system will remove any uneven flow and pressure across the heating system, minimising the risk of noise when heat demand changes during the year.  

Grundfos Lab Tested

Grundfos circulators are tested in Grundfos’ own sound laboratory. In the sound lab the circulators undergo very comprehensive noise tests with focus on the noise emitted through air, water and the piping structure. We strive to make our pumps as quiet as possible, but, no matter how well-tested these components are, it is impossible to fully replicate the diversity of real installations. This means you as an installer play a crucial role in designing, dimensioning and commissioning heating systems correctly. 

When the system is noiseless, it often means it’s running optimally and the homeowner is ensured full comfort and optimal energy consumption throughout the entire heating system.

To find out more about the Grundfos circulator range and how they can be used to balance a heating system quickly and accurately, head to www.grundfos.ie or speak to sales at +353 (0)1 408 9800.