A heating circuit refers to the piping system that carries hot water from the boiler to radiators or underfloor heating and back. This is also commonly called a heating zone.
Depending on the heating system, there are many ways to find out if you have more than one heating circuit. Here’s what you should look out for:
Do you have a mixer module in your heating system?
A mixer module regulates the temperature of the water supplied to different heating circuits from the boiler. It is usually found in the boiler room and is a box with many pipes connected to it. If you have a mixer module in your system, you most likely also have an underfloor heating circuit.
Do separate thermostats control the heating of each floor of your home?
Sometimes, the heating on each floor of a house is controlled by a separate heating circuit. So, for instance, if you have two floors with one thermostat per floor, it is likely that these two thermostats control two separate circuits.
Does the central controller on your boiler show information about heating circuits?
Some central controllers can control multiple heating circuits at once. Check the display or installer menu of your controller. If it shows information about heating circuits (for example, heating circuit 1 and 2, HC 1 and 2, or boiler circuit and mixer circuit), this could mean that multiple circuits are active in your heating system.