Check water level of heating

Check the waterlevel of your heater a couple of times a year.

The past time we've had a lot of cold days and the waterlevel might be low or too low.

To check, turn the heater to 12 degrees celcious.
Wait until the panels don't feel hot anymore.
Check the meter.

If necessary add water. but not precisely to the 100% level, but to about 85 to 90%.
When the water gets warm it needs more space.

Close the heater and turn it to about 18 to 22 degrees and wait.

Release air if needed. When the heating ticks there's still air in the system.