I've come across this floor heating mixing unit from Watts in an appartment. The image shows how things flow (I could only find this with some russian-looking annotations). To the left of the return connection there is a water meter - not an energy meter - it only shows the accumulated amount that has flown through it from the day of installation. My question is - will this meter to some extent also run when no water goes to the floor loops? I suspect it will due to water being forced through the pump by the pump in the boiler room somewhere. Any ideas?