sub-assembly through which the heat-conveying liquid flows, at either the flow or return of a heat-exchange circuit, and which emits a signal, which is a function of the volume or the mass or the volumetric or mass flow rate, tajur, mille kaudu soojust hoidev vedelik voolab kas soojusvahetusahela voos või tagastuse juures ja mis edastab signaali, mis on seoses mahu või massiga või mahu- või massivookogusega, device containing at least the following elements: an electrically insulating meter tube through which the conductive fluid to be measuredflows; one pair of electrodes across wich the signal generated in the fluid is measured; an electromagnet for producing a magnetic field in the meter tube, type of flow instrument that is used to indicate the amount of liquid, gas, or vapor moving through a pipe or conduit by measuring linear, non-linear, mass, or volumetric flow rates