Central heating consumption meter circuit - has temp. sensor leads conducting signal in opposite direction to initiate electrically-operated valve assigned to radiator

摘要

An electrical circuit for a heat consumption meter counteracts deliberate or accidental interference with the leads. At least one temp. sensor is installed in the region of each radiator used in the central heating system. The measured values are conducted to the meter via measuring leads. The radiator has an electrically-operated valve for turning-on the heating flow. The valve is controlled by a signal conducted via the temp.-sensor measuring leads. The latter can form part of a circuit carrying currents flowing in various directions. The polarity arising on the measuring leads for transmitting the sensor's measured values can be temporarily switched round to transmit the control signal. The resistance of the current carrying circuit can be substantially smaller in the control signal transmitting direction than in the other direction.