The central heating control system is for use where the water or other liquid is pumped through a circuit between the boiler and one or more radiators. Pump speed is varied as a function of the difference in temperature between the actual value measured near a heat emission point and a reference value, being increased as the difference increases and vice-versa. Pump speed can be steplessly variable, and there can be a minimum speed such that circulation just continues to exist. An alternating-current motor can be used to drive the pump, speed variation being effected by a phase displacement control.
展开▼