Central heating timer system - enables delay of seven days to be used when heating secondary residences to preheat residence when required

摘要

This timer has a synchronous motor which drives a disc (7) with a sprital groove (10). A cam (25) is driven around this spiral so that it moves a spring-loaded radial arm (14) in a horizontal direction. The disc rotates once in 24 hours and there are seven equal spiral steps. Another disc (8) is mounted on the motor shaft and has a cam profile that rotates once in 24 hours. The cam and spiral are arranged to enable the user to preset the radial arm against graduated marks (29, 35) for any desired hour in seven days. At the end of the preset travel, a three position contactor (1) is operated by the radial arm to switch on the central heating. The timer is useful for the preheating of secondary residences.