Today I decided to start planning for the install of some home automation kit, specifically related to heating, but while planning on that I decided to take a closer look at a problem I’ve been having for some time – the thermostat hasn’t been doing very much.<\/p>\n\n\n\n
This is a standard dial thermostat – and as you would expect, the numbers on the dial are a little off (~6\u00b0C) compared to the actual temperature. This isn’t the actual issue, since once you find the comfortable point, it doesn’t really matter what the reading on the dial is.<\/p>\n\n\n\n
The issue I was having was that, regardless of the thermostat position, the radiators were always on (except in the rooms with thermostatic valves) – I had managed before the summer by running with the timer on the boiler, and reducing the boiler temperature.<\/p>\n\n\n\n
This has the side effect of (1) the boiler operating less efficiently, and (2) I can’t use it for heating the hot water as the temperature isn’t high enough.<\/p>\n\n\n\n
After some digging, I got to this simple diagram of the basic setup:<\/p>\n\n\n\n As you can see, the thermostat doesn’t directly influence the boiler at all – instead it controls the actuator, which in turn allows hot water to flow, or not, through the radiator loop.<\/p>\n\n\n\n Taking a multimeter to the two wires in the Thermostat, I could see that it was in fact switching – 240V between the two when turned off vs 0V between the two terminals when it was on.<\/p>\n\n\n\n![\"\"](\"https:\/\/www.flat-planet.net\/wp-content\/uploads\/2019\/01\/HeatingLoop.png\")
<\/figure>\n\n\n\n