Central Heating Repairs: Checking the Thermostats


One of the first things to check on a room thermostat is that nothing in the immediate environment is triggering the heat sensor. Strong sunlight or a nearby fan heater will trip it prematurely, turning the radiators off, while draughts through a nearby door or window will cause the radiators to stay on long after they should have shut off.

Next, check the connections.

♦ Turn off the power supply to the programmer.

♦ Loosen the screw(s) holding the thermostat faceplate and lift it off.

♦ Check that the wires (there will be two or three) are held securely in their terminals.

If, after ‘click’ testing, the thermostat proves to be faulty, remove the wires one by one and note which terminals they run to. Then take the thermostat to a plumber’s merchant and obtain a matching (or near-matching) replacement.

room thermostat



Cylinder thermostats strap on to the side of the hot water cylinder. Before you do any tests, check that the strap is tight and that the back of the thermostat is in contact with the cylinder wall.

If the thermostat proves to be faulty, turn off the supply. Disconnect the wires one by one, noting their terminals, then unstrap the’ thermostat and take it to a plumber’s merchant to obtain a matching replacement.

checking the cylinder thermostat

26. May 2011 by admin
Categories: Heating, Plumbing | Tags: , , | Comments Off on Central Heating Repairs: Checking the Thermostats


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