Honeywell T40 Room stat

[trotter]

Just bought a house and was looking forward to setting my temperature via the stat (didn't have one previously) at a nice sensible heat.

However I'm finding the heating is either 'off' or 'too hot'.

The Honeywell T40 dial room stat, if I try to set it below 20, clicks ... and the heating goes off.

Sometimes this click kicks in at about 18... I can't work it out.

Is there some way to set the temperature at which it clicks on / off?

 

[picasso]

Check to see if the stat has a neutral connected, these stats tend to swing about 8 degrees without it connected.

 

[D_Hailsham]

A neutral connection will reduce the differential to about 2C. If you want anything better, you will have to install a digital thermostat, e.g Honeywell DT90E.