central heating thermostat

[jolyn]

Have a mechanical room thermostat which has only 3 wires at back [ 2+ earth]. Would like to replace it as it seems to not cut off at desired temp and when manually turned down 'below click' allows the room to get very cold and will not come back on. Most digital stats seem to require 3wires +earth. Would appreciate advice.

 

[namsag]

honeywell DT200 2 wire digital stat cost about 20 quid

 

[bhm1712]

i can vouch for the dt200, its accurate and easy to install. screwfix have them instock for about 24 quid if i remember. my first room stat i bought was mechanical, it was 3 degrees wrong...and never seemed to switch

 

[D_Hailsham]

Have a mechanical room thermostat which has only 3 wires at back [ 2+ earth].

Are you sure that the "earth wire" is being used as an earth? Many mechanical stats need three wires: Live, Neutral and Switched Live. It is not unknown for the "earth" wire to be used as the Switched Live.

Modern Digital stats, e.g Honeywell DT200, only have two wires: Live and Switched Live.

 

[jolyn]

Thanks to all who replied to my query on room stat. Been a great help