help needed. replacing central heating thermostat

[mkultr4]

hi

I need to replace the thermostat on my central heating system
the original thermostat is an old drayton analogue
the new therrmostat is a tower analogue but with a different wiring scheme.

Here is the original stat with wiring diagram

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here is the new stat & diagram

i have checked the wiki on this site but i wanted to make sure i was conecting the right cable to the right terminal and was hoping for some advice.

Thanks

 

[andytw]

Connect the red from 3 and connect to 1 on the new stat.
Connect the grey from 1 and connect to 2 on the new stat.
Connect the green earth wire to the earth wire on the new stat if there is one which it doesn't look like there is, so this wire should be made safe.
The black wire connected to N on the old stat is not used on the new stat so should be made safe.

The N black is neutral and is connected on the old stat to cause a resistor to warm up when the stat is on. This warms up the metallic strip inside the stat and makes it more sensitive to a rise in temperature and so will cut out a bit earlier. It reduces the gap of a couple of degrees between the 2 clicks on the stat.
As your new stat does not have this I would just be curious as to it's model number and suitability.

andytw

 

[mkultr4]

Hi

its a tower combi-stat STTRS1

thanks

 

[75pete]

Looks a bit like my old one.