Two questions - one MG related

PQD44 wrote: David for 2, Live in goes to 3 COM, when the temperature drops the thermostat will switch and allow the 'switched live' to go out from 1. You will not normally use 2 unless you want a switched live when the temperature is above the one you set, if for instance you want to switch a cooling appliance on.

The connection of Neutral is made at the appliance/boiler.

Phone me if you need any more help

Correct, live from boiler to 3 (com) Live back to boiler from 1, to energise boiler, No neutral and no Earth. Presume batteries are to activate switch? - Only ever used Honeywell which need a neutral to activate the switch.

David Aiketgate wrote: ...Now if i put an ohmeter across 3 and 2 and rotate the dial I get an on /off when the thermostat clicks.
If I put the ohmeter across 3 and 1 and rotate, I get nothing.

You've blown the contacts :nonod: by the sound of it. Time to take it back, tell them you checked it and it doesn't work, whilst trying not to look guilty :oops: or own up and buy a new one like a responsible numpty who has learnt that you ask before connecting the wires. :silly:

At least you're here to tell the tale :thumbsup:

cjj wrote: Have a look at page 15 on here: http://www.thermsaver.co.uk/media/pdf/controls/thermsave-celect-programmable-thermostat-guide.pdf

NO means Normally Open and is Number 1 on your diagram.

NC means Normally Closed and is number 2 in your diagram. Nothing is connected to this one.

Ta!
So.......................if I want the unit to switch on a pump if a temp reaches a minimum level... 3 and 2...? err 3 and 1? err...

When the temperature drops to your preset level, the contact will change over to the NO contact (1). which feeds your central heating. When it reaches the temperature you want, the contact de energises and moves back to thye NC contact that has nothing connected to it. You could, in theory, connect anything you want to contact 2, as long as it is withing the rating of the switch.