Central Heating Digital Thermostst Help.

[DeludedDonny]

Hi all,

My new thermostat just arrived and I am seriously confused...

This is my old thermostat and its witing guide.

Yellow into 1
Red into 2
Blue into 4

this is my new thermostat.

am I right in thinking 1 & 2 is for the thermostats power supply? (there already is a power supply which has been taped off behing the old thermostat.

But I do not know where to put the red yellow and blue wires...

I read the wiki but it just confused me even more LOL...

any help would be greatly appreciated...

Thanks a million

 

[securespark]

Was it definitely yellow in 1? Yellow is usually used for a switchwire & red as the live feed, but that does not seem to be the case here. In any case, you can use a multimeter to check that.

1 is L in.

So whichever wire is the live goes to L on the new stat, the blue goes to N.

And the other wire (which goes to the pump) to NC.

What about the sensor terminals?

 

[stem]

The diagrams provide all of the information you require. In the first picture for your existing thermostat.

Terminal 1 = Live supply
Terminal 2 = Is the switched live to operate the heating
Terminal 4 = Neutral connection for the accelerator heater

NOTE: Normally Red is used for live, Yellow for the switched live, & Blue for neutral. According to your post Yellow & Red are transposed, so either the person who installed it has used different colours to the norm (which will work OK as long as they are transposed at the other end also), or you have made a mistake.

As you deduce, your new thermostat requires

Live to terminal 1 (L)
Neutral to terminal 2 (N)

Then you will need to install a wire link between terminals 1 (L) & 4 (COM) this provides a live supply to the actual switching part of the thermostat.

Finally the switched live to operate the heating should be connected to terminal 5 (NC = normally closed) so that when the thermostat operates this contact is closed and your heating operates.

You don't mention make / model of the new thermostat, so I can't check, however I'm assuming that you need to use the terminal 5 (NC) contact for the switched live. If you find it works in reverse, ie the heating comes on when the thermostat is turned down & vice versa, move the wire to terminal 3 (NO) This is because some manufacturers describe the position of the contacts with the thermostat in the on state and some with it off. If you advise us of the make and model of the new stat, we can confirm.

Pah: beaten by Securespark

 

[DeludedDonny]

Thank you both so much,

Yellow was live, I also thought it was a little strange...

So I did
Yellow - 1
Blue - 2
Red - 3
and then ran a wire between 1 and 4 it works like a charm.

Thank you both SO much.

Its just a cheap thermostat off ebay ( Its the Digital Programmable Blue Backlit one http://www.ebay.co.uk/itm/230763375...eName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 ), just a stop gap for now cos the old thermostat died and not splashing out on an expensive one cos will be redoing the CH in the near'ish future, want each of the 3 floors to be on its own thermostat. (but will get a professional in to do that)

at the moment downstairs is perfect temp, but the higher in the house you go the hotter it gets LOL

Thanks again

BTW the sensor terminals are for a floor level temp sensor, but its not needed cos it has a built in thermostat

 

[stem]

See, as easy 123.

Thanks for the link to the thermostat info. If its working correctly, then in this case the "normally open" state refers to when the thermostat is not calling for heat. But you've sussed it anyway.

 

[studentspark]

Terminal 4 looks a bit charred?

 

[ericmark]

1 becomes 1 and 4 Line Feed.
2 becomes 5 feed to boiler.
3 becomes 3 Not used.
4 becomes 2 Neutral.
and 6 and 7 go to an extra sensor.

However to have an extra sensor likely means it's for under floor heating not a general thermostat. I have seen other thermostats with a remote sensor but not on a domestic property.