Connecting Drayton 3 thermostat

[macadonald]

Hi guys,

I may not have enough information to get an answer, but worth a try. My builders extended the cable for our downstairs thermostat. The comHi boiler is in the loft. They removed the Drayton 3 thermostat and I assumed it had packed up as it wasn't working when reconnected, so bought an identical replacement. My electrician today could not get either working.

What confuses me is that by connecting the live and neutral together directly, the combi kicks in and we have permanent heating. When connecting the live and neutral into the thermostat, it indicates the boiler should come on witht the little flame on the display, but the boiler doesn't come on. Like the switch isnt kicking in.

There are 3 wires, but only the live and neutral are being used as indicated in the instructions. The third yellow wire is cut short.

Any suggestions? The fact that connecting the live and neutral together starts the boiler, surely means I have what I need.

Thanks mac

 

[EFLImpudence]

The fact that connecting the live and neutral together starts the boiler, surely means I have what I need.

No, it surely means that they are not live and neutral but live and switched live because connecting a live and neutral together makes a BANG.

Why could your 'electrician' not do it?
Did he say anything or just give up and go home?

There is a Drayton digistat +3. Is that yours?

 

[macadonald]

Dope, I should have thought about that. Assuming it is live and switched live, is this all I should need for the Drayton +3 to work? Yes it is the +3. The electrician was not tasked to do this, but had a stab.

 

[Spark123]

According to this clicky the drayton +3 may need a neutral to work, does yours have the L&N terminals on it?

 

[matt1e]

The fact that connecting the live and neutral together starts the boiler, surely means I have what I need.

No, it surely means that they are not live and neutral but live and switched live because connecting a live and neutral together makes a BANG.

or they maybe neither but are a elv control pair which is more common in combis, which will affect your wiring options
what is the make/model of the boiler?

Matt

 

[macadonald]

Hi Guys,

All workign now thanks to your responses and other posts from people havign similar problems. The electrician was using the wrong two terminals. It turns out that Live goes in Common and Switched live into On.

Cheers

 

[Jackrae]

But according to the installation diagrams it still needs a neutral

 

[AndyPRK]

The OP states "little flame" symbol, so its probably a drayton digistat 3 which doesn't require a netural.

 

[EFLImpudence]

Is that the same as '+3' which has a L & N on all the diagrams but states this pearl of wisdom in the text?

Digistat+3programmable room thermostats are double
insulated therefore Neutral and Earth connections are not
required. Unused existing cables should be safely insulated.

 

[AndyPRK]

No, looks like the + models are the later style, which appear to be available in mains and battery models, the former requiring a netural.