NEST thermostats

GeForce said:
When you say "isn't working", what are they connected to?

How are you testing with the Nest if it's not connected to power? Just on battery?

Perhaps some pictures would help.
Click to expand...

Thanks, one step forward two steps back it seems.

Existing programmer and stat wiring:
http://imgur.com/epNAn3d
http://imgur.com/CzHhmSy

I've wired the heat link in place of the programmer. When I hit the button on the heat link, the boiler fires but the radiators aren't getting hot. Clearly I'm missing something but I'm not sure what. Thanks for your help.
 
One More Solo said:
Thanks, one step forward two steps back it seems.

Existing programmer and stat wiring:
http://imgur.com/epNAn3d
http://imgur.com/CzHhmSy

I've wired the heat link in place of the programmer. When I hit the button on the heat link, the boiler fires but the radiators aren't getting hot. Clearly I'm missing something but I'm not sure what. Thanks for your help.
Click to expand...

Still not quite clear on what's happening here.

Which model was your old programmer?

Can you take some pictures of how you've wired up the Heat Link?

In the first picture, can you clarify which wires go into terminals on the old programmer and which go through the hole in the wall behind the unit? It's very hard to see.
 
It's a Danfoss TP5000.

There are 6 connectors (left to right):
Neutral
Live
Common (bridged to live)
Nothing
Nothing
Call for heat

I've wired neutral and live to the same ports on the heat link. I've bridged live and common and connected the two wires connected to the call for heat on the programmer to the call for heat port on the heat link. Will get a picture.

http://imgur.com/LLbdTcb

The issue seems to be I need to connect the live wire in the thermostat to neutral to get heat to the radiators (guess it's opening a valve somewhere?), but then I only have one spare wire and an earth wire so I can't get 12v to the Nest.
 
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One More Solo said:
It's a Danfoss TP5000.

There are 6 connectors (left to right):
Neutral
Live
Common (bridged to live)
Nothing
Nothing
Call for heat

I've wired neutral and live to the same ports on the heat link. I've bridged live and common and connected the two wires connected to the call for heat on the programmer to the call for heat port on the heat link. Will get a picture.

http://imgur.com/LLbdTcb

The issue seems to be I need to connect the live wire in the thermostat to neutral to get heat to the radiators (guess it's opening a valve somewhere?), but then I only have one spare wire and an earth wire so I can't get 12v to the Nest.
Click to expand...

Yes, the wiring you've done so far is correct, the remaining thing is to bridge out the old thermostat.

Usually this is done by finding the Live (brown) and Switched Live (black) from the thermostat in the wiring centre, then removing them and jumpering those terminals.

Do you have a wiring centre? I am assuming not from the pictures.

Am I right in thinking that the brown/grey/black wires at your thermostat are the same ones that are now in T2/T1/call-for-heat at the HeatLink?

If so, I can't see why both brown and black would be connected to the call-for-heat in your old programmer.

Where did the grey wire from the thermostat go in the old setup?
 
Just lost a longer post annoyingly but in summary I think I need to use the brown and grey wires from the old programmer to get 12v to the Nest and find a way to connect the black switched live in the old thermostat to live permanently. Does that sound like the right approach?

The grey wire in the old setup was connected to neutral at the thermostat but nothing behind the programmer.

I don't seem to have a wiring centre. Would the thermostat be controlling something at the boiler end or something elsewhere? As mentioned the call for heat is firing up the boiler but there is clearly a valve somewhere stopping water getting to the rads.
 
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Ah sorry, this is the programmer: http://www.screwfix.com/p/danfoss-t...mzqZ_SolPHdCDneIAdgNUw4zbIsvn8p3bwaAiPo8P8HAQ

I have two room thermostats in the house if that helps, one upstairs and one downstairs. I'm just replacing the downstairs stat at this stage.

Everything is working as it stands having bridged the live and switched live in the thermostat at the wall, but I would much prefer to have the Nest on the wall if possible rather than using the power adapter.
 
OK, so the problem is that the grey/black/brown wires at the 'stat are NOT the same grey/black/brown wires at the programmer.

One or more of them may be the same, but certainly not all three.

The only thing to do is try and find where the live and switched live from the thermostat go to. I suspect the live comes from the CH ON on the programmer, and the switched live goes to a zone valve and the boiler.
 
I'd guess the grey and brown at the stat are the same as at the programmer but the black is the odd one out.

From what I can see the CH ON at the programmer connects to the call for heat at the boiler and to the switched live at the thermostat (which I think is what you're saying?). I've no idea where the zone valves are so may just call it quits at this point and get a blanking plate for the old stat location. The Nest can sit on the side. :p

Thanks very much for your help.
 
One More Solo said:
From what I can see the CH ON at the programmer connects to the call for heat at the boiler and to the switched live at the thermostat .
Click to expand...

I don't think this is the case, because this would power up the boiler even when the thermostat was not calling for heat.

Usually it goes CH ON at programmer -> thermostat -> boiler call for heat, and any valve positioning demands.

Do you have only one programmer but two thermostats?
 
Only one programmer but two thermostats yep.

To complicate this I've now found the wiring centre and zone valves in an upstairs cupboard. I'm going to take a break for a bit as feels like I'm back to square one but at least this means I can do a proper job of it.

http://imgur.com/Ti9xHlM
 
Lovely. I suspect the two black wires top right are the switched lives from the two thermostats. The browns connected to these go to the zone valves. This is why the rads aren't getting hot when you didn't connect L&SL at the 'stat.

You need to determine which of those black wires relates to the thermostat you're replacing with the Nest.

Then find the brown wire that is in the same cable as that black (i.e. brown that comes from the 'stat), and find which terminal it goes to. Connect valve brown for that zone to that terminal. Now you can remove the 'stat brown from that terminal.

Now your thermostat cable (black/grey/brown) is entirely unused.
 
Awesome think I'm nearly there, thanks so much for your help.

GeForce said:
Then find the brown wire that is in the same cable as that black (i.e. brown that comes from the 'stat), and find which terminal it goes to. Connect valve brown for that zone to that terminal. Now you can remove the 'stat brown from that terminal.

Now your thermostat cable (black/grey/brown) is entirely unused.
Click to expand...

So wire valve brown to permanent live if I've understood right?

My upstairs stat seems to have stopped working for some reason so I've just wired both valves to live for now, will need the radiators in the morning! Clearly gone wrong somewhere but too tired to fault find.

Thanks again.
 
One More Solo said:
So wire valve brown to permanent live if I've understood right?
Click to expand...

No, the thermostat live (brown) is not permanent live, it goes live when the programmer says "CH ON".

So you want to connect valve brown to position 3 on the HeatLink, but connect it to the relevant point in the wiring centre.

Edit: To repeat: don't connect valve browns to permanent live, this will hold both valves open all the time
 
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I picked one of these up and connected it to my boiler which has never had a thermostat connected before. Works a charm.

I was wondering how others are using the auto away / auto learning features of the thermostat. I'm just wondering if I'm using it wrong.

Presumably because the thermostat is in learning mode, it won't set auto away yet, even though I've set up the App on all phones, so geofencing should be used.

When I didn't want the heating on, like when going to bed, I changed the heating mode to 'eco'. Then when getting up I used my phone to switch the heating on. Been doing this for the past few days and was hoping it would learn that routine, but it hasn't. I'm guessing I shouldn't be using the 'eco' button, which is a nice and simple preset, but should rather be manually changing the temperature?

What are others doing?
 
The same problem im having so have downloaded skylark for a temp measure. I have asked the same question on this thread but no one has responded to me.
 
GeForce said:
No, the thermostat live (brown) is not permanent live, it goes live when the programmer says "CH ON".

So you want to connect valve brown to position 3 on the HeatLink, but connect it to the relevant point in the wiring centre.

Edit: To repeat: don't connect valve browns to permanent live, this will hold both valves open all the time
Click to expand...

Got this all sorted now and tidied up, all working as expected. :) Thanks a lot for your help and patience! Feel like I actually understand how it all works now it just took a while to get there.

The install was a lot more complicated than I expected!
 
One More Solo said:
Got this all sorted now and tidied up, all working as expected. :) Thanks a lot for your help and patience! Feel like I actually understand how it all works now it just took a while to get there.

The install was a lot more complicated than I expected!
Click to expand...

Well done! Yes the complication was mainly from the fact you have multiple zones which I did not initially realise.

Anyway, enjoy :)
 
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