Just for my info; did you leave the thermostat wiring in place, or remove it from the wiring centre? It might help me assist others in the future.
Nest Installation Issues
- Thread starter MrMoo123
- Start date
Sponsored Links
I left the wiring in place - I just connected together and ran the live into the call for heat on the heat link. I left the wiring centre under the pump alone. I guess it gets all the power it needs when the heat link calls for heat.
My only issue now is the Nest Thermostat not being on the wall in place of the old one. Very close to the location I have a light switch. I know not ideal but, technically, could I spur off that to give the thermostat power? Will it be too high voltage? Not sure if I would need to wire in a transformer to drop the voltage to 12v or not?
My only issue now is the Nest Thermostat not being on the wall in place of the old one. Very close to the location I have a light switch. I know not ideal but, technically, could I spur off that to give the thermostat power? Will it be too high voltage? Not sure if I would need to wire in a transformer to drop the voltage to 12v or not?
The Nest thermostat needs a 12V supply. It can be wired into terminals T1 & T2 at the Heatlink which provide a 12V supply specifically for that purpose, or it can be powered via a local 'plug in' power supply. The Nest thermostat must not be directly connected to the mains.
Sometimes, the old disconnected cable going to the original thermostat wires can be used to get the 12v from the Heatlink to the Thermostat. But not in your case as they are still live.
Sometimes, the old disconnected cable going to the original thermostat wires can be used to get the 12v from the Heatlink to the Thermostat. But not in your case as they are still live.
Yes I understand that - but to keep the thermostat where it was I can't run wires all the way back to the heatlink without ripping up floorboards and plasterboard. So, I need 12v - therefore could I, technically, spur off the nearby light switch and connect a 240v - 12v transformer between that spur and the Nest Thermostat? Hope that makes sense.
Sponsored Links
In theory it's OK, but it's not really good practice to connect a 13A socket outlet to the lighting circuit in order to plug the Nest power supply in. Someone who wasn't aware of that could come along, and plug something else in, such as a vacuum cleaner and it would overload the lighting circuit and trip the MCB or blow a fuse.
It is also unlikely that the light switch will contain a neutral, it normally only has a live supply and switched live(s) going to the lights. The neutrals normally go directly from light fitting to light fitting and don't drop down to the switches.
Having said that, it is not uncommon for a socket in a loft to be wired to the upstairs lighting circuit to provide power for a TV amp / distribution system for example, but I guess the reasoning there is that it is less likely for the socket to be used for anything else.
It is also unlikely that the light switch will contain a neutral, it normally only has a live supply and switched live(s) going to the lights. The neutrals normally go directly from light fitting to light fitting and don't drop down to the switches.
Having said that, it is not uncommon for a socket in a loft to be wired to the upstairs lighting circuit to provide power for a TV amp / distribution system for example, but I guess the reasoning there is that it is less likely for the socket to be used for anything else.
I know, totally agree it's not ideal it's just going to save me such a headache running cables from elsewhere. When I next decorate I will 'do it properly' but should get it working as I want for now. I won't have a plug there or anything, it will literally go from switch to transformer (burried behind the old thermostat box so I can still get to it if there's a problem) and from there straight into the nest so I can't see anyone accidentally plugging into it, it would only be if they ever wanted to change thermostat but would probably then be grateful for the 12v.
Will check if I have a neutral or not - might be a non starter!
Will check if I have a neutral or not - might be a non starter!
If you do have a neutral and are planning to use a non Nest supplied power supply be careful that it is to the same specification, I imagine that the nest power supply is smoothed and rectified, not just 12vac straight from a transformer. Electronics can be easily damaged by a poor power supply.
Also if you are not using a plug, don't forget you will still need to incorporate a 3A fuse somewhere.
I would also be concerned about burying it, from the fact that if it's hidden someone could knock a nail into it in the future and also because it would inhibit ventilation and it may overheat.
Also if you are not using a plug, don't forget you will still need to incorporate a 3A fuse somewhere.
I would also be concerned about burying it, from the fact that if it's hidden someone could knock a nail into it in the future and also because it would inhibit ventilation and it may overheat.
As it turned out, I don't have a Neutral so have decided to wire it in via a fused spur from a socket further along the wall.
Good call, it's a better solution.
Sorry to fire this back up again, but I have a further problem - the hot water, while hot, isn't as hot as it used to be. Before I couldn't hold my hand under the hot water tap without scalding myself... now I can leave my hand there forever no problem.
Also when I tell the nest to boost the hot water, the boiler isn't firing up which I presume it should do?
I have checked the wiring and everything is connected... the wire that calls for hot water is in 6 and there is a live going into 5 on the heat link.
I'm thinking that the old thermostat wiring that runs to the pump could be the issue ? I wired that into the call for central heating, so that's only going to fire up when the central heating is on. Do I need to have this also connected to the call for hot water or does that not make any sense?
Also when I tell the nest to boost the hot water, the boiler isn't firing up which I presume it should do?
I have checked the wiring and everything is connected... the wire that calls for hot water is in 6 and there is a live going into 5 on the heat link.
I'm thinking that the old thermostat wiring that runs to the pump could be the issue ? I wired that into the call for central heating, so that's only going to fire up when the central heating is on. Do I need to have this also connected to the call for hot water or does that not make any sense?
MrMoo123, Sorry, but I don't really understand any of your last post, other that the hot water is not hot enough. The temperature of the hot water should still be controlled by the cylinder thermostat.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
