Help Understanding Nest UK install in S Plan System

[RyanM29]

Hi Guys

I'm not seeking to install this, just get an understanding of why i'm being told what I am. I'm going to pay a professional to install it but still want to understand how it works...

I recently thought it'd be a good idea to get a Nest Thermostat 3rd gen, our thermostat in our house is woefully situated and we figured we'd save a small fortune on having it learn when we are out of the house.. after a bit of research we figured it'd work with our boiler and bought it.

I was quoted £20 by our regular gas tech to fit it on top of the normal price for a service.. bargain... I thought. We'd understood that it should be a simple switch to replace the existing programmer for the nest.

But he arrived and had a bit of an issue with the whole thing, mentioned the motorized valves, thermostats, decided I needed to buy two heat links and pretty much left the building.

Our Setup:
Icos HE24 boiler
Room Thermostat
Programmer that does heating + water...
Motorized valve ground floor for entire radiator system
Motorized vavle beside hot water tank for hot water
S-Plan Wiring System

My admittedly laymans understand of the whole thing was that the Heatlink would just be a fancier version of my existing programmer. Ideally we would just leave the room thermostat in place but either a) disconnected or b) turned up to max to make it not an issue. The thought then was that the Heatlink would control both the hot water and radiators from the thermostat in our living room.

I'm told that I will need to either have two heat links or run a wire between both motorized valves to my heat link.

Having then decided to phone a nest pro he's suggested a wire between the systems may be required. Admittedly he has not seen my system.

But the house is less than 10 years old, built by a reasonably reputable builder so i'd doubt the install is too whacky.

Is anyone able to explain why this is the case? I would have thought the heat link would command both motorized valves just as the programmer does currently.

Bit Baffled by it all. Any light that can be shed on this would be gratefully appreciated.

 

[Aquaheat]

No need for two heatlinks. Just need the wiring centre and it can be done from there. I'm not surprised he couldn't do it £20 hardly inspires confidence as that is too cheap. Also doubtful if you will need to link across the system as it is all from the wiring centre. Get a decent engineer in and it should be done in an hour. The wiring diagram is on page 24 of the manual if you are competent with wiring it's easy enough to follow if you are competent with electrics. If not get a guy in as it is all to easy to fry your nice new stat.

Jon

 

[Dan Robinson]

Motorized valve ground floor for entire radiator system

Is this not with the other zone valve?

 

[Dan Robinson]

suggested a wire between the systems may be required

Sounds about right. Your £20 man doesn't seem to have a clue.

 

[RyanM29]

Thanks for the replies guys.

I've had a bunch of work done by the original company and generally they're really good, I think this was outside his comfort zone. I'm reasonably confident with electrics, but maybe not £200 of confident. Sounds like we'll be fine.