Hi guys,
First off sorry for the long post!
So a couple of a weeks ago I bought two of the new 3rd gen (with hot water control) Nest thermostats, and yesterday was meant to be the day of installation (I paid for professional installation direct from Nest).
The guy (from a company called HCM which are meant to be a ‘Nest Certified’ installer) turned up 2 hours late with no apology, then went on to (via getting mud all over my new carpet as he didn't take his shoes off) have a look at my heating/hot water system for about 20min, and decided he didn't have a clue what he was doing and due to the fact that he had never fitted a thermostat to a 2 zone system, or fitted the new Nest with hot water control said he could not do it. He then just went on to criticise the Nest thermostat, multi zone heating, and everything else under the sun. He left and that was that. How he can call himself a professional is beyond me, he was a total embarrassment to the profession and had no clue what he was doing.
I have a complaint in with Nest at the moment, and they are trying to book me a new installer but I have totally lost faith in them. As such I want to install it myself, as I'm pretty handy when it comes to DIY, and have done plenty of domestic electrical work before (extending ring mains, adding outside lights on RCD protection circuits, moving/adding lights in rooms etc), and I have a fluke multimeter and know how to use it properly. However I've never worked on a heating system before, so that’s where I’m hoping you guys can help!
My house is a new build (around 14 months old) with a S-plan based Baxi ‘System’ boiler, and a unvented Megaflow hot water cylinder that has 2 heating zones (one upstairs, and one downstairs), with a thermostat/programmer for each zone. The downstairs (zone 1) thermostat/programmer also controls the hot water timings, while the upstairs one just controls the temp and timings for the upstairs zone (zone 2). At the moment each zone (and hot water) can come on separately according to the schedule on that particular thermostat/programmer (i.e. we don’t heat downstairs when we are in bed upstairs). It all works great, see pics below.
So, how do I go about replacing my current thermostat/programmers with the new Nest ones? I understand the 3 zone valves (zone 1, zone 2, and hot water) need wiring up to the heat link box (AFAIK once wired up to the zone valves and triggered (i.e. calling for heat), the micro switch in the zone value then will send power to the boiler to fire up), and then I need to use the current wiring to the old thermostat/programmers (I’m putting the new Nest thermostats in the same place as the old thermostat/programmers) to carry the 12v power from the Heat Link box to the Nest thermostat (I know that can’t be powered by 240v). So in a nut shell, I need to find out which wires for each thermostat/programmer to use for 12v, and to understand which wires I need to wire from the zone values into the nest heat link box. I was thinking in the meantime, just get the zone valve wiring sorted and power the Nest from USB and get that all working, and then look at the 12v power to them.
Some specific questions to start off:
I seem to have two wiring centres, one on the front of the Megaflow cylinder, and one on the wall inside the airing cupboard where the cylinder is. Where should I be making the connections to the Nest heat link box, or does t not matter?
What type of conductor should I be using to make to connections to the heat link box? 1.5mm heat resistance flex?
The 3rd gen Nest install guide is here, which has wiring diagrams: https://s3.amazonaws.com/support-as...Nest-Learning-Thermostat-Install-Guide-UK.pdf
Thanks so much guys, I’m determine to get this up and running myself, while learning and improving my knowledge of heating systems
Cheers
Matt
First off sorry for the long post!
So a couple of a weeks ago I bought two of the new 3rd gen (with hot water control) Nest thermostats, and yesterday was meant to be the day of installation (I paid for professional installation direct from Nest).
The guy (from a company called HCM which are meant to be a ‘Nest Certified’ installer) turned up 2 hours late with no apology, then went on to (via getting mud all over my new carpet as he didn't take his shoes off) have a look at my heating/hot water system for about 20min, and decided he didn't have a clue what he was doing and due to the fact that he had never fitted a thermostat to a 2 zone system, or fitted the new Nest with hot water control said he could not do it. He then just went on to criticise the Nest thermostat, multi zone heating, and everything else under the sun. He left and that was that. How he can call himself a professional is beyond me, he was a total embarrassment to the profession and had no clue what he was doing.
I have a complaint in with Nest at the moment, and they are trying to book me a new installer but I have totally lost faith in them. As such I want to install it myself, as I'm pretty handy when it comes to DIY, and have done plenty of domestic electrical work before (extending ring mains, adding outside lights on RCD protection circuits, moving/adding lights in rooms etc), and I have a fluke multimeter and know how to use it properly. However I've never worked on a heating system before, so that’s where I’m hoping you guys can help!
My house is a new build (around 14 months old) with a S-plan based Baxi ‘System’ boiler, and a unvented Megaflow hot water cylinder that has 2 heating zones (one upstairs, and one downstairs), with a thermostat/programmer for each zone. The downstairs (zone 1) thermostat/programmer also controls the hot water timings, while the upstairs one just controls the temp and timings for the upstairs zone (zone 2). At the moment each zone (and hot water) can come on separately according to the schedule on that particular thermostat/programmer (i.e. we don’t heat downstairs when we are in bed upstairs). It all works great, see pics below.
So, how do I go about replacing my current thermostat/programmers with the new Nest ones? I understand the 3 zone valves (zone 1, zone 2, and hot water) need wiring up to the heat link box (AFAIK once wired up to the zone valves and triggered (i.e. calling for heat), the micro switch in the zone value then will send power to the boiler to fire up), and then I need to use the current wiring to the old thermostat/programmers (I’m putting the new Nest thermostats in the same place as the old thermostat/programmers) to carry the 12v power from the Heat Link box to the Nest thermostat (I know that can’t be powered by 240v). So in a nut shell, I need to find out which wires for each thermostat/programmer to use for 12v, and to understand which wires I need to wire from the zone values into the nest heat link box. I was thinking in the meantime, just get the zone valve wiring sorted and power the Nest from USB and get that all working, and then look at the 12v power to them.
Some specific questions to start off:
I seem to have two wiring centres, one on the front of the Megaflow cylinder, and one on the wall inside the airing cupboard where the cylinder is. Where should I be making the connections to the Nest heat link box, or does t not matter?
What type of conductor should I be using to make to connections to the heat link box? 1.5mm heat resistance flex?
The 3rd gen Nest install guide is here, which has wiring diagrams: https://s3.amazonaws.com/support-as...Nest-Learning-Thermostat-Install-Guide-UK.pdf
Thanks so much guys, I’m determine to get this up and running myself, while learning and improving my knowledge of heating systems
Cheers
Matt
