Nest 3G install help please, replacing Honeywell

[SeanRhodes]

Hi

I ordered a Nest 3G and want to install it replacing a Honeywell system.

Everything I know is:
Potteron Boiler
Megaflow Tank
Honeywell ST9100C1006
2 x Honeywell Thermostats

The 2 Honeywell thermostats do upstairs and downstairs but I would like the nest to just do the whole house.

Pictures for the wiring is attached, not the clearest so main unit has wires N, L, 1 and 4 and thermostat just has A and B.

If anyone can point me in the right direction it would be very much appreciated.

Thanks

Sean

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[Octopus]

Hum... maybe employ a spark who installs Nest systems?

 

[SeanRhodes]

That would be the easy and logical option but...

Have a 10 year warranty with the people who put in the heating system, which is void by another company touching anything (if they found out I guess). I did speak to one of their guys who was here the other day (fixing a towel rail issue) and he said just put it in myself and then remove if I needed a warranty claim. He said it should just be old wire 1 into Nest 2 and old wire 4 into Nest 5 but the heating stayed on constantly.

 

[davesparks]

That would be the easy and logical option but...

Have a 10 year warranty with the people who put in the heating system, which is void by another company touching anything (if they found out I guess). I did speak to one of their guys who was here the other day (fixing a towel rail issue) and he said just put it in myself and then remove if I needed a warranty claim. He said it should just be old wire 1 into Nest 2 and old wire 4 into Nest 5 but the heating stayed on constantly.

Then you have been advised very badly, they can't void the boiler warranty for having a qualified professional fit new controls.

You need to alter the existing heating wiring to remove the existing thermostats safely and alter from two zones down to one. Also you need to ensure that you do not disturb the safety device connected in the hot water part of the circuit, otherwise this could have dire consequences in a fault.
Your existing programmer appears to have 1,2,3and 4 connected, which is unusual and suggests that you may have non-standard motorised valves, the best will work with this but you need to know what you are doing.

 

[davesparks]

He said it should just be old wire 1 into Nest 2 and old wire 4 into Nest 5 but the heating stayed on constantly.

That is nonsense, 2 on a nest is heating common and 5 is hot water common, the two terminals are not connected in any way but would normally both be linked to perm live to give you hot water and heating on and off signals on 1,3,4,5

 

[SeanRhodes]

2 and 3 aren't connected, its just 1 and 4 (5 wires in total = Ground, Live, Neutral, 1 and 4).

Would it be feasible for me to do, maybe just with by getting another nest to keep the upstairs + downstairs?

Or maybe fight the guys who put the boiler in?

Thanks!

 

[davesparks]

2 and 3 aren't connected, its just 1 and 4 (5 wires in total = Ground, Live, Neutral, 1 and 4).

Would it be feasible for me to do, maybe just with by getting another nest to keep the upstairs + downstairs?

Or maybe fight the guys who put the boiler in?

Thanks!

Ok, then your existing programmer doesn't follow the usual wiring scheme, you'll need to read the wiring diagram to work out what does what.

It's feasible for anyone who understands how a simple boiler control circuit works, and how to carry out electrical work safely and test it properly.

Whether you have one or two nests you will still need to safely identify and disconnect the existing thermostats from the wiring centre and join the best straight through the the heating valve(s)
And if you are fitting the best in place of the existing thermostat then you will need to reuse the existing cables and connect them to the nest.
Normally the easiest place to fit the nest heatlink is next to the wiring centre (usually in the airing cupboard with the valves etc)

 

[davesparks]

I don't want to look like I'm trying to profit from this, but your location is very near me so PM me if you would like a quote.

 

[SeanRhodes]

I think I just sent you one!

Not the normal forum PM option that I could see...

 

[davesparks]

I think I just sent you one!

Not the normal forum PM option that I could see...

Yeah you did, I have replied