Potterton Powermax 185 Nest Install

[sub2hours]

Hi all,

Apologies, another Nest example but I've not seen one for this boiler. We have a 13 year old powermax 185 (Yes, I know) that I'd like to control using Nest and Amazon Echo. I'm yet to purchase the Nest system but wanted to check my thoughts on the wiring before I go ahead.

I've attached the wiring diagram from the powermax installation guide and am planning to do the following, as per the annotations:

1. Switch off at fused spur and remove fuse.
2. Disconnect the existing thermostat wiring and use this as the 12v feed from the heat link to the Nest stat.
3. Bridge the existing stat live and return at the boiler so the Nest stat is used instead.
4. Cut the cables to the existing programmer and insert a terminal block mapping the wires to the corresponding heatlink connections.

From the diagram (powermax - Nest)

R - Live
BK - 2 and 5
BL - Neutral
O - 3 (CFH Heating)
BR - 6 (CFH Water)

T1,T2 - 12v to nest Stat



I just wanted to check the difference in wiring BK to 2 and 5 separately rather than looping R to Live, 2 and 5 (as seen in other installs). I'm thinking the former will still allow the Appliance Switch to be used to switch off the boiler, not that that is important as its been on timed for the last 13 years.

Any confirmation/pointers would be gratefully received.

thanks,

Ian

 

[sub2hours]

Picked up a Nest with a Screwfix voucher yesterday so any input on my questions above would be much appreciated.

Thanks,

Ian

 

[Manka2009]

Picked up a Nest with a Screwfix voucher yesterday so any input on my questions above would be much appreciated.

Thanks,

Ian

Hi Ian

Stumbled across your post when searching for similar experience with the powetmax 185 as i have the exact same desire as you.

I just wondered how you got on and whether you could offer any advice?
Thanks
Cass

 

[sub2hours]

Hi Cass,

Well I went ahead despite not getting any feedback from the forums and everything is working fine. I did exactly what is described in my first post, cutting the cables as they leave the powermax programmer and connecting instead to the nest heatlink.



The wiring in the spur itself was a bit tricky as it's where the thermostat, main power and boiler power cable all meet. I've included a photo of this and of a diagram I drew so that I can put it back if I ever need to do so.



The next pic is the main connections in the boiler as shown on the diagram in my first post. This is before I connected a bridging wire across 9 and 10 and removed the stat connection.



Finally a pic of the stat before I made any changes:



As I said, it's all working fine and we can now control the heating from any of the mobile phones but also by asking Alexa to "turn up/down the house temperature" or "set the house temperature to x degrees".

Happy to help if I can with any questions you may have.

Ian

 

[Manka2009]

Cracking, thanks Ian. I haven't yet purchased and after Christmas it will probably be a while yet but great to know you monitor the thread and can help if needed. Thanks for the pics too. Really helpful.

 

[Wes1326]

Hi Ian,

I was hoping you can help me with some trouble I’m having installing my nest Thermostat (to my Powermax 155x Boiler). I currently have it connected to 27 and 28 (9 and 10 on Powermax 185 model) but I soon realised that I have to have the water on 24 hours.

I then came across your post, as you have a similar set up. The current controller on my boiler fires the CH and hot water at the same time. I’m not sure if the nest would have to do the same or if it would work independently like you have done? I have attached the drawing for the Powermax 155x below.

I would be very great full for any help/advise you can offer me!

Thanks,

Wes