System Boiler (Y-plan) with Google Nest 3rd Gen and OpenTherm?

[hometech]

You are insane mate.

Let me just copy and paste a little of the instructions for everyone to read:

Software :

Connect to each pi-heating-sensor in turn,


We can now start to install the packages and software that will read the 1-wire thermometer data and make it available the the heating controller hub.

again there is a script to do this :


once everything is installed, reboot :


now we need to edit the config file ~/pi-heating-remote/configs/sensors

but first we need the discover the serial numbers of the connected 1-wire thermometers


Will show that I have two 1-wire thermometers connected, 28-0000056e625e and 28-0000056ead51.

drwxr-xr-x 2 root root 0 Jan 25 15:23 .

drwxr-xr-x 4 root root 0 Jan 24 16:17 ..

lrwxrwxrwx 1 root root 0 Jan 24 16:43 28-0000056e625e -> ../../../devices/w1_bus_master1/28-0000056e625e

lrwxrwxrwx 1 root root 0 Jan 24 16:43 28-0000056ead51 -> ../../../devices/w1_bus_master1/28-0000056ead51

lrwxrwxrwx 1 root root 0 Jan 25 15:23 w1_bus_master1 -> ../../../devices/w1_bus_master1
Now edit the config file and insert these serial numbers.


Delete the default settings and insert the serial number and a name for each 1-wire thermometer.

remove all this :

28-000005cf873e = External

28-000005d0065c = Conservatory

28-000005d01a5a = Conservatory Rad
and add your data, e.g. :

28-0000056e625e = Lounge

28-0000056ead51 = Garden
save and close the config file.
​

Did i mention there was soldering involved?

Muppet

You not having any education whatsoever in computing (using windows is not computing) is not a reflection of the current levels of education of an average 10 yr old, it is a reflection on yourself. Most of the clubs that are running around the country are populated by youngsters, this is also taught in schools which is why I suggested using youngsters to do this job. The internet and youtube have millions of how to guides so don't heap your inability and lack of knowledge and your obvious frustration onto the cognitive abilities of others. It seems that there is now a pride taken in ones inability, a badge of honour to proclaim your unwillingness to learn and to shout with pride that you know very little...and proud of that fact.

 

[hometech]

Go and find a 10 year old! What an answer! You sound like Groucho Marx

You are disconnected from reality.

It's so easy. All you have to do is buy rasperbby pi. Learn how to turn it on, connect it to your computer and you are away! No learning the computer language you can just download the prewritten scripts made by 10-year-old (who looooooove boilers and heating. So much better than Fortnight). You won't have to learn, stress, swear and scream at this tiny little computer at all. It will all be fine and easy and plain sailing. Figuring out a multimeter will be the hardest part. It will be the only doohickey you have to buy and you can easily do it in an evening.

You have no idea what you are talking about. Please stop lying to people. The more you write, the more ludicrous you sound.

TO THE ORIGINAL POSTER - if you really want to go down this route, I have a lot of respect for your desire to understand and control your heating system. Please be aware the cost/benefit ratio will be in the negative. BUT, you will learn a lot along the way.

HOMETECH - please stop misleading people. I am sure you have a wonderful heating system but what you are so flippantly discussing is beyond the reach of nearly everyone. Including nearly every registered insured qualified experience profession heating engineer who does this for a living. I pity the person who comes to service your boiler.

wonderful system by design, not chance. I started with basics on understanding the property. I then improved where I could or it was calculated it would be beneficial. Selecting the equipment took a lot of time but knowing what I needed meant 95% progress had been made. After that It was a lot of effort in monitoring, experimentation and observation. I discovered an awful lot in the process, a knowledge I am willing to share. Maths and physics...its all you need.....

 

[hometech]

Are you high?

As high as the pressure inside your combi LOL. Give me one, just one example of a combi boiler exploding under normal usage. Just one

 

[albert85]

I decided to leave the system in the simple on/off mode for now, which is how my heating engineer has left it. He will come back to issue the gas safety certificate and has offered to make any installation tweaks I still want at the same time.

One thing I'm confused about is that he left my old Honeywell controller to work alongside the Nest Heat Link base station. I would have thought that the Honeywell controller is no longer needed if the Nest is wired in Y-plan on/off mode (page 23 of the nest installation guide.) With the cylinder thermostat directly connected to terminal 4 on the Nest.

I have attached some photos of my installation as it is wired now. Am I missing something and in fact the Honeywell controller is still required? Or can I ask my heating engineer to remove the old Honeywell controller? I'd like to leave the system in the simplest possible way, with as few components that can fail or confuse future installers.

 

[Basher]

I decided to leave the system in the simple on/off mode for now, which is how my heating engineer has left it. He will come back to issue the gas safety certificate and has offered to make any installation tweaks I still want at the same time.

One thing I'm confused about is that he left my old Honeywell controller to work alongside the Nest Heat Link base station. I would have thought that the Honeywell controller is no longer needed if the Nest is wired in Y-plan on/off mode (page 23 of the nest installation guide.) With the cylinder thermostat directly connected to terminal 4 on the Nest.

I have attached some photos of my installation as it is wired now. Am I missing something and in fact the Honeywell controller is still required? Or can I ask my heating engineer to remove the old Honeywell controller? I'd like to leave the system in the simplest possible way, with as few components that can fail or confuse future installers.

Is there an isolator (eg FCU) there for the heating controls? If not, perhaps your heating engineer left the old controller there as the simplest way of providing that 'switch'? It seems to be set to be permanently 'on'.

Or do you have another way of locally isolating the system?

 

[EvilDrPorkChop]

I decided to leave the system in the simple on/off mode for now, which is how my heating engineer has left it. He will come back to issue the gas safety certificate and has offered to make any installation tweaks I still want at the same time.

One thing I'm confused about is that he left my old Honeywell controller to work alongside the Nest Heat Link base station. I would have thought that the Honeywell controller is no longer needed if the Nest is wired in Y-plan on/off mode (page 23 of the nest installation guide.) With the cylinder thermostat directly connected to terminal 4 on the Nest.

I have attached some photos of my installation as it is wired now. Am I missing something and in fact the Honeywell controller is still required? Or can I ask my heating engineer to remove the old Honeywell controller? I'd like to leave the system in the simplest possible way, with as few components that can fail or confuse future installers.

Sorry I haven't read the thread fully. But why can't you use Opentherm without the S/L to the Ideal?

I have a system boiler using Opentherm and it works perfectly, but another brand. When you refer to Y Plan, you ideally to use Opentherm you should either use a Diverter rather than a Mid position (Referred to as W plan I believe) Or S plan using 2 two port valves.

 

[albert85]

@Basher that sounds like a likely explanation.

Judging from the attached photo I can see the cylinder thermostat wire going into the wiring centre, then to this controller, and then I think it goes directly to the boiler + Y-plan valve I (I think the Nest is bypassed because if I define a heating schedule in the Nest it doesn't appear to stop the boiler from heating the hot water cylinder.)

Do you think it would be possible to replace this Honeywell controller with a fused switch, and then go into the Nest's terminal 4, so that I can use the Nest to control the hot water schedule, in addition to the heating schedule? I like the idea of being able to turn the entire system off remotely, including the hot water.

 

[albert85]

Sorry I haven't read the thread fully. But why can't you use Opentherm without the S/L to the Ideal?

I have a system boiler using Opentherm and it works perfectly, but another brand. When you refer to Y Plan, you ideally to use Opentherm you should either use a Diverter rather than a Mid position (Referred to as W plan I believe) Or S plan using 2 two port valves.

Haha just when I had resigned myself to the idea that I won't be able to get it to work

Are you using a Nest 3rd gen thermostat? Do you mind telling me a bit more about how your thermostat controls the valves?

 

[EvilDrPorkChop]

Haha just when I had resigned myself to the idea that I won't be able to get a system boiler to work with Nest + OpenTherm

Are you using a Nest 3rd gen thermostat? Do you mind telling me a bit more about how your thermostat controls the valves?

It should work fine. Basically you need HW priority, so that it heats the HW first before any CH demand. This is so that it can demand a high flow temp to reheat the HW quick, then switch over to CH with lower flow temps.

I'm using Honeywell Evohome, but it's the same principal.

Regarding your timer, think your CH engineer has bodged it up. I think you need to start a fresh with the wiring.

In terms of my valve set up. I have 2 port valves, I have multiple zones. Basically when the HW is demanded the power to the other valves is killed so that the higher flow temperatures can't go round. So you could technically do it with the 3 port Mid position valve using some sort of relay, but really you'd do it using the W plan.

 

[EvilDrPorkChop]

Sorry, you'd have to have some way of detecting the HW temp too. I'm not sure how Nest operates with this? Evohome measures the tank temp.