Chaining two thermostat bridges

[oldbutnotdead]

Fair choice (bathroom and loos always warm). If you do go choice 2, you could end up with a nest v Tado sketch (where the Nest stat says its cold so fires the boiler, Tado valves are all up to temperature (or off) so unless the Nest stat is in the bathroom/loo the boiler will run continually through any Nest timed periods

 

[sndp]

Fair choice (bathroom and loos always warm). If you do go choice 2, you could end up with a nest v Tado sketch (where the Nest stat says its cold so fires the boiler, Tado valves are all up to temperature (or off) so unless the Nest stat is in the bathroom/loo the boiler will run continually through any Nest timed periods

I get what you mean, I'm aiming for a Nest as the master sort of control

Bring Nest up to 23c, all the TRVs will change their setpoints to 23c
I can change the TRV temps individually until the next Nest temp change or when home/away is triggered

 

[oldbutnotdead]

Mmm. Is home/away on the Nest and does it push a very low setpoint at the TRVs?

 

[sndp]

Mmm. Is home/away on the Nest and does it push a very low setpoint at the TRVs?

Home/Away is controlled by Tado, so if the Tado system detects that no one is within the geofence then the Nest switches to Away mode too. So there's no issue with the boiler/rads heating up while I'm away.

 

[graphium]

Hi All,

I am in a very similar situation as the thread starter. However, in my case I would like to have both controllers wired in parallel, so either of thermostats can call for heat and start the boiler, so effectively the boiler will supply heat unit both controllers are satisfied.

I have a Y plan system (1 heating zone), which currently is controlled by Nest 3rd gen. I have a quite old boiler, which is just controlled by 230V on/off. In my nest’s heatlink I have 230V wired to common (nest terminal 2) and then call for heat (nest terminal 3) is wired to my heating zone valve, which then when opens, powers the pump & boiler. I am going to add number of tado smart TRV’s and tado thermostat to my son’s bedroom, so it can also call for heat independently.

So in this scenario I would just add Tado controller in parallel to nest so both commons would be linked together and both “call for heat” would go to the same zone valve.

My question is: is there any risk of any damage of controllers/relays when only one of the controllers calls for heat when the other does not – so in this case let’s say that only nest calls for heat and sends 230V to the zone valve, and then the same 230V is fed back to tado “call for heat” (as they are now linked) - even though tado does not call for heat, it gets 230V fed back to call for heat terminal, any possible issues with this ?

 

[bernardgreen]

so if the Tado system detects that no one is within the geofence

How does the Tado systm detect that no one is within the geofence, ?

Does it rely on people living in the house carrying GPS activated mobile phones with them when in the house. ?

 

[graphium]

Hi All,

I am in a very similar situation as the thread starter. However, in my case I would like to have both controllers wired in parallel, so either of thermostats can call for heat and start the boiler, so effectively the boiler will supply heat unit both controllers are satisfied.

I have a Y plan system (1 heating zone), which currently is controlled by Nest 3rd gen. I have a quite old boiler, which is just controlled by 230V on/off. In my nest’s heatlink I have 230V wired to common (nest terminal 2) and then call for heat (nest terminal 3) is wired to my heating zone valve, which then when opens, powers the pump & boiler. I am going to add number of tado smart TRV’s and tado thermostat to my son’s bedroom, so it can also call for heat independently.

So in this scenario I would just add Tado controller in parallel to nest so both commons would be linked together and both “call for heat” would go to the same zone valve.

My question is: is there any risk of any damage of controllers/relays when only one of the controllers calls for heat when the other does not – so in this case let’s say that only nest calls for heat and sends 230V to the zone valve, and then the same 230V is fed back to tado “call for heat” (as they are now linked) - even though tado does not call for heat, it gets 230V fed back to call for heat terminal, any possible issues with this ?

I think I am going to give it a go over the weekend. I asked an electrician at work, And he thinks that shouldn't be a problem....

 

[Wa77i0r]

I think I am going to give it a go over the weekend. I asked an electrician at work, And he thinks that shouldn't be a problem....

Did this work for you ? I'm as looking to connect the Nest heat link and Tado receiver in parallel

 

[ericmark]

Did this work for you ? I'm as looking to connect the Nest heat link and Tado receiver in parallel

One really should start your own thread, but I have Nest Gen 3 and Wiser, and although I have a Wiser room thermostat, in theroy no need for one, the Wiser hub will work with Wiser TRV heads alone. I did not realise this when I got it.

So now I can add Wiser TRV to any room I want to start the boiler running, at the moment a mixture of eQ3, Kasa, and Energenie TRV heads. And the living room has two TRV's so the Wiser desk top thermostat suits, at moment on a stand, once I have decided on best location, it will likely be fixed to the wall.

Plus and minus points, the Nest Gen 3 lights up as you approach it, showing both target and current, work with both phone and PC, has no batteries needing changing, boots up quickly after isolating boiler, however will not link in a meaningful way to TRV heads, and the need for power from same FCU as boiler means to relocate rather a problem.

The wiser only shows a display when it is touched, it will not work with PC only works with phone or tablet, it takes around 10 minutes to boot up after the hub is turned off, relies on batteries in the thermostat, can't be configured for thermo syphon DHW so I only use the single channel model, but it does work with TRV heads and the thermostat is portable so can be placed in any room, basic idea the wiser turns the heating on, and the TRV's turn the heating off.

However both give info on how the heating is working, neither are any good, as neither gives whole picture. I know the Nest Gen 3 can learn, not looked at wiser as yet, but I know with Nest all the bells and whistles had to be turned off, had heating fail because the EE mast was damaged in high winds, that is not what I want. It would fire up DHW to stop legionnaires, but the iboost+ was heating the DHW with solar.

Both Nest Gen 3 and Wiser will work with OpenTherm, but my boiler will not, and I don't think there is any way to get two OpenTherm thermostats to work together, only simple on/off type.

Anyway the two thermostats work OK for me, the Nest in hall is reasonable average of whole house, but hall is slow to cool, so Wiser ensures living room does not get cold, but can't using living room only as it has doors to outside and a open fire, and the Wiser does not do the DHW only the room temperature. So now I have best of both.

Had I wanted OpenTherm then it would have been very different.

 

[Mister Banks]

One really should start your own thread, but I have Nest Gen 3 and Wiser, and although I have a Wiser room thermostat, in theroy no need for one, the Wiser hub will work with Wiser TRV heads alone. I did not realise this when I got it.

So now I can add Wiser TRV to any room I want to start the boiler running, at the moment a mixture of eQ3, Kasa, and Energenie TRV heads. And the living room has two TRV's so the Wiser desk top thermostat suits, at moment on a stand, once I have decided on best location, it will likely be fixed to the wall.

Plus and minus points, the Nest Gen 3 lights up as you approach it, showing both target and current, work with both phone and PC, has no batteries needing changing, boots up quickly after isolating boiler, however will not link in a meaningful way to TRV heads, and the need for power from same FCU as boiler means to relocate rather a problem.

The wiser only shows a display when it is touched, it will not work with PC only works with phone or tablet, it takes around 10 minutes to boot up after the hub is turned off, relies on batteries in the thermostat, can't be configured for thermo syphon DHW so I only use the single channel model, but it does work with TRV heads and the thermostat is portable so can be placed in any room, basic idea the wiser turns the heating on, and the TRV's turn the heating off.

However both give info on how the heating is working, View attachment 360896 View attachment 360897 neither are any good, as neither gives whole picture. I know the Nest Gen 3 can learn, not looked at wiser as yet, but I know with Nest all the bells and whistles had to be turned off, had heating fail because the EE mast was damaged in high winds, that is not what I want. It would fire up DHW to stop legionnaires, but the iboost+ was heating the DHW with solar.

Both Nest Gen 3 and Wiser will work with OpenTherm, but my boiler will not, and I don't think there is any way to get two OpenTherm thermostats to work together, only simple on/off type.

Anyway the two thermostats work OK for me, the Nest in hall is reasonable average of whole house, but hall is slow to cool, so Wiser ensures living room does not get cold, but can't using living room only as it has doors to outside and a open fire, and the Wiser does not do the DHW only the room temperature. So now I have best of both.

Had I wanted OpenTherm then it would have been very different.

You need to have one system controlling everything, don’t mix and match between systems. It’s a strange way to work having multiple systems all trying to learn how your house heats and cools and conflicting with each other.

 

[ericmark]

You need to have one system controlling everything, don’t mix and match between systems. It’s a strange way to work having multiple systems all trying to learn how your house heats and cools and conflicting with each other.

I am sure if I was designing the house, I could fit some thing like this and all would be fully integrated. However house already built, and hard to install new wiring or plumbing, so have to work with what I already have, wires from hall to utility room I assume was thermostat to programmer, the utility room to under house in the flat starts as red, yellow, blue, arrives as brown, black, grey, and some where clearly a hidden joint, and one core open circuit.

So 1) seems prudent to use extra low voltage, 2) need to control both central heating and domestic hot water with two wires. 3) also need to power it using same two wires, so question was, what will do that, and the answer was Nest Gen 3, however it was found in spite of what they said, it did not connect in a meaning full way with the energenie TRV heads, it did connect, but not in any helpful way.

Nest thermostats can be powered with USB, but to get USB powered from same FCU as the boiler, that was not really an option. And unless powered by same FCU then any power cut, and central heating stops working.

So only other option is wireless, which means batteries, OK already 18 x AA cells to work the TRV heads, However the eQ3 designed to fail open, and one room not working is very different to whole system going down.

So having a second thermostat which needs to AA cells not so bad, as if it does fail, the other is still working. So idea is not to have all eggs in one basket, if a bit fails, the whole system does not fail, except for the boiler its self, and that is supplied from an UPS so should not fail too easily. Last back up, open the open fire and burn wood.

 

[Mister Banks]

I am sure if I was designing the house, I could fit some thing like this View attachment 360911 and all would be fully integrated. However house already built, and hard to install new wiring or plumbing, so have to work with what I already have, wires from hall to utility room I assume was thermostat to programmer, the utility room to under house in the flat starts as red, yellow, blue, arrives as brown, black, grey, and some where clearly a hidden joint, and one core open circuit.

So 1) seems prudent to use extra low voltage, 2) need to control both central heating and domestic hot water with two wires. 3) also need to power it using same two wires, so question was, what will do that, and the answer was Nest Gen 3, however it was found in spite of what they said, it did not connect in a meaning full way with the energenie TRV heads, it did connect, but not in any helpful way.

Nest thermostats can be powered with USB, but to get USB powered from same FCU as the boiler, that was not really an option. And unless powered by same FCU then any power cut, and central heating stops working.

So only other option is wireless, which means batteries, OK already 18 x AA cells to work the TRV heads, However the eQ3 designed to fail open, and one room not working is very different to whole system going down.

So having a second thermostat which needs to AA cells not so bad, as if it does fail, the other is still working. So idea is not to have all eggs in one basket, if a bit fails, the whole system does not fail, except for the boiler its self, and that is supplied from an UPS so should not fail too easily. Last back up, open the open fire and burn wood.

But why do things using different manufacturers when you could do it all with Wiser. Put Wiser TRVs on all the rads and if you allocate them on a per room basis each TRV will call for heat if required. Use Wiser room thermostats in areas where you want to group rooms together. Its so simple to just use Wiser for everything. It’s not cheap initially but what is these days.

 

[ericmark]

Historical Nest Gen 3 fitted 4 years ago. Were told it would work with the Energenie TRV heads, and using the Energenie app, one could change the temperature on the Nest and the TRV's would also change, but when the Nest did a scheduled change, they did not follow, and anyway wrong way around, want the hub to follow the TRV not TRV follow hub.

Also, Wiser does not have volt free contacts with DHW version. Nor does it have a software fix like Hive. So, putting it simply, Wiser on its own is no good for a therm-syphon system. So not possible to use all Wiser system. So, using the best of both.

 

[Mister Banks]

Historical Nest Gen 3 fitted 4 years ago. Were told it would work with the Energenie TRV heads, and using the Energenie app, one could change the temperature on the Nest and the TRV's would also change, but when the Nest did a scheduled change, they did not follow, and anyway wrong way around, want the hub to follow the TRV not TRV follow hub.

Also, Wiser does not have volt free contacts with DHW version. Nor does it have a software fix like Hive. So, putting it simply, Wiser on its own is no good for a therm-syphon system. So not possible to use all Wiser system. So, using the best of both.

Aren't you using solar for your DHW presumably with an immersion as backup? If so then Wiser can control heating in every room in your house.

 

[ericmark]

Solar will heat the top of the tank, but the immersion is too short to fill a bath using solar. In winter, can't turn DHW off (C Plan) but in summer the iboost+ gives me enough hot water for handwashing. The immersion is the solar heating.

However, this thread is not about me, I am satisfied with my heating, having multi-makes simply means the display does not really relate to what used, but with oil fired boilers that does not really matter.