Nest thermostat

[Prezesczwa]

Hi all,
I’m not sure if this is a right channel. I have a problem with nest thermostat. I have a boiler glow worm easycom 24, with genuine wireless control panel works fine, I can change temp of heating and water, but when I install nest I can do only heating. There are only two cables to connect RF receiver to the BUS. Nest don’t won’t to work on BUS connection, only on 24V connection and only as on/off for heating, when I change to water it shows me error, weird as the original works fine, any clues how to work out this connection wise to make it work? Would be ok to keep it for heating only but boiler goes on full power and by the time thermostat notice room temp difference, radiators are boiling hot and pressure in the system gets to high as well.

 

[muggles]

Nest doesn't work with Bus connections. If you want a smart stat to work with Glow-worm to modulate the boiler via Bus, use Tado.

If your system pressure is getting too high, your expansion vessel needs looking at

 

[Prezesczwa]

Nest doesn't work with Bus connections. If you want a smart stat to work with Glow-worm to modulate the boiler via Bus, use Tado.

If your system pressure is getting too high, your expansion vessel needs looking at

Thank you for a quick and helpful reply. Now at least I know what to do.

 

[ericmark]

Nest doesn't work with Bus connections. If you want a smart stat to work with Glow-worm to modulate the boiler via Bus, use Tado.

If your system pressure is getting too high, your expansion vessel needs looking at

So you don't consider OpenTherm to be a bus connection? Seems a little odd to include OT1 and OT2 terminals if it does not work, but Nest does seem to do some daft things, I was told it would work with Energenie TRV heads, well the Energenie app will control Nest, but Nest does not it seems control the TRV heads.

 

[Prezesczwa]

So you don't consider OpenTherm to be a bus connection? Seems a little odd to include OT1 and OT2 terminals if it does not work, but Nest does seem to do some daft things, I was told it would work with Energenie TRV heads, well the Energenie app will control Nest, but Nest does not it seems control the TRV heads.

When I connect nest to bus on the boiler and ot 1 and 2 on the nest heatlink, boiler is not responding to nest signals and if I set openterm on nest nest with that connection error shows that no openterm is detected, same on c and on connection

 

[ericmark]

Thanks interesting, I was careful how I put it, as not that impressed with my Nest. My son sang the praises of Nest so I got the same as him, started with the TRV heads (Energenie) and then Nest Gen 3, but my boiler does not modulate, so no OpenTherm. Even if the TRV heads had followed Nest, there is no off-set, and being lower than the wall thermostat they always when heating is on show a lower temperature to Nest, summer when heating not on show the same temperature so not the units it is simply the position.

My hall where Nest is fitted cools slower than other rooms, so any over shoot and I end up with other rooms cool, so in the morning it heats up 0.5°C per hour so it does not over shoot, but when we could go out, the geofencing did work, but of course now not returning to 0.5°C per hour, and an hour after our return if I forgot to alter dial rooms would be cold.

It also seems to have a mind of its own, and after carefully working out a schedule both for TRV and Nest so they worked in harmony, I would find Nest had altered the settings. Although claimed to work with all boilers, with our non modulating boiler it seems I would have been better off with Hive which it seems does connect to Hive TRV heads. It may not have all the algorithms that Nest has, but seems better suited for non OpenTherm boilers. Too late now, not going to change.

But on/off is easy, no worries about comparability, any ebus control and we cross out fingers, I have looked at OpenTherm and if I ever moved to LPG I would want OpenTherm, but my oil bill has been lower than expected, so can't see me moving soon. And I don't like the idea of a ticking bomb in my garden, so safety wise think I will stick with oil.

 

[Prezesczwa]

Thanks interesting, I was careful how I put it, as not that impressed with my Nest. My son sang the praises of Nest so I got the same as him, started with the TRV heads (Energenie) and then Nest Gen 3, but my boiler does not modulate, so no OpenTherm. Even if the TRV heads had followed Nest, there is no off-set, and being lower than the wall thermostat they always when heating is on show a lower temperature to Nest, summer when heating not on show the same temperature so not the units it is simply the position.

My hall where Nest is fitted cools slower than other rooms, so any over shoot and I end up with other rooms cool, so in the morning it heats up 0.5°C per hour so it does not over shoot, but when we could go out, the geofencing did work, but of course now not returning to 0.5°C per hour, and an hour after our return if I forgot to alter dial rooms would be cold.

It also seems to have a mind of its own, and after carefully working out a schedule both for TRV and Nest so they worked in harmony, I would find Nest had altered the settings. Although claimed to work with all boilers, with our non modulating boiler it seems I would have been better off with Hive which it seems does connect to Hive TRV heads. It may not have all the algorithms that Nest has, but seems better suited for non OpenTherm boilers. Too late now, not going to change.

But on/off is easy, no worries about comparability, any ebus control and we cross out fingers, I have looked at OpenTherm and if I ever moved to LPG I would want OpenTherm, but my oil bill has been lower than expected, so can't see me moving soon. And I don't like the idea of a ticking bomb in my garden, so safety wise think I will stick with oil.

I wouldn’t mind using nest on on/off setting with my boiler as hot water is set to right temp anyway, but the problem was that nest did not record changing temp quick enough causing rads to get very hot, you might say change the position of nest but even one meter from radiator took it ages to record temperature change in the room. When I first set it I hold nest in my hand for a while and it showed me 24 degrees temp, took it around an hour to go back to room temp.

 

[ericmark]

Not tried that, but yes that would cause the problem. I have had a boiler problem so not really set the lock shield valves yet, in mother house I did, and I found the radiator rarely hit full temperature, the TRV controlled them well.

 

[muggles]

So you don't consider OpenTherm to be a bus connection? Seems a little odd to include OT1 and OT2 terminals if it does not work, but Nest does seem to do some daft things, I was told it would work with Energenie TRV heads, well the Energenie app will control Nest, but Nest does not it seems control the TRV heads.

OpenTherm is a different language to Vaillant/Glow-worm BUS

 

[ianmcd]

As @muggles says OT and bus are two different things they wont communicate, and this has absolutely nothing to do with your pressure problems

 

[Prezesczwa]

I know this is about a nest thermostat originally but I wanted to ask if anyone knows if my boiler glowworm easicom 24 will work with Hive smart thermostat as nest did not.

 

[muggles]

Not over eBUS, no. It'll work as an on/off thermostat just as Nest would

 

[ianmcd]

nest did not.

Nest would you just wired it wrong, Nest will only work as an on off Thermostat with your boiler