Purchase Tado Wireless but no Opentherm - effect on modulation?
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Boiler modulation and the modulation that Tado does with digital connections are two different things. Modern gas boilers use internal modulation regardless of what’s connected to them. Tado does pseudo modulation on a switched relay connection by cycling the boiler.0
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thank you. I seem to be getting different replies from the Tado Facebook group I joined. they say that 'Worcester greenstar 4000 doesn’t work with Tado opentherm for modulation. Will work with on off functionality. The boiler itself modulates with the flow temp' - also I can have the 'Worcester 4000 with the non EU version with no issues' BUT THEN THIS 'This boiler uses a Ems bus protecol. (Found in boiler manual) tado can use multiple protecols. Ems is one of them. To use this digital protocol. U need the EU version of tado. This way you will benefit the modulation control option of tado' and this 'Tado are aware of the EMS2 issue and I believe they have considered developing a protocol, but resources and time required is significant. I keep
looking for updates but nothing so far. (BTW. I have developed a workaround, but it involved developing my own modulation algorithm through Home Automation).' then finally this 'sorry to say the Worcester Bosch 4000/8000 series uses EMS2 which is incompatible with Tado. You will only have on/off control via 240V.'!!! HELP!
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So they’re telling you you can’t use a digital connection with your boiler because Tado doesn’t support it. Use switched relay then, like they’re suggesting. As I said, tado will do pseudo modulation with that anyway.0
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what does switched relay mean please?
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A traditional room thermostat controls the temperature by switching a relay that turns the heating on or off. A digital connection like Opentherm or ems allows the thermostat to control the room temperature by telling the boiler to modulate the boiler flame.0
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ah thanks that makes sense. so it is more efficient to have opentherm as it is more sensitive and will not drop and then rise.
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It’s debatable. It’s probably more efficient than cycling the boiler but as you don’t have that option available to you I wouldn’t worry about it, as I have said tado imitates modulation with switched relay anyway.0
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thank you I will not be able to fit it myslef and my boilerman says Hive is better but I really wanted the Tado for some reason!
GOT THIS MESSAGE FROM THE TADO TECHNICAL SUPPORT;
Thank you for your message. The Worcester Greenstar 4000 boiler doesn't support OpenTherm for modulation with tado°. The only way to connect tado° to this boiler is through the relay (on/off switch) interface, without modulation.
The UK version of the Wireless Receiver only supports relay (on/off switch) interfaces, therefore, this device would work with your boiler. The EMS protocol of your exact boiler is also unfortunately not supported.
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Can I just caution you against making an investment in Hive TRVs. I speak from personal experience in saying they are hopeless and their HOD (Heat On Demand, the equivalent of tado's calling for heat) does not work properly. Have a look at some Hive forums for confirmation of this, for example:
The rest of the Hive system ("bridge", room stat / programmer, "wireless receiver") is OK and better, RF wise, than tado I think . . .
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