Minimum requested flow water temperature
Hello,
Does anybody have any measurement what is the lowest flow temperature value the Tado thermostat may request from a boiler connected via OpenTherm ?
Does it go below 30 C ?
Is it affected by any means if you configure that you have UFH in the system ? (as with UFH you may use really low flow temperature)
Answers
-
It can’t be set below 30c on the Tado pro app. It may be a limitation of Opentherm or tado just deciding that most boilers won’t be able to fire below that.0
-
@johnnyp78 : that is the maximum value the thermostat may request, is it not ?
Let's imagine I set 40 C as the maximum and I can see that the flow temp really does not go above that. However depending on the weather or room conditions the thermostat may request lower temp than 40, e.g. 35. I am curious what is the minimum temperature it can request ?
Your point absolutely makes sense, requesting below 30 does not make sense and it would force the boiler to cycle. However I have the feeling that it sometimes requests below 30, I just do not have the proper equipment to check the communication between the thermostat and my boiler.
0 -
Good point. I would think minimum flow temperature might be decided by Tado telling the boiler to go to its minimum flow level, but I couldn’t say for sure.0
-
I expect there are too many unknowns to answer this. There’s the boiler and what functionality it advertises. Then how Tado choose to drive the boiler. Nothing stopping them using relative modulation levels even.
I can understand there’s argument that insufficient delta T can’t really do any viable heating of the home. Whether Tado have this in their code, we won’t know. I’m not aware of anything written into, say V2.2, that would make a low value request invalid.
There are clear bits in the protocol where the boiler can advertise power and minimum output levels. Again, just guesswork what happens here without proper data.
0
