[Release] OpenTherm Max Flow Temperature setting
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@GrayDav4276 it’s definitely responding to temp changes made in the Tado pro app now. Might have just needed a restart first.0
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@GrayDav4276 @johnnyp78 I found that setting the Max Flow to the default 80˚c and let the flow rate change to what it's needs, found to give me the best results, I have only seen it hit 80˚c once and was when my outside hit -3, and was a 3 bar demand in heat, and it only lasted 10 mins, then started to modulate back down to 45˚c, most of the time my current flow rate is at 30-36˚c, so IMO if your using OpenTherm I see NO benefit in redicing the Max Flow Rate, in fact it makes things worse. If you use "Relay" and "Weather Compensation" I can see it helping a ot more.
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This is what I want to test. Up until now I’ve been fine with the max flow temp set to 55c. If Tado can stay below that unless it’s extremely cold I’m fine with turning up the max flow temp. If it keeps ramping up to 80c, back down the max flow temp goes.0
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@johnnyp78 might take few days to learn new flow temps. changing the Max Flow messes with the AI.
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@johnnyp78 here is yesterdays graph for my media room.
as you see bumping 1.5˚c at -2 outside caused a 2 bar demand, it would only have had about 42-48˚c flow temp temp for about 20 mins, before modulating back to normal around 32˚c.
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Yeah, I’ll give it a few days while it’s cold. I know it needs to update its PID stats. Not a fan of the scorching hot radiators at the moment though, I liked having ones that were warm to the touch!0
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Very strange, I checked again yesterday thinking "you never know", and the max. flow temp. was set at 62°C after all, which is the test value I had input on November 30th. So apparently it does work, but it comes with a ridiculously long delay.
I've set it back to 60°C yesterday, but I've just checked this morning, and it's still at 62°C.
So I guess I'll have to give it a couple of days again before the value changes.
Makes it pretty useless when reacting to a cold snap however: by the time the setting has changed on your boiler, outside temps could have risen again.
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I was actually referring to the setpoint being sent from the thermostat to the boiler, not the actual water temperature itself. That setpoint can be read out on my boiler.
That has been 60 degrees (at full throttle) for 5 years (since I installed my tado), and now it suddenly is 62 degrees, exactly the temp. I had put in the pro app 11 days ago.
That's a bit too much to be a coincidence.-1 -
@GrayDav4276 it was when I noticed my current flow was getting above my max flow (at the time 65˚c, when max flow was 60˚c) awhile ago, Jurian replied to me with
"@andyblac Happy to hear it, small tolerance is completely normale due to sensor positioning and PID control of the boiler itself when it comes to how much gas should be burned."
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How frequently does the server read out the current flow temperature from the device ?
I am referring to the "Updated: X minutes ago" under the "Data can be read from the boiler" section.
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I have set the max flow to 55 degrees so why the hell does the boiler speed up to 80 degrees even though both on the front panel (just in case) and in the app I have it set to 55 degrees?
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That is, as I understand it, using the installer app will not change the flow settings of my Ideal Combi Plus boiler. Just manual option with a knob.
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Did you try cutting the power after changing the settings? On my ideal boiler if you don’t do that, the max flow temp setting takes about a day to change.0
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@Alinoe , switch boiler and tado ext off for approx 30 mins, then switch back on.0
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This is a very interesting read, I am about to swap over from Hive to Tado with Opentherm on a Vaillant ecotech 28 pro boiler using the ebus. My daytime temps is set at 20c on the Hive between 6am and 10pm I am finding the temps are overshooting 20c is the Tado have smooth and steady temps?
What does a Tado Openterm temps chart look like?
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My Tado on Ecotec 938 via eBUS always overshoots to start with by up to 0.5oC however once at temp it maintains temperature at todays temps at +\- 0.1 to 0.2oC according to the graph. However things like how you are using the system and anti cycling times will play it’s part, so it could be worse if the boilers oversized.0
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Hello,
I have been reading all this trail with great interest.
I have an Atlantic 4124 Opentherm connected to Tado and I having some issues.
The first one it that the max Temp for Hot water is set in the App at 55° and the boiler heat the water at 60°.
Is there a way to sniff the Opentherm communication between Tado and a boiler.
Is there any log that can be look at? Maybe in the bridge?
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Because OT is not a bus protocol, you’d need to provision a gateway to see the communication.
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Is this feature available on Tado web API? As long as the installer app can set max flow temperature - there is an endpoint for that I guess. Is there a chance that it becomes public? Then it'd be possible to adjust the max flow temperature by season or weather automatically.0
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there is:
just use Select boiler model & check setup status – tado° installers in browser with dev tools open.
you can see there is a PUT call on https://my.tado.com/api/v2/homeByBridge/IBxxxxxxxxxx/boilerMaxOutputTemperature?authKey=xxxx
with payload: {
"boilerMaxOutputTemperatureInCelsius": 70
}
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Dragging up an old thread, but noticed this today. Nice to have this control in the main app now…
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so now I have to pay for opentherm to work? what
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To be fair this is a new feature, it seems that Tado now does actual weather optimisation rather that just weather adaption which was just adjusting for demand rather than outdoor temperature.0
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so now I have to pay for opentherm to work? whatNo, you misunderstand the feature.
Free version:
To be clear, you can set a static maximum flow temperature for Opentherm in the free version. Both V3+ (and older) and tado X. When Opentherm is modulating, it will produce lower temp water than your set maximum flow temperature. The setting is the temperature cap which the boiler should not exceed. This is a setting we've had for years (in the pro installer tado app and via support). The only thing that changed there is that is now also available in the 'normal' tado app. The is the normal setting that Opentherm boilers themselves and other Opentherm thermostats also offer. The only thing that has changed is that you now have easier access to this setting in our app.
In the free version we modulate the requested water temperature based on:
- the heat request in the room(s)
- the maximum flow temperature
Example of static value in the free version: maximum flow temperature manually set to 70 degrees.
Thermostat has a 100% heat request —> boiler will produce 70 degree water.
Thermostat has a 50 % heat request —> boiler will produce 55 degree water
(the 50% and 55 degree numbers are merely made up examples to illustrate how the principle works, actual numbers depend on the boiler and its implementation of Opentherm)Auto Assist & Automated optimization enabled:
The significant change is that we added a feature for Auto Assist subscribers for a dynamic heat curve. Here you can still select a maximum flow temperature, but this will only be the actual max flow temp on really cold days.
In the Auto Assist & Automated optimization enabled version we modulate the requested water temperature based on:
- the heat request in the room(s)
- the maximum flow temperature
- the outside temperature
Example of automated maximum flow temperature, set to maximum 70 degrees.
Outside temperature is -15 degrees C (=really cold).
Thermostat has a 100% heat request —> boiler will produce 70 degree water.
Thermostat has a 50 % heat request —> boiler will produce 55 degree waterNow, outside temperature is +15 degrees C (=not super cold)
Thermostat has a 100% heat request —> boiler will produce 55 degree water.
Thermostat has a 50 % heat request —> boiler will produce 40 degree waterAgain, the numbers I used are made up and merely here to demonstrate the principle.
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@Rob really like the update and it did convince me to get auto assist again.
One thing that would improve this further is to be able to be able to select variations on the heat curve.
Most boilers with weather compensation controls allow you to set a number for the heat curve, so if your home is efficient with large radiators you can run the system cooler so a less aggressive curve. An older home with smaller emitters and poor insulation might need slightly higher temperature curve. Typically 1 runs cooler and a higher number will run hotter.0 -
@mojomoomoo It kind of already allows you to do this, right? Depending on the type of insulation of your home, you set the maximum flow temperature to a relatively high temperature (poor insulation and/or low capacity radiators) or lower (better insulation and/or higher capacity radiators). Then the optimization feature will optimize the heat curve, with the maximum being the temperature you've set and thus taking into account your home efficiency.
Am I overlooking something?
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@Rob all that does is limit the highest temperature. 10°C today outside and the max flow adjusted to 52°C looking at most manufacturers heat curves, at 10°C systems might run as low as 2x°C but depending on your chosen curve setting could be as high as 65°C. My alpha boiler for example using a sensor has 9 curve settings allowing you to find the sweet spot for your home.
By using a heat curve with lower temperatures a condensing boiler can run much closer to it's optimal efficiency.
I've not seen TADO drop my flow temperature below 52°C even on a 15°C day with very little demand.0
