SAT not adjusting t_set properly? Autotune buffering and oscillating boiler temperature (ESPHome OpenTherm gateway)

[elmensy]

Hello fellow SAT'rs,

First of all, always nice to see an integration like this in/for the HA community! Keep up the good work! I came across the SAT integration while looking for a way to replace my Tado X setup with something I can control myself, instead of relying on cloud services and subscription models.

After ordering and receiving an Aqara W600 TRV and a DIYless Thermostat 3 for a test setup, I started implementing the system. The TRV is configured as a Zigbee device and connected to Versatile Thermostat, allowing me to dynamically compensate for the internal sensor error. The DIYless device is flashed with ESPHome and configured with the minimal YAML configuration from the readme. The device only works as a gateway and does not have a climate entity (e.g. thermostat or thermostat with PID). The OT gateway is connected with my Intergas HRE boiler.

Side quest(ion): Would it be possible (and preferable) to also have a climate entity on the gateway device? The minimal YAML configuration indicates that t_set needs to be a number and wouldn’t that cause a conflict? It would be nice to have a workaround or fallback to heat the rooms via the gateway device in case Home Assistant or Wi-Fi is down.

I configured SAT as described in the README, but I’m encountering some unexpected results. First of all, the autotune for the overshoot value was not successful. I don’t receive an error, but it keeps buffering for more than 1.5 hours while enabling my boiler. After reading about the manual method, I decided to try that approach instead. However, if I understand the information in thread #36 correctly, the modulation needs to settle first. The result I obtained is shown below, where the water temperature keeps over- and undershooting.

Another observation is that the modulation of my boiler always starts with a small slope and then, in most cases, increases quite aggressively. I assume the expected behavior is that SAT varies the temperature setpoint (t_set)? However, when looking at the logs of my OpenTherm Gateway, I observe that SAT sends the same water temperature setpoint to the boiler roughly every 10 seconds, so something is happening there.

Some other observations during testing:

• If I set the SAT climate entity to heat then ch_enable is turned “on”. As a result, my boiler will start pumping/heating regardless if the setpoint temperature of the SAT entity is above the room temperature.
• I used to encounter many problem states with the Control Setpoint Synchro. After enabling the dynamic setpoint option and setting the controller version to “boiler temperature,” the situation improved.

When looking through the debug log I also continuously see a debug message indicating that the SAT component is looking for the dedicated OpenTherm entities of the ESPHome component. I’ve included a small snippet below. I’ve already checked the entity names and re-added the ESPHome device. What could be causing this?

My setup:
Aqara TRV > Versatile Thermostat integration > SAT integration > DIYless thermostat 3 as ESPhome OpenTHerm gateway > Intergas HRE boiler

My SAT config:

What could be causing this unexpected behavior, and how could I resolve it? I have already read many discussions here and on the Home Assistant discussion page, but without finding the golden answer. Any help would be greatly appreciated.

[sergeantd83]

Hi @elmensy. Intergas boilers do not support maximum modulation management, which makes them a bit tricky to handle. For your boiler in particular, it is better to use the releases/thermo-nova branch.

We have made several improvements to support boilers both with and without maximum modulation management.

To update to this version, go to Developer Tools → Actions and run:

action: update.install
target:
  entity_id: update.smart_autotune_thermostat_update
data:
  version: releases/thermo-nova

This release is still experimental, but I hope it helps resolve your issue.

[elmensy]

Hey @sergeantd83 thanks for your fast reply. I updated it to the thermo-nova release and ran it for an hour-ish. It still over and undershoots without real change in the control values. What in essence is the expected behaviour? Is this a change in the setpoint value of the requested water temperature depending on the error?

I also ran the debug monitor and I at least see that the messages regarding the unique_id are gone. The resulting log of the process can be seen below. Here you an also observe that the control values (except for the PID values) do not really change.

Below my sensor overview of SAT:

Then some other questions:

• The "Heating Curve Recommendation" sensor. Is this related to a recommendation to increase the heating curve coefficient or is this just unrelated?
• I see you added "Pressure Health" function (Nice!). For this to work I guess I need to rename the water pressure enitity in my device similar as with the other enitities?
• Why is the PID value so high (see pictures above)?
• "Cycle Health" states that there is problem. What could be triggering this? is this the continuous over and undershoot?
• In the minimal YAML configuration example there are definitions for "min_mod_level" and "max_capacity". However, these are not defined in the ESPHome Opentherm definitions (https://esphome.io/components/opentherm/). Is this coming from some older obsolete definition/version or are they mapped to something different?

Thanks in advance!

[sergeantd83]

Can you please use a higher Maximum Setpoint value in the general settings. Something like 55°.

[elmensy]

I increased the max setpoint back to 65 degrees and set the room temp setpoint to something that is able to reach. In addition, I changed some setting on my boiler side to make it less aggressive (lowered max power and disabled boost mode). See the resulting curve below. Still the over and undershoot behaviour is visible. I did see (not visible in the picture below) that t_set was lowered when the room temperature was approaching the requested room temperature. I only saw this once and did not see this behaviour the second try.

Did you perhaps also have some time to answer my questions of my last comment? In addition, does ch_enable keeps on even if you reached your room setpoint? If so, why is this since, in my case, my boiler keeps heating and pumping the water even if there is no real request from my radiator.

[elmensy]

I did some tweaking of my boiler and reduced (among others) the maximum power. This slightly reduced the amplitude of the oscillation while still being able to heat the rooms. The cycle with under and overschoot is still there but I guess that this is a result of the way Intergas controls its heating.