Request: exhaust temperature

[Pajuris]

My gas boiler: Viessmann Vitodens W-100 B1KC 26 kW has exhaust temperature sensor. Would be great to see this information in opentherm gateway...

[Laxilef]

Where can this be useful? I didn't add this sensor because I don't see where it can be used.

[Pajuris]

It's important for gas consumption. If exhaust temperature is high (50-55 C or more), condensing gas boiler not working in condensing mode.

[Laxilef]

Hi @Pajuris Pls test it

[Pajuris]

Hello Installed 1.4.0-rc.18 but no new sensors appears... I must compile manually? And... my previos version was 1.4.0-rc.14. So it worked much better. RC.18 version runs much slower: for example modulation value appears only ~30-40 seconds after real flame turn on. I could see DHW flow rate 5-7 l/min and flame on, but modulation show 0% another 20-30 seconds.

[Laxilef]

Yes, you need to compile from source.

And... my previos version was 1.4.0-rc.14. So it worked much better. RC.18 version runs much slower: for example modulation value appears only ~30-40 seconds after real flame turn on. I could see DHW flow rate 5-7 l/min and flame on, but modulation show 0% another 20-30 seconds.

Can you upload the logs?

[Pajuris]

OK, compiled and installed... OpenTherm Gateway Exhaust temperature and OpenTherm Gateway Heating return temperature appears. OpenTherm Gateway Heating return temperature always show 0. OpenTherm Gateway Exhaust temperature show wrong values 0.1-0.2 C What logs do you need? From where I must take it?

[Laxilef]

OpenTherm Gateway Exhaust temperature show wrong values 0.1-0.2 C

Fixed it in the last commit. Please recompile the firmware and test it now.

What logs do you need? From where I must take it?

Connect to ESP using telnet or serial port and save the logs.

[Pajuris]

OK, Exhaust temperature seems to work corectly. Logs attached. ZOC2403_Telnet Connection Example0109.log ZOC2403_Telnet Connection Example0107.log

[Laxilef]

Thanks for the tests. Looking at the logs, the data is updated without delay. I don’t see random INVALID or TIMEOUT response statuses. Except ID 28, it is not supported by your boiler.

for example modulation value appears only ~30-40 seconds after real flame turn on. I could see DHW flow rate 5-7 l/min and flame on, but modulation show 0% another 20-30 seconds.

In fact, the modulation can be 0% and this does not mean that the flame does not burn. 0% is the minimum level. It would have been more correct to make the minimum level 1%, but the manufacturers decided otherwise.

[Pajuris]

When DHW turns on (mixer is full open), boiler modulation when I look on boiler display, is more than 50 % and changes. But modulation in HA show 0 % and does not changes about 30 seconds. Anyway, I will do more tests tomorrow (maybe I will try to downgrade firmware to 1.4.0-rc.14) Also... heating temperature, when DHW turns on, HA shows about 60 degrees, after few seconds. And it can not be 0, 5 or 10 % modulation. It's must be and off course is, much more.

[Laxilef]

Try looking at these parameters on the portal page, the data is updated there every 10 seconds

[Pajuris]

On portal page modulation is 0 % too. When portal start showing modulation value, after few secons value appears and on HA.

[Laxilef]

Well, I don’t know why the boiler can send data with such a delay. In the logs you can see the "raw" data of communication between the ESP and the boiler. In the response, you should be interested in the first 16 bits.

[Pajuris]

OK... 1.4.0-rc.14 version modulation value appears with delay too. It's Viessmann boiler problem. Thanks Laxilef for new, exhaust value sensor. Good job.