Strange boiler behavior

[juan]

Hi all,

I ordered the Opentherm gateway as a kit. After assembling the kit I measured al voltages and currents and everything seems to be OK. I loaded firmare v4.2 to the PIC. Then I connected the OTGW to my Honeywell Chronotherm Vision Modulation thermostat and to my Intergas Kombi Kompakt HR 28/24 boiler. The gateway seems to work well. No errors so far but the graph shows a strange behavior of the boiler. The temperature drops to zero once in a while (see picture). I don't know if it is an error in the boiler (sensor) or in the gateway or a timing problem in the software or something else.
I searched the forum for simular problems but I can't find anything similar (so far).

Does someone knows what this behavior is caused by?

Thanks in advance.




In case the image doesn't show up here is dropbox link: https://www.dropbox.com/s/6qgnv8jtmfcnf ... e.jpg?dl=0

[hvxl]

Just look at the logs around the time where you see a drop in the graph and you should be able to tell if it's the boiler that's reporting the value, or otmonitor interpreting something incorrectly.

[juan]

Thank you Schelte for your reply. I did look at the log but I didn't yet know where to look for
I'll try that as soon as I'll be home.

[hvxl]

The figure that drops to zero is the boiler water temperature. You can click on the graph close to such a drop to get the approximate time of the occurrence. Then go to the statistics tab and select "Boiler Water Temperature". That will highlight the reports for that DataID in the log tab. Scroll the log tab to the time you found from the graph. Then look for highlighted reports from the boiler around that time (you'll first find a Read-Data request from the thermostat that always has a value of 0. That's OK). If you find a Read-Ack message with a value of 0, then the boiler is really reporting a temperature of 0. If you find something else, let me know so I can fix otmonitor.

[juan]

I finally found the time to reconnected the gateway to the CH system and when the boiler temperature in the graph dropped to zero again I looked at the log file and found the following data:

Code: Select all

13:56:16.905251	T10013900	Write-Data	Control setpoint: 57.00
13:56:17.045587	BD0013900	Write-Ack 	Control setpoint: 57.00
13:56:17.451276	T00090000	Read-Data 	Remote override room setpoint: 0.00
13:56:17.459070	R00780000	Read-Data 	Burner operation hours: 0
13:56:18.355967	T80190000	Read-Data 	Boiler water temperature: 0.00
13:56:18.367223	R80190000	Read-Data 	Boiler water temperature: 0.00
13:56:18.465178	BC0193B00	Read-Ack  	Boiler water temperature: 59.00
13:56:18.473060	A40190000	Read-Ack  	Boiler water temperature: 0.00
13:56:18.886417	T00090000	Read-Data 	Remote override room setpoint: 0.00
13:56:18.897851	R007B0000	Read-Data 	DHW burner operation hours: 0
13:56:19.073477	B407B07FF	Read-Ack  	DHW burner operation hours: 2047
13:56:19.080162	AC0090000	Read-Ack  	Remote override room setpoint: 0.00
13:56:19.432285	T80640000	Read-Data 	Remote override function: 00000000
13:56:19.436951	R00740000	Read-Data 	Burner starts: 0

What do the R and A codes at 13:56:18 mean?

[hvxl]

What do the R and A codes at 13:56:18 mean?

That's explained on the web site.

This is very interesting. The request before the Boiler water temperature has been replaced by an alternative message, but the boiler doesn't provide a response on that. Then on the next message (the Boiler water temperature request) the gateway apparently still has some state left over from the previous incomplete communication. That causes it to report that it's sending a replacement message to the boiler, even though it's exactly the same as what the thermostat requested. Because it thinks it sent a replacement message, it then also clears the data value it receives from the boiler. This causes the drops you noticed in the graph.

So there's probably a bug in the gateway firmware rather than in otmonitor. I will have to investigate what exactly is going wrong and what to do about it. Thanks for reporting this. I'm glad you didn't just shrug your shoulders and ignored this occasional drop.

[juan]

Thanks for your answer Schelte.

If I can help you out by sending a log file please let me know.

[hvxl]

Thanks for the offer, but that probably won't be necessary. I have been able to reproduce what you saw on the simulator. My suspicion was correct, there was some state left behind from the unanswered replacement message.

You could help me out by trying firmware 4.2.1, which will hopefully fix the issue. Please let me know either way.

[juan]

Works like a charm now! (see picture).



or link: https://www.dropbox.com/s/fj1e978qjf2cz ... 9.jpg?dl=0

Code: Select all

OpenTherm Gateway V4.2.1

14:41:00.114362	BC000030A	Read-Ack  	Status: 00000011 00001010
14:41:00.519982	T10013300	Write-Data	Control setpoint: 51.00
14:41:00.722626	BD0013300	Write-Ack 	Control setpoint: 51.00
14:41:01.065992	T00000300	Read-Data 	Status: 00000011 00000000
14:41:01.222066	BC000030A	Read-Ack  	Status: 00000011 00001010
14:41:02.002019	T80190000	Read-Data 	Boiler water temperature: 0.00
14:41:02.126744	B40193300	Read-Ack  	Boiler water temperature: 51.00
14:41:02.532536	T00000300	Read-Data 	Status: 00000011 00000000
14:41:02.641548	BC000030A	Read-Ack  	Status: 00000011 00001010
14:41:03.063309	T00000300	Read-Data 	Status: 00000011 00000000
14:41:03.250010	BC000030A	Read-Ack  	Status: 00000011 00001010
14:41:03.609124	T00000300	Read-Data 	Status: 00000011 00000000
14:41:04.529059	T00000300	Read-Data 	Status: 00000011 00000000
14:41:04.653883	BC000030A	Read-Ack  	Status: 00000011 00001010
14:41:05.059811	T00000300	Read-Data 	Status: 00000011 00000000
14:41:05.149967	BC000030A	Read-Ack  	Status: 00000011 00001010
14:41:05.586974	T10013300	Write-Data	Control setpoint: 51.00
14:41:05.766363	BD0013300	Write-Ack 	Control setpoint: 51.00
14:41:06.135921	T801C0000	Read-Data 	Return water temperature: 0.00
14:41:06.142263	R007B0000	Read-Data 	DHW burner operation hours: 0
14:41:06.276379	B407B07FF	Read-Ack  	DHW burner operation hours: 2047
14:41:06.281178	A701C0000	Unk-DataId	Return water temperature: 0.00
14:41:06.666479	T80190000	Read-Data 	Boiler water temperature: 0.00
14:41:06.775434	B40193300	Read-Ack  	Boiler water temperature: 51.00

Thanks for solving this problem so quickly

[hvxl]

Thanks for testing.

(Tip: Don't use jpg format for screen shots, it looks terrible. GIFs or PNGs are much more suitable)