Home Automation Domotica Forum Europe, Bwired Forum

Greeting to whoever reads this.

I've come across a possible opentherm conflict bewteen my boiler and honeywell programmer and would like a bit of advice from people in the know.
Programmer in question is a Honeywell sundial rf pack 5 honeywelluk.com/products/Systems/Sundia ... F2-Pack-5/ and boiler is a Ferroli Modena He 32.

Problem that I'm having is that if I set the Dhw temperature to 55deg on the boiler, the setting gets altered to 40 deg by the programmer and I have no way of adjusting it on the programmer. It states in the installation manual that setting the Dhw on this model is not supported, but it's still sending a write command of 0 deg to the boiler. Should it still be sending dhw write commands to the boiler?

I've contacted honeywell and the opentherm association but guess I won't get a reply from them until early next week.

Logs captured with opentherm gateway 3.4
Opentherm gateway in monitor mode:
Opentherm gateway in monitor mode:

19:18:41.867986 T00000300 Read-Data Status: 00000011 00000000
19:18:42.755169 T10380000 Write-Data DHW setpoint: 0.00 ** programmer should not be sending this??
19:18:42.886398 BD0380000 Write-Ack DHW setpoint: 0.00
19:18:43.739455 T10393700 Write-Data Max CH water setpoint: 55.00
19:18:44.626434 T10393700 Write-Data Max CH water setpoint: 55.00
19:18:44.707285 BD0393700 Write-Ack Max CH water setpoint: 55.00
19:18:45.610052 T00000300 Read-Data Status: 00000011 00000000
19:18:45.713524 BC000030A Read-Ack Status: 00000011 00001010
19:18:46.592192 T90013700 Write-Data Control setpoint: 55.00
19:18:47.477801 Error 03
19:18:48.354632 T90013700 Write-Data Control setpoint: 55.00
19:18:48.443264 B50013700 Write-Ack Control setpoint: 55.00


Opentherm gateway in gateway mode:

00:08:41.135354 T80190000 Read-Data Boiler water temperature: 0.00
00:08:41.246895 B40193600 Read-Ack Boiler water temperature: 54.00
00:08:42.026317 T80000200 Read-Data Status: 00000010 00000000
00:08:42.167761 B40000200 Read-Ack Status: 00000010 00000000
00:08:43.000475 T10380000 Write-Data DHW setpoint: 0.00 ** programmer should not be sending this??
00:08:43.013491 R90383700 Write-Data DHW setpoint: 55.00 ( gateway sent this command, not programmer)
00:08:43.149035 B50383700 Write-Ack DHW setpoint: 55.00
00:08:43.987445 T10393700 Write-Data Max CH water setpoint: 55.00
00:08:44.132857 BD0393700 Write-Ack Max CH water setpoint: 55.00
00:08:44.958187 T10010A00 Write-Data Control setpoint: 10.00
00:08:45.465261 BD0010A00 Write-Ack Control setpoint: 10.00
00:08:45.938171 T80190000 Read-Data Boiler water temperature: 0.00
00:08:46.030222 B40193600 Read-Ack Boiler water temperature: 54.00

Am I correct in thinking that the programmer might be faulty?

Kind regards

I would agree that the thermostat should not send a DHW setpoint write message with a value of 0. On the other hand I would also expect the boiler to respond with Data-Invalid instead of just acknowledging the request and using its minimum value, which apparently is 40 degrees.

I think I have a related problem with the ST9520 controller supplied with the Sundial pack 5.

Can you tell me whether you have this problem all the time or only after boiler initialisation? Also, have you had a reply from Honeywell?

I have a Remeha Avanta Plus 24s running under OpenTherm control through the ST9520.

If there is a power supply interruption, planned or unplanned, at a subsequent DHW production phase and later only warm hot water is produced because the flow temperature does not exceed 60 deg. I can overcome this by returning the boiler to factory defaults and then adjusting its parameters to my requirements. I should mention that when the fault exists no boiler parameter differs from its set value before the power interruption.

Thanks