Opentherm Gateway 4.0 alpha/beta testers wanted

[DatafoxChris]

Testing the 4.0b4 firmware, i still don't get DHW setpoint in PS=1 reports, while in firmware 3 this worked OK.

Using Nefit boiler with opentherm converter.

00:04:50.105120 T80383C00 Read-Data DHW setpoint: 60.00
00:04:50.197003 B70383C00 Unk-DataId DHW setpoint: 60.00
00:04:50.212662 A40385000 Read-Ack DHW setpoint: 80.00

00:18:10.089541 PS: 1
00:18:10.239417 00000000/00000000,10.00,00000000/00000000,0.00,0/0,15.00,0.00,1.30,19.76,59.60,50.50,10.90,56.90,0/0,0/0,0.00,72.00,8869,0,0,59136,14684,0,0,0

[DatafoxChris]

My (new) EMS-OT converter seems to support this. I can turn a knob on the boiler to select DHW setpoint. When i change the knob and view the settings in the thermostat later, then the thermostat knows the actual setting of this DHW setpoint knob on the boiler. Same goes for the max CH setpoint knob which is reported correctly.

Still the gateway reports 0.00 as DHW setpoint in the PS:1 reports... the gateway isn't in monitor mode and reports all other important details correctly.

[hvxl]

Nothing has changed in that area of the firmware because I was not aware there still was a problem. You never indicated that my previous suggestion did not help.

The B70383C00 message (Unk-DataId DHW setpoint: 60.00) you showed indicates that the opentherm converter doesn't support the DHW setpoint message, as I expected. So returning 0 in the PS=1 report is quite reasonable, I'd say.

However, if the thermostat is able to display the correct DHW setpoint, it may be interesting to figure out how it gleans that information. To attempt to do that, can you provide a log from a power-on of the gateway until your thermostat reports the DHW setpoint you have set at the boiler?

[DatafoxChris]

Thank you for your answer, sorry for not responding, i am wiling to help improve the gateway firmware and have already sent the logfile to you.
The gateway starts the DHW setpoint at 80, and after some time the DHW setpoint is changed to 60 as configured on the first boiler knob, and the Max CH water setpoint is changed to 70 (starts at 90) as configured on the second boiler knob.

I think this happens in the logfile at this moment:

18:15:15.521048 B40000200 Read-Ack Status: 00000010 00000000
18:15:15.968052 T80383C00 Read-Data DHW setpoint: 60.00
18:15:15.971982 R00770000 Read-Data DHW burner starts: 0
18:15:16.049123 BC077E71D Read-Ack DHW burner starts: 59165
18:15:16.059043 A40385000 Read-Ack DHW setpoint: 80.00
18:15:16.492273 T00395A00 Read-Data Max CH water setpoint: 90.00
18:15:16.585403 B40394600 Read-Ack Max CH water setpoint: 70.00

[andre_OT]

Isn't it so that the Nefit boiler has a physical button for setting the boiler water temperature and warm water temperature? I wonder whether it is software adjustable?

I know practical situations nefit boilers are externally controlled by a 0 .. 10V signaal based on power , but not by changing the boiler temperature...

[DatafoxChris]

Yes my nefit boiler has turn-knobs for the two settings.
I don't want to overrule these two setpoints, I just want them to display correctly through the OTGW on my tablet-thermostat

[andre_OT]

DatafoxChris,

I will call the Nefit support line tommorow to see if that is possible.
If I have the time and don't forget it...

I will ask if the EMS-OT converter can pass / report the setpoints for cv and hot water from the UBA2/3 (Smartline)

[hvxl]

DatafoxChris,

I don't see anything in the logs you supplied that could explain how the thermostat might get a DHW setpoint from the boiler.

For this test you had the DHW setpoint at the boiler set to 60 degrees, right? If you set it to something more unusual, like 58 or 62, does the thermostat correctly pick that up too, or does it simply always settle on 60?

The weird thing is that the EMS-OT converter does return a Max CH water setpoint (of 70), but at some point the thermostat starts putting 90 degrees in the data value of its request. Where does that come from? Are these not values configured on the thermostat somewhere?

[DatafoxChris]

Yes, the CH setpoint is reported correctly on the OTGW, only the DHW setpoint is not. When I use firmware 3 it works as it should.
As I have some time to test this now, I will change both knobs to an unusual setting, and check the setting on the thermostat.
I use this thermostat: Honeywell Chronotherm Vision Modulation with green display (TH8110M1003), and I check the setpoints in the installers menu.

[DatafoxChris]

Andre_OT: thank you for calling the support line, I hope they can tell you what is supported and what is not.

hvxl,
I think my test has made some things a little more clear:
I cannot find any way of changing the DHW or CH setpoints in the thermostat, these values are only shown and cannot be edited.
The thermostat seems to want to set the DHW setpoint to 60 degrees, and this by accident is the same setting as I had set on the DHW knob on the boiler.
Using firmware 3, the PS=1 command reported the DHW setpoint requested by the thermostat (60), but not the DHW knob-value from the boiler.
Using firmware 4, the PS=1 command always reports 0 degrees for the DHW setpoint, regardless of the value sent by the thermostat.
Using both firmwares, the CH setpoint is always the value configured on the boiler knob, so the EMS-OT converter does report this correctly.

Still I think the PS=1 command should report 60 degrees for DHW setpoint, although this value is not communicated to or coming from the boiler.

From the logs:

FW 4:
22:50:16.453568 T80383C00 Read-Data DHW setpoint: 60.00
22:50:16.556757 A40385000 Read-Ack DHW setpoint: 80.00
PS=1 reports 0 degrees
I cannot find the source of the 80 value... not on the knobs, not in the thermostat.

FW 3:
22:53:16.812698 T80383C00 Read-Data DHW setpoint: 60.00
22:53:16.900017 A70383C00 Unk-DataId DHW setpoint: 60.00
PS=1 reports 60 degrees

[hvxl]

Thank you for restoring normality. It annoys me when things don't make sense.

The thermostat is not trying to set the DHW setpoint. It would have to use a Write-Data message for that instead of a Read-Data message. And if it had been a Write-Data message, the gateway would have stored the value. However, the OT slave has indicated via the RBP-flags (MsgID 6) that it doesn't support write access, thus preventing the thermostat from using a Write-Data message.

There is some inconsistency in the messages from the EMS-OT converter. Via the RBP-flags message it indicates that it supports neither TdhwSet (MsgID 56) nor MaxTSet (MsgID 57), but it seems to handle MaxTSet Read-Data requests just fine.

The gateway has no way of determining the real DHW setpoint, so I believe not storing any value is the correct behavior. Picking up some random number the thermostat fabricated and presenting that as the DHW setpoint would be misleading.

The gateway uses DHW bounds of 20-80 degrees if the boiler doesn't supply any. As a default for the DHW setpoint, it picks the upper bound. That's where that mysterious 80 probably comes from. You can change it with the SW command.

[DatafoxChris]

Your answer couldn't be more clear, and I agree it is best not to show a value for DHW setpoint.

I guess I have to replace the boiler, select a brand which uses opentherm natively

[pwhooftman]

I just noticed the strangest thing: Domoticz was showing that the CWH temperature of my Calenta heater was around 55 degrees celcius, while its sunny and hot outside, and the heater isn't heating. Further investigation reveals Domoticz was reporting this temperature since 31 march / 1 april:


It's almost like it has been showing the internal 40 liter boiler temperature for days instead of the central heating temperature:


The current temperature in the devices tab of Domoticz reads 55,2 degrees:



But the current temperature on the tubing of the heater wasn't 55 degrees: the tubes are cold, the central heating hasnt been heating for hours (even days)!

I restarted the heater, the display showed the feed & return temperatures T1 and T2 on the display of the Calenta dropping from 50+ to ambient temperature. Anfter a few minutes, they flew up again to 50-60 degrees and the boiler started. But the tubes werent heating up and the CWH setpoint remained at 7 degrees, so it was heating its internal boiler. But the heater normally only reports high T1 and T2 temperatures during the one minute during the boiler heating, not permanently like the last 3 weeks.

Furthermore, i have restarted the heater again and unplugged the OTGW for a few minutes and set the boiler to ECO mode (not permanently heating the 40L boiler). T1 and T2 showing normal low values representing the CWH temperatures again. I have reneabled the 'Comfort' setting so heating of the 40L boiler (which makes the heater run for like 1 min every hour) is enabled again, and T1 and T2 temperatures remain showing the CWH temps again.

Whats going on here? T1 and T2 used to correspondent to feed- and return temperature for CWH up until 1st of april. It seems like OTWG has caused this. Is that even possible, that the heaters T1 and T2 values shown on its display are dictated externally (by the OTWG)?

[hvxl]

What probably happens is that because your house is warm enough to not need the central heating to come on, also the pump hasn't been running. Inside your heater the same flame is used to heat the built-in hot water boiler and the water in the central heating system. So whenever the water in the boiler is heated, also a little bit of water in the central heating system is heated. And because the pump never runs, that water stays pretty much where it is. The temperature sensors for the boiler water temperature and return water temperature are very close to that point and will therefor show higher than expected values.

When you restart the heater, it probably also runs the pump for a short while. That brings in cooler water from the rest of the system, which makes the temperature sensor show reasonable values again.

The OTGW is unable to influence the temperature sensor readings, but thanks a lot for the accusation

[maartenp]

I have the OTGW between my Honeywell Wireless Modulation thermostat and Bosch HRC35 Top boiler. As long as I don't have the USB connection connected there are no issues (but what's the point of having an OTWG without being able to read any values, right? ;- ) ). Whenever I connect it to my RasPi running Domoticz, the thermostat will start blinking the red light, indicating lost connection, after a minute. At this point, the heater will start heating at max. power, so you can imagine this is not really a wanted situation. I have been running latest stable firmware and I think 4 of the most recent beta builds, all showing this issue. Upgrading to 4.0b4 also does not solve it. I found out that switching from gateway to monitor mode did solve the red light (using OTmonitor on my Windows laptop) temporarily, but as soon as I connected the OTWG to the Pi, the thermostat got disconnected again

I have OTmonitor logs of the following scenario's:
(no boiler messages received during these stages, only Error 01):
Booting 4.0b3 while the thermostat red light is blinking, reconnect wireless thermostat (reverts to disconnected in a minute), upgrade to 4.0b4, boot, switch to monitor mode
(boiler messages start to appear, green light on thermostat)
switch to gateway mode
(boiler messages disappear, red light on thermostat, Error 01)
switch to monitor mode
(boiler messages start to appear, green light on thermostat)

Disconnected OTGW, connected to Pi (green light was still on)
after a while, red light again.

Connected OTMonitor and started a new log:
(no boiler messages received during these stages, OTGW seems to have switched to GW mode):
switched on "ignore multiple mid-bit transitions"
(boiler messages start to appear, green light on thermostat)

For now, "ignore multiple mid-bit transitions" seems to have solved the connection issues. I don't understand why connecting the OTGW USB connector causes error 01 in gateway mode? Apparently, when running in gateway mode while nothing is connected, everything works fine...

Two more issues:
Room setpoint seems to always stay at 10 degrees (it is currently set to 19 degrees)
Room temperature always seems to indicate 20 degrees (while the thermostat shows other values)
Are those both caused by the Honeywell thermostat not sending the right values?

Thanks for having a look!