Scheduled DHW Eco/Comfort mode: Remeha Calenta+Evhome+OT GW

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Scheduled DHW Eco/Comfort mode: Remeha Calenta+Evhome+OT GW

Postby jgeo » Mon Jun 07, 2021 11:26 am

I try to achieve a time-scheduled DHW mode switching between Eco- and Comfort mode, on a Remeha Calenta Ace 40c in combination with an Evhome (zoned thermostat) and possibly by using OpenTherm Gateway (OTGW https://www.nodo-shop.nl/en/opentherm-g ... teway.html) in combination with Home Assistant.

In Eco-mode, the Remeha heater only heats when hot water is requested, in Comfort mode, the heat-exchanger keeps being pre-heated to 45 degrees, and so the burner switches briefly on every 25 minutes. I'd like it to pre-heat in the morning and evening, but in Eco mode during the rest of the day.

The manual of the Remeha Calenta Ace 40c says I can set it to scheduled operation, but when I navigate to the clock-schedule it says "SEE RU". Which means that I should use the Remeha eTwist thermostat to achieve this, but I don't have one since I control my heating system with a Honeywell Evohome, since I have zoned floor-heating.

How can I probram this DHW mode?
1) Should it be possible to program it on the Remeha Calenta Ace 40c itself? If I would temporarily borrow an eTwist, can I program the heater for scheduled DHW mode switching, then replace the eTwist by the Evohome again, and have it running forever with the same schedule?
2) Does the eTwist normally execute the schedule, and would the Remeha Calenta Ace 40c just act as a slave? So is it only possible if an external device operates the DWH mode?
3) Can I set the mode through the OpenTherm interface?

In OpenTherm monitor (https://otgw.tclcode.com/otmonitor.html) there is an option (Configuration > Heater) for Comfort Setting (Comfort mode, Economy mode, Thermostat controlled). That seems to correspond to the setting on the boiler of
DP200=0 "klokprogramma" = scheduled (but setting the schedule does not work: SEE RU)
DP200=1 "handmatig" = manual (comfort mode)
DP200=2 "vorstbeveiliging" = freezing prevention (eco mode)
But unfortunately, that doesn't do anything with the behaviour of the system. I see a message in the Opentherm logging: HW=0 or HW=1 or HW=A, there is even a confirmation, but the Remeha keeps doing what it did according the the manual setting of the configuration menu on the boiler itself.

Remeha support is totally inadequate, and refer to my equipment installer, who tells me I shouldn't do those difficult things. So that's a dead end.

Opentherm Monitor: Economy Mode
10:49:16.355276 T80000200 Read-Data Status (MsgID=0): 00000010 00000000
- DHW enable: enabled (1)
10:49:16.535341 R00000000 Read-Data Status (MsgID=0): 00000000 00000000
- DHW enable: disabled (0)
10:49:16.658800 BC0000000 Read-Ack Status (MsgID=0): 00000000 00000000
- DHW mode: not active (0)
10:49:16.781653 A40000200 Read-Ack Status (MsgID=0): 00000010 00000000
- DHW mode: not active (0)

Opentherm Monitor: Comfort Mode
10:50:45.864392 T80000200 Read-Data Status (MsgID=0): 00000010 00000000
- DHW enable: enabled (1)
10:50:46.021366 B40000200 Read-Ack Status (MsgID=0): 00000010 00000000
- DHW mode: not active (0)

Opentherm Monitor: Thermostat controlled
10:51:40.547413 T80000200 Read-Data Status (MsgID=0): 00000010 00000000
- DHW enable: enabled (1)
10:51:40.719299 B40000200 Read-Ack Status (MsgID=0): 00000010 00000000
- DHW mode: not active (0)

The only difference I see here is between switching the OpenTherm monitor mode to economy mode and the other modes:
Then it sends after the T80000200 Read-Data another R00000000 Read-Data.

According to http://otgw.tclcode.com/firmware.html, it should be possible to use the HW=... command to set the behaviour, but either it's not correctly passed to the boiler, or it's ignored. According to https://www.domoticaforum.eu/viewtopic.php?f=75&t=11896 I need to set the P4 but, but I have no clue how to do that.
jgeo
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