Flexit Nordic (BACnet) - Roadmap & ideas

Configuration
42

I have a Flexit wh4 and it would be fantastic if I just could change the water mode (Eco, Comfort, Boost) and temperature of the heat pump via HA according to: Add more features in Flexit bacnet integration - Thanks for great work on this so far!

1 Like
43

My flexit has a, what old integration called “Boost Temporary” mode GitHub - sindrebroch/ha-flexit
which allowed me to activate a 20min boost mode. Boost mode was also visible on the hvac controllers in our apartment, with timer and option to cancel it from controller.

Now the “boost” mode in the flexit_nordic actually just activates the “high” preset, which never goes back to home.
I will try to fix this with additional automation, but it would be cool if it could support “Boost Temporary” mode natively.

(linked old library for reference, maybe its code contains something useful regarding temp boost)

2 Likes
44

Hi! I am a first time user here taking the opportunity to thank everyone for their work and putting myself in the kind reqest line for including the Flexit Econordic WH4 compatibility in this HA Integration. Warm water temperature, mode switch and compressor status would be brilliant!

I would be willing to co finance any work leading up to this integration, let me know if that would help

Are there any Flexit officialls here or is all crowd developed? It was a major usp for Flexit having a HA integration. Hope Flexit supports!

(I will likley not check any comments here at speed but will log in and have a look once in a while)

@mwahss

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Hey @Aarflot , are you able to execute some python code on your machine to dump the properties from your Flexit unit?

I’ve prepared this script GitHub - piotrbulinski/bacnet_dump: The tool to dump BACnet device objects which allows for a discovery of what properties can be returned and controlled on the unit. Without having access myself to the unit, this is really the only way for me to learn about the properties which are there and aren’t on mine.

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Hi @piotrbulinski , I have a dump from my Flexit Econordic WH4 for download here: iCloud Drive - Apple iCloud

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@mwahss this is great, thank you.

For the water mode I see quite clear the “Domestic hot water mode” property with the options you’ve mentioned, so that one should be easy to do.

But for the water temperature there are 3 properties, so need to figure out which one is the one you are looking for to adjust:

  • Heat pump setpoint flow temperature: 45*C
  • Setpoint high flow temp.for heat pump: 65*C
  • Setpoint low flow temp.for heat pump: 45*C

Does any of those properties look like the one you want to control?

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No, I dont think so. Is there something that looks like “room temperature”? Images in the attached pdf. In the app I can set room temperature under the heating tab (uppvärmning) and water mode under the water tab (vatten - available modes are eco comfort and boost. Boost is temporary)

Only water mode would be a very valuable addition!

There is also an electric heater that would be nice to be able to control (on/off).

https://acrobat.adobe.com/id/urn:aaid:sc:US:0b07b45d-a9db-442d-b9f3-074c4a4c5bd2

@piotrbulinski

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There is also a bug for us econordic users in the ventilation part. As you see in the screenshot the temperature is 0 degrees (but it is 21.5 in my house now). It is always zero so probably some sensor missing in my product. Would be nice if this value could fall back to the extract air temperature.

IMG_4904
IMG_49041170×2532 150 KB

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Hi again @piotrbulinski!

After analyzing the BACnet dump from my Flexit WH4, I have identified relevant objects and additional useful values. However, the most important improvements in terms of control functionality (ranked by priority) would be:

  1. Ability to control domestic hot water mode
  2. Ability to control domestic hot water temperature
  3. Ability to control room temperature setpoint
  4. Ability to set the electric reheater activation threshold

SYSTEM STATUS

Current operating mode of the heat pump (display only):
[“multiStateValue”, 40] “Plant operating mode for heat pump” [“Off”, “Vent.heating from tank”, “Load tank”, “Load tank & vent.heating”, “Space heating from tank”, “Space heat.& vent.heat.from tank”, “Load tank & space heat.”, “Load tank & space heat.& vent.”, “HP not available”, “Swi-off delay flow through heat.”, “Legionella prev.vent.heat.”, “Legionella prev.space heat.”, “Space heat.with HP”, “Space heat.& vent.with HP”, “Load tank & space heat.with HP”, “Load tank & vent.& space with HP”, “Legionella prev.tank”]

HEATING (SPACE HEATING)

Room temperature (setpoint - control)
[“analogValue”, 1918] “Room temp.setpoint for heating circuit”

Flow temperature (setpoint - display only)
[“analogValue”, 258] “Flow temp.setpoint for heating circuit”

Flow temperature (actual - display only)
[“analogValue”, 325] “Flow temperature output heating circuit”

Return temperature (actual - display only)
[“analogValue”, 326] “Return temp.output heating circuit”

Heating circuit pump speed (display only)
[“analogOutput”, 30] “Heating circuit pump speed” (percentage)

DOMESTIC HOT WATER (DHW)

Domestic hot water mode (control) - can be exposed as a water_heater entity with operation modes:
[“multiStateValue”, 423] “Domestic hot water state” [“Comfort”, “Economy”, “Boost”]
[“multiStateValue”, 424] “Domestic hot water temporary boost” [“Ready”, “Start”, “Stop”]
[“multiStateValue”, 425] “Domestic hot water forced charge” [“Ready”, “Start”]

Domestic hot water temperature (control - target temperature for water_heater entity):
[“analogValue”, 253] “Setpoint domestic hot water temperature”
[“analogValue”, 2127] “Setpoint domestic hot water temp.f.eco.”

Tank temperature sensors (display only) - these measure actual water temperatures. The top sensor can be used for current_temperature in the water_heater entity.
[“analogInput”, 70] “Temperature, hot water tank top”
[“analogInput”, 69] “Temperature, hot water tank middle”
[“analogInput”, 58] “Temperature, hot water tank bottom”

HEAT PUMP STATUS

Heat pump status (display only):
[“multiStateInput”, 1] “Heat pump state” [“Standby”, “Air purge process”, “Startup process”, “Normal operation”, “Stop process”, “Defrost operation”, “Standby when error”, “Manual operation”, “Forced fan operation”, “Forced pump operation”]

Heat pump thermal power output (display only - kW):
[“analogOutput”, 17] “Heat pump thermic power output”

Heat pump compressor speed (display only - Hz):
[“analogInput”, 56] “Heat pump compressor speed feedback”

ELECTRIC REHEATER

Electric reheater activation threshold (control):
[“analogValue”, 276] “Outs.air temp.limit elec.reh.heat.circ.” (°C)

Electric reheater heating request (display only - percentage):
[“analogValue”, 196] “Heating coil heating request”

Electric reheater power usage (display only - kW):
[“analogValue”, 194] “Heating coil electric power”

ROOM SENSORS (OPTIONAL)

These are optional sensors (VMSH 1-3 are humidity sensors, and RF is a CO₂ sensor).
Mabye they can be hidden if their values are 0.0°C.
I personally have VMSH 1+2 in two bathrooms, but no VMSH 3 or RF.

[“analogInput”, 83] “Room temperature VMSH 1” (°C)
[“analogInput”, 84] “Room air humidity VMSH 1” (%)
[“analogInput”, 86] “Room temperature VMSH 2” (°C)
[“analogInput”, 87] “Room air humidity VMSH 2” (%)
[“analogInput”, 89] “Room temperature VMSH 3” (°C)
[“analogInput”, 90] “Room air humidity VMSH 3” (%)
[“analogInput”, 92] “Air quality, max value RF” (ppm CO₂)

Fix for the Room Temperature Display Issue

One additional improvement that would greatly enhance the integration is implementing a fallback for the room temperature in the ventilation system. If [“analogInput”, 75] ‘Room temperature’ reports 0.0°C, it should automatically use [“analogInput”, 59] ‘Extract air temperature’ instead. This would ensure that room temperature is always displayed correctly, even for systems without a dedicated room sensor.

I truly appreciate all the hard work that has gone into developing this integration. It has been incredibly useful, and I’m grateful for the effort put in by the community. I hope these suggestions can help make it even better, and I’m excited to see how it evolves. Thanks again for this fantastic integration!

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@mwahss this is great, thank you. On my end I can share that I talked with Flexit Sweden last week and they agreed to send me their documentation on different units, which sensors are optional and how to detect them, etc. They are pretty busy there, so this might take a few days/weeks, but once I get the documentation, I’ll start working on the improvements to the flexit_bacnet library and then naturally add that to the Home Assistant integration.

1 Like
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Thank you for the reply and engagement @mwahss and @piotrbulinski! This all seems very promising! On my end I only have the W4, so for me it is basically the DOMESTIC HOT WATER (DHW) that is of any functionality for me, but would be so great to include in HA.

I am set to have a meeting with a sales representative of Flexit Sweden sometime soon so will make sure to push this as well and see if I can give the tech support in Norway as well so to help them help you in any way.

Let me please know if you have a contribution site @piotrbulinski so that can contribute for your work.

(Will probably again not have a look here anytime soon, but looking forward to seeing the development)

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@mwahss I have talked to Flexit tech support and mentioned your documentation request @piotrbulinski. They said all documentation is avaliable here: Flexit GO under “Documentation” and while there is a Modbus description for the WH4, there is not a bacnet documentation.

Other than that I did not get further as I do not know what other documentation you have necessary @piotrbulinski. Let me know what information I can be of assistans in requesting and I shall do so!

@mwahss, what is interesting is this line from your Bacnet dump:
"Domestic hot water temperature (control - target temperature for water_heater entity):
[“analogValue”, 253] “Setpoint domestic hot water temperature”
[“analogValue”, 2127] “Setpoint domestic hot water temp.f.eco.”

This is actually the most important feature because it could allow me to force a very low hot water temperature depending on power tariff and solar production and thus enable anyone to “place” warm water heating in time when suitable. However I did not find this feature in the official documentation from Flexit on the webpage above. I sincerely hope this temperature is adjutable, otherwise I will make sure to ask for a change in this feature from Flexit.

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The erhv card looks nice! A very minor point is the color scheme during a heatwave is not correct :sweat_smile:

image
image1004×442 34.5 KB

Below my configuration, I think I translated the fields correcty, if not please let me know.

type: custom:erhv-card
title: Flexit
entity: climate.hvacfnct21y_a
climate_entity: climate.hvacfnct21y_a
name: Flexit
supply_temperature: sensor.hvacfnct21y_a_supply_air_temperature
return_temperature: sensor.hvacfnct21y_a_extract_air_temperature
intake_temperature: sensor.hvacfnct21y_a_outside_air_temperature
exhaust_temperature: sensor.hvacfnct21y_a_exhaust_air_temperature
intake_fan_speed_rpm: sensor.hvacfnct21y_a_supply_air_fan
exhaust_fan_speed_rpm: sensor.hvacfnct21y_a_exhaust_air_fan
exhaust_fan_speed_percentage: sensor.hvacfnct21y_a_exhaust_air_fan_control_signal
filter_elapsed_time: sensor.hvacfnct21y_a_air_filter_operating_time
show_empty: true
intake_fan_speed_percentage: sensor.hvacfnct21y_a_supply_air_fan_control_signal
filter_warning: binary_sensor.hvacfnct21y_a_air_filter_polluted
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Hi all regarding Econordic water control functionality in bacnet integration,

I have talked to my Flexit sales rep today and asked him to fastrack both Flexit Go feature updates (scheduling of warmwater mode and adding “off/away” and to update the documentation as you asked for @piotrbulinski.

I wish there is something more I can do, let me know if that is the case. In the mean time I have attempted a modbus integration, but the communication protocols is really giving med a hard time and no result as of yet.

1 Like
56

Are you still working on the Home assistant integration? I thought you did an amazing job and would love to support fiancially if possible.

I’m trying to get the WH4 Heatpump to only heatup while electricity costs are low, and the best way i’ve found to do so is through adjusting the set outside temperature at which the heatpump should start heating up and down.

It would be great if this was avaiable through home assistant so it could be automated and not be a manual task i do every day haha <3

57

Hi Piotr. I have a WH4 and it seems I cannot heat enough my 200m2 house. One reason I see is that circulation pump is almost all the time on 30%. If I change delta from 5k to higher number - doesnt help because it will not increase speed from 30%. If I set lower number - it will increase to 40%.

Is there any chance to control this water circulation pump?

Thanks,
Pali

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@Fterka If you want faster circulation you need to set a lower delta, not higher. I had the same problem. I now have delta 3 in a 170m2 house. Works perfectly for my house. You might have to tune other parameters as well. Contact your installer or Flexit support.

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I know increasing delta - lowering pump speed. Currently I have delta 2 and pump runs on 64% and temp is not increasing :frowning: 21,1 goes in and return 19,1 - same last two days… The best for me would be to set delta on 7 and control the pump on 80%. Isnt there any feature how to increase pump other way than by delta? thanks, pali

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EcoNordic WH4 – BACnet behavior clarification & implementation notes

Hi Piotr,

Below is a technical clarification regarding EcoNordic WH4, based on extensive real-world testing on a physical WH4 unit using Home Assistant + Node-RED, BACnet object dumps, and verification against actual behavior in the Flexit app. All behavior described here has been practically verified.

The goal is to explain why some entities don’t work on WH4 today and to provide concrete BACnet details that could be used if EcoNordic support is ever considered.

Nordic vs EcoNordic WH4 – why model-specific handling is required

EcoNordic WH4 differs fundamentally from Nordic units:

  • Nordic: FTX only
  • EcoNordic WH4: FTX + heat pump + space heating + domestic hot water (DHW)

Several functions use different BACnet objects and control logic, especially DHW and timed ventilation functions. Supporting both models properly likely requires model selection or a WH4-specific variant.

Domestic Hot Water (DHW) – EcoNordic only

DHW operating mode

  • Object: multiStateValue 39 (RW)

  • Values:

    • 1 = Comfort
    • 2 = Eco
    • 3 = Boost

This is also the most reliable way to read whether DHW boost mode is active (39 == 3).

DHW temporary boost (timed)

  • Object: multiStateValue 424 (W)

  • Values:

    • 2 = Start timed boost
    • 3 = Stop / cancel boost

No separate “time remaining” object for DHW boost has been identified on WH4.

DHW temperature setpoints

  • Comfort setpoint: analogValue 253 (RW, °C)
  • Eco setpoint: analogValue 2127 (RW, °C)

DHW tank temperatures (read-only)

  • Bottom: analogInput 58 (°C)
  • Middle: analogInput 69 (°C)
  • Top: analogInput 70 (°C)

DHW electric heater status

  • Object: analogValue 264 (read-only indicator)
  • Values: 0 or 100 (%)

Space heating (EcoNordic only)

  • Room temperature setpoint for space heating:
    analogValue 1918 (RW, °C)

This is separate from ventilation temperature control.

Plant operating mode for heat pump (read-only)

  • Object: multiStateValue 40

  • States:

    1. Off
    2. Ventilation heating from tank
    3. Load tank
    4. Load tank & ventilation heating
    5. Space heating from tank
    6. Space heating & ventilation heating from tank
    7. Load tank & space heating
    8. Load tank & space heating & ventilation
    9. Heat pump not available
    10. Switch-off delay, flow-through heating
    11. Legionella prevention, ventilation heating
    12. Legionella prevention, space heating
    13. Space heating with heat pump
    14. Space heating & ventilation with heat pump
    15. Load tank & space heating with heat pump
    16. Load tank & ventilation & space heating with heat pump
    17. Legionella prevention, tank

Heat pump internal state (read-only)

  • Object: multiStateInput 1

  • States:

    1. Standby
    2. Air purge process
    3. Startup process
    4. Normal operation
    5. Stop process
    6. Defrost operation
    7. Standby when error
    8. Manual operation
    9. Forced fan operation
    10. Forced pump operation

States 11–15 exist in the object but appear unused on WH4.

Indoor climate – wireless room sensor humidity

  • analogInput 2093 – RH sensor 1
  • analogInput 2094 – RH sensor 2
  • analogInput 2095 – RH sensor 3
    (only present if the corresponding sensor is installed)

Ventilation – timed functions on EcoNordic WH4

On WH4, High and Fireplace are trigger-based timed functions; duration is configured in the Flexit app.

High (timed)

  • Trigger: binaryValue 355
  • Write value: 2 = Toggle (start/stop)
  • Time remaining: analogValue 2029 (read-only, minutes)

Fireplace (timed)

  • Trigger: binaryValue 358
  • Write value: 2 = Toggle (start/stop)
  • Time remaining: analogValue 2036 (read-only, minutes)

Cooker hood

  • Trigger: binaryValue 2

  • Write (ENUM, priority 13 required):

    • 1 = Active
    • 0 = Inactive

Cooker hood is pure on/off; no duration object is exposed via BACnet.

Detecting whether High / Fireplace are active

Do not rely on 2029 > 0 or 2036 > 0 as a boolean indicator on WH4, as these values show the configured default duration even when the function is not running.

The reliable indicator is:

  • Ventilation mode status: multiStateValue 361 (read-only)

    • 4 = High
    • 6 = Fireplace
    • 5 = Cooker hood

The timer objects (2029 / 2036) are useful only as countdowns while the function is active (value decreasing over time).

Per-mode fan flow setpoints (these exist and are RW on WH4)

The following fan flow setpoints are valid writable objects on EcoNordic WH4 (unit: mÂł/h). All are analogValue and RW:

Mode Supply Extract
Away AV18 AV12
Home AV19 AV13
High AV20 AV14
Fireplace AV16 AV11
Cooker hood AV15 AV10

Note: In the BACnet dump, the description strings for Fireplace supply and Cooker hood supply were swapped. Verification against the Flexit app confirms the mapping above.

HA entities that do not work on EcoNordic WH4 (and why)

  • FTX Room temperature always reads 0.0°C on WH4. The unit does not expose a true indoor temperature sensor. A practical alternative is using extract air temperature as a proxy.

  • Runtime/status entities for timed functions does not map 1:1, since WH4 uses trigger objects plus separate timer values (2029 / 2036) and ventilation mode status (361).

  • On EcoNordic WH4, all ventilation modes expose explicit writable fan flow setpoints via BACnet, but these are not currently usable with the Nordic-based Home Assistant integration.

Summary

All information above is based on a real EcoNordic WH4 BACnet dump, extensive Node-RED testing in Home Assistant, and verification against the Flexit app. I hope this clarifies current WH4 limitations and provides concrete input if EcoNordic support is ever considered.

Best regards

1 Like
61

Well, this is impressive! Let me figure out how to get rid of my wife and children for a day in the next two weeks, and I’ll try to add that to the library :wink:

1 Like