Flow WiFi smart controller and cable kit

Local MQTT control for Daikin Altherma 2 and Altherma 3

No cloud, no Daikin account, no subscription. Works with Home Assistant and anything else that speaks MQTT.

Your Altherma already knows its flow temperature, its return temperature, how much energy it has used and how much heat it has produced. It just will not tell you without a cloud account.

The Faikin Flow wires into the P1/P2 user interface terminals on your Altherma and puts the whole system into Home Assistant over MQTT. Everything stays on your own network. There is no Daikin account, no ONECTA app, no cloud relay, and nothing stops working if Daikin changes its mind about an API.

Your existing wall controller keeps working exactly as it does now. The Faikin Flow sits on the same two-wire bus alongside it.

Choose your Altherma version

Each Altherma generation talks a slightly different dialect on the P1/P2 bus, so the module runs a different firmware build for each one. Pick the option that matches your heat pump.

• Altherma 3, split or monobloc, including the Altherma 3 H HT. This is the main build and the one most people need.
• Altherma 2, split or monobloc, including the low temperature monobloc range (EBLQ, EDLQ, EBHQ, EDHQ). Supported, on its own firmware build. The module ships ready to join your network and we switch it over to the Altherma 2 build for you once it is installed.
• Altherma 4 (testing). Not supported yet. See below.

In every case the system needs a Daikin wall controller on the P1/P2 bus, such as a BRC series controller or the EKRUCBL, because the module sits on the same bus alongside it.

Altherma 4: help us add support

The Altherma 4 has not been decoded yet. We can do it, but we need one to work on. We are offering a small number of modules at cost price, $60, to Altherma 4 owners who are happy to help get it working.

• This is a test unit, not a finished product. There is no guarantee it will work on your system, though we will make our best effort.
• By ordering this option you agree to help with remote decoding and debugging: installing the module, sending logs and captures when asked, and trying firmware builds as they come.
• Until the decode is done, expect it to report little or nothing useful in Home Assistant.
• Only a few are available. If they have gone, contact us and we will put you on the list.

What you get in Home Assistant

Control

• Leaving water temperature setpoint, with heating mode
• Domestic hot water setpoint

Water and air temperatures

• Leaving water temperature (LWT)
• Return water temperature (RWT)
• Mixed water temperature (MWT)
• Domestic hot water tank temperature
• Room temperature
• Outside temperature

Energy, split out properly

• Energy consumed by the compressor, the backup heater and in total
• Energy produced for heating, for cooling, for domestic hot water and in total
• Which means you can calculate your real COP in Home Assistant, per mode, without a separate energy meter

System state

• Heat pump mode, heating mode and main zone status
• Domestic hot water active, and tank power
• Defrost active
• Water flow rate in litres per minute
• Pump running hours
• Error flag

Hybrid systems

• Gas boiler active, gas mode, and boiler running hours split between heating and hot water

It works with what you already use

MQTT is the point. It is the most widely supported protocol in home automation, and it means the Faikin Flow is not locked to any one platform.

• Home Assistant picks it up automatically over MQTT discovery. No YAML, no template sensors. Everything above appears as proper entities with the right device classes and units.
• The Home Assistant Companion app gives you full control on iOS and Android, with widgets, notifications and location triggers. For most people this is a better daily experience than the vendor app it replaces.
• Apple Home works through the HomeKit Bridge built into Home Assistant. That runs entirely on your own network, no cloud and no subscription.
• Google Home and Alexa both have well-trodden paths out of Home Assistant, either through Home Assistant Cloud or your own setup.
• Anything else that speaks MQTT can consume it directly, including openHAB, Node-RED, ioBroker, Domoticz and Homebridge. You are not obliged to use Home Assistant at all, though it is the path we support and the one that needs no configuration.

This is exactly the arrangement that makes the Faikin Faikout so flexible, applied to your heat pump.

The rest of the house

The Faikin Flow is for your Altherma and nothing else. It does not fit a split or a ducted system, and nothing else we make fits an Altherma. These are not alternatives to each other, they are different appliances.

Most people with an Altherma also have air conditioning somewhere in the house, and that is worth knowing about before you order:

• Ducted, Sky Air and VRV are the Faikin Ninja. That one does have Matter, so if you want to scan a code straight into Apple Home without going through Home Assistant, the Ninja does it.
• Wall-mounted splits are the Faikin Faikout.

All of it speaks MQTT and all of it lands on the same dashboard, so the heat pump, the ducted system and the bedroom splits end up in one place.

Why not the alternatives?

Airzone's Aidoo needs an Airzone cloud account and the Airzone app. ESPAltherma is a do-it-yourself build onto the main system PCB rather than the thermostat bus, and it reads far more than it controls. The Faikin Flow is a commercial product that does local control, arrives pre-flashed and is supported by us.

Compatibility

Works with

• Daikin Altherma 3, split or monobloc, including the Altherma 3 H HT
• Daikin Altherma 2, split or monobloc, including the low temperature monobloc range (EBLQ, EDLQ, EBHQ, EDHQ), on its own firmware build
• Daikin Altherma 4, as a test unit only (see above)

Not this product

• Any Altherma that does not have P1 and P2 terminals on the X5M strip.

Split or monobloc, and why it matters. A split Altherma has a separate indoor hydrobox, and the X5M strip lives inside it. A monobloc has no indoor unit at all. The hydraulics and the switchbox are both in the outdoor unit, and the wall controller is the only part of the system indoors. The Faikin Flow fits either, but on a monobloc the terminals are not where the usual instructions send you.

How to check in thirty seconds. Find the terminal strip marked X5M. On a split it is inside the indoor hydrobox. On a monobloc it is inside the outdoor unit's switchbox. Look for the pair labelled P1P2 USER INTERFACE, which is the pair your wall controller already runs on. If those are there, the Faikin Flow fits.

Terminal numbering moves around between Altherma generations, so go by the P1P2 USER INTERFACE label rather than by the numbers printed beside it.

Note that this is not the same place as on a Daikin split or ducted air conditioner, where P1/P2 sits on the REMOTE CNTRL block next to F1/F2 and T1/T2. On an Altherma it is lower down the X5M strip.

Send us your model number and a photo of the X5M strip and we will confirm it for you before you order.

Installation

1. Isolate power to the whole system, indoor and outdoor.
2. Open whichever unit holds the X5M strip. On a split Altherma that is the indoor hydrobox. On a monobloc it is the switchbox inside the outdoor unit.
3. Find the pair on X5M labelled P1P2 USER INTERFACE. These are the terminals your wall controller is already wired to.
4. Connect the two module wires alongside the existing pair. The connection is non-polar, so either wire can go to either terminal. Wire is 24 to 12 AWG, 0.6 to 2.4 mm.
5. Restore power. There is no separate power supply to run.

On a monobloc, think about where the module ends up. The switchbox is outdoors and this enclosure is not weather rated, so the Faikin Flow needs somewhere dry and within WiFi range. The same P1/P2 pair also lands at your wall controller indoors. That is the same two wires and the same bus, and it is often the easier and drier place to connect. Ask us if you are not sure which suits your install.

The P1/P2 bus allows one Main and two Sub devices. Your wall controller is the Main and stays exactly as it is. The Faikin Flow takes one Sub slot, and a Daikin LAN adapter for the Onecta app can take the other, so the two run side by side. If both Sub slots are already in use, for example by a second controller, one of them has to come off first.

This is work inside a live appliance. If you are not comfortable opening the unit and working on a terminal strip, get your installer to do this part. It takes them five minutes.

Setting it up

No app, and nothing to install. The setup is a web page served by the module itself, so any phone or laptop with a browser will do.

1. Power it up. The module brings up its own WiFi network, named FaikinAC- and four characters.
2. Scan the QR code on the label with your phone camera and it joins that network for you. You can pick it out of your WiFi list by hand instead if you would rather.
3. The setup page opens by itself. Choose your home WiFi from the list and enter the password.
4. Enter your MQTT broker address, the port (1883 unless you have changed it), and the username and password if your broker uses them. You can do this now, or leave it and come back to it later once the module is on your network. It is the same page either way.
5. Press Save and Reboot. It tells you the IP address it has been given, then restarts.
6. Browse to that address whenever you want status, settings or a firmware update.

The status page tells you separately whether MQTT is connected and whether the module is talking to the heat pump, which makes it straightforward to tell a wiring problem from a network one.

Specifications

• Connection: two-wire P1/P2, at the X5M terminals inside the hydrobox on a split or the outdoor switchbox on a monobloc
• Power: from the P1/P2 bus. No separate supply, no batteries
• Wi-Fi: 802.11 b/g/n, 2.4 GHz
• Reporting: MQTT, with Home Assistant auto-discovery
• Configuration: built-in web page, no app required
• Firmware: ships flashed and tested, updates over the air
• Cable: two-wire ferrule-blade lead included, sized for the X5M screw terminals
• Enclosure: plastic, for indoor use. Not weather rated

What this does not do

• No direct Matter pairing. An Altherma exposes roughly sixty entities and that does not map onto a Matter thermostat, so there is no code to scan straight into Apple Home the way there is on the Ninja. You reach Apple Home, Google Home and Alexa through Home Assistant instead, which is how the Faikout has always worked.
• No vendor app of our own, by design. The built-in web page is for setup and diagnostics. Day to day you use the Home Assistant Companion app or whatever dashboard you already have, which is a better app than we would ever write.
• No field settings. Installer-level configuration stays on the wall controller.
• Not a replacement wall controller. It runs alongside yours, not instead of it.
• Entities you do not have will not appear, or will read as unavailable. A system with no domestic hot water tank will not report tank temperature.

FAQ

Do I need Home Assistant?

It is what we recommend and support, and it needs no configuration because the module is picked up automatically over MQTT discovery. But this is a plain MQTT device, so openHAB, Node-RED, ioBroker, Domoticz and Homebridge can all read it directly if that is your setup.

Is there an app?

The Home Assistant Companion app, on iOS and Android, with widgets, notifications and location triggers. We do not ship an app of our own and we are not going to, because the Companion app is better than anything we would build and it puts your heat pump on the same dashboard as everything else in the house. Setup itself needs no app at all, just a browser.

Does it work with Apple Home?

Yes, through the HomeKit Bridge built into Home Assistant. That runs locally on your own network, with no cloud and no subscription. What it does not have is the scan-a-code Matter pairing on the Ninja, because sixty-odd heat pump entities do not fit a Matter thermostat.

Google Home, Alexa, SmartThings?

All reachable out of Home Assistant. Google Home and Alexa are the most direct, either through Home Assistant Cloud or your own setup.

I have a monobloc. Does that change anything?

Only where you connect it. A monobloc runs the same P1/P2 user interface bus as a split, so the module works the same way and reports the same things. The difference is that there is no indoor hydrobox, so the X5M strip is in the outdoor unit's switchbox, and the module itself needs to sit somewhere dry. Connecting at the wall controller end indoors is usually simpler.

Will it fight with my wall controller?

No. The module joins the bus as a Sub device. Your wall controller remains the Main and keeps full function. The bus has room for two Sub devices, so a Daikin LAN adapter can stay fitted alongside it. Only if both Sub slots are already taken does something have to come off.

Can I still use the Daikin app?

If you have a Daikin LAN adapter fitted, yes, both can coexist. The LAN adapter takes one Sub slot on the bus and the Faikin Flow takes the other. The Faikin Flow does not need it and does not talk to it.

Does it need internet?

Only to fetch firmware updates. Control is entirely local. Pull the internet and it keeps working.

Can I flash it myself?

No. It ships pre-flashed with the build for the Altherma version you chose, and updates over the air. Do not attempt to reflash it.

What if it does not work on my system?

Send it back. Our no-risk returns cover you, and we would rather sort it out or take it back than have you stuck with something that does not suit your heat pump. The Altherma 4 test units are the exception: they are sold at cost on a best-effort basis.

Which Altherma do I have?

The model number is on the data plate. On a split that is on the indoor hydrobox, on a monobloc it is on the outdoor unit. Send us a photo of the plate and of the X5M terminal strip and we will tell you, and which option to order.