Lambda heat pump smart home integration, free and open source
Lambda heat pumps (EU-L) over local Modbus: temperatures, COP, circuits, optional commands.
Published by LM1LC3N7
- Devices
- Version 0.1.2
- Requires Gladys >=5.1.0
- ★ 0
Shows a Lambda heat pump (EU-L series) in Gladys through the Modbus TCP interface of its controller, on your local network, without any cloud.
This integration has never been tested with a real device: it follows the manufacturer's Modbus manual ("Modbus-Protokoll 1.0") and the Home Assistant integration lambda_heat_pumps. Feedback from an owner is welcome. Not affiliated with Lambda Wärmepumpen.
Before you start
- The controller answers Modbus TCP on port 502, unit id 1, as delivered. Give it a fixed IP address in your router.
- Modbus has no password: anyone on the network can read and write the heat pump. Keep it on a trusted network, never reachable from the Internet.
- The controller closes a connection idle for one minute; Gladys keeps one connection and closes it after 45 s without a request. Another Modbus client (Home Assistant, an energy manager) may share the controller: each one writes its own requests.
Configuration
| Field | Meaning |
|---|---|
| IP address of the controller | IPv4 address or host name, :port if not 502 |
| Modbus unit id | 1 unless your installer changed it |
| Heat pumps, hot water tanks, buffer tanks, heating circuits | how many of each module, as the display shows them (1 to 5, 0 to 5, 0 to 5, 0 to 12) |
| Allow the commands | off by default (see below) |
| Hot water ceiling | 65 °C by default, 40 to 65 °C, never more than 65 °C |
| Refresh interval | 30 s by default, 10 s to 10 min |
Save, then add the devices from the Discovery tab. "Test the connection" shows the state of the last read; it reads again only once the interval has passed since the last read.
Devices
One device per module, named as on the display:
- System: outdoor temperature (1 h average and the one of the heating curve), state and error number, energy manager state, power drawn by the heat pumps (W) and its target.
- Heat pump n: flow, return and source temperatures, compressor rating (%), heating output (kW), inverter power drawn (W), COP, error state and number, state, operating state, electric heater relay.
- Hot water tank n: top, bottom and circulation temperatures, circulation pump, state, error number, hot water setpoint.
- Buffer tank n: top and bottom temperatures, state, error number, maximum temperature.
- Heating circuit n: flow, return and room temperatures, calculated flow setpoint, heating curve offset, room setpoints (heating, cooling), state, error number, operating mode request.
A feature appears once its register gave a value: 0x8000 ("not available"), -3000 ("sensor not connected") and values out of a plausible range are never published. Registers that only some firmware versions serve (E-heater relay, energy manager, calculated flow setpoint, buffer maximum) are left out when the controller refuses them. The energy statistics of the heat pumps are not read (their word order changed with the firmware, and they can be reset): no energy index.
Commands
Stopping a heating circuit (always allowed)
Choosing Off in the mode of a heating circuit stops it, whatever the
"Allow the commands" option. The mode is a Modbus request the controller
forgets unless it is written again, so Gladys holds the stop: it is written
at once (before the reads waiting, a read silent for one second is cut),
read back, kept in /data and written again every 20 s, also after a
restart of the integration, before Gladys or its configuration are reached.
The stop is not refused for the option, a read or command in progress, a
configuration Gladys cannot read (the controller kept in /data is used) or
/data that cannot be written (the status says the stop will not survive a
restart). A stop that the controller does not acknowledge, or reads back
otherwise, is answered "not confirmed" and still written every 20 s. It waits
only when no address is known at all (no configuration and nothing in
/data): then it is written as soon as the address is.
Holding the stop would override any other actor that asks for a mode through Modbus, so Gladys reads the mode before each new write. The stop never ends by time; the status says since when it is held (in the time zone of Gladys). It ends, and the controller goes back to its own setting once the last request lapses (the heating may then start again), only when:
- two reads in a row (2 s apart) show another documented mode request (2 to 6: automatic, automatic heating or cooling, frost protection, summer) that is neither the stop nor the request read before the stop. This is how to end it from another Modbus client, and most likely from the panel (to be confirmed, see below). Gladys writes nothing between the two reads. Anything else is written over: a request that only lapsed (-1), the request read before the stop (the stop not applied yet: after three such reads the status says the controller does not apply it), an unknown code, "manual" or "screed" (1, 7), a sentinel, a failed read. When the request before the stop is not known (the stop chosen during an outage, without a recent read), the first documented request (-1 to 7) read while the stop was never read applied stands for it: it is written over, never taken for a change. A stop read applied with no request before known is ended by any request 2 to 6 read twice in a row;
- the heating circuit is removed from the configuration (fewer heating circuits), its device is deleted, or the address is cleared or changed;
- another mode or No request is chosen in Gladys: both start the heating again, so both need "Allow the commands".
After a restart of the integration the stop kept in /data is written once
without a read first: a mode chosen at the panel or by another client while
the integration was stopped is overwritten, so it is lost. Gladys then reads
the mode before each write (every 20 s): only a choice made after that first
write, and other than the request before the stop, ends the stop as above
(two reads in a row).
A command sent before the stop and still waiting is dropped.
Setpoints at their minimum (always allowed)
A room setpoint of 15 °C or a hot water setpoint of 25 °C is written whatever the option. When it is not read back, the next three reads (within 15 minutes) write it again, as long as they still show the value it replaced: a setpoint changed since (at the panel or by a newer command) is left alone.
Other commands (option "Allow the commands")
- Mode of a heating circuit: automatic, automatic heating, automatic cooling, frost protection, summer, or "No request". The mode chosen is held and written again every 20 s while the option is on, for 24 hours at most (then the controller takes over again); turning the option off stops it, and so does a restart (only a stop is kept). "Manual" and "Screed program" are shown by the controller but never set.
- Room setpoint (heating): 15 to 40 °C, tenths of a degree.
- Hot water setpoint: whole degrees, 25 °C up to the ceiling of the configuration (65 °C by default, never above 65 °C). The ceiling is checked when the command arrives and again right before it is sent.
Each command reads the current value first (nothing is sent when it cannot be read), one command at a time per module. It succeeds only when the value read back after the write is the one asked; otherwise Gladys logs "not applied yet", "sent, without confirmation" or "nothing sent". The answer to Gladys comes within 3.4 s; a command still waiting behind others then is accepted and its outcome logged. It is sent within 10 s of the click, or not at all.
Not done (yet)
- Never tested with a real controller: the register map, the COP scale and the delay before a mode request lapses need confirming on a real one.
- Whether a mode chosen at the panel of the controller shows in the Modbus request (register 5x06) is still to be checked: that is what lets the panel end a stop. Until then, the proven ways are Gladys (another mode or "No request", commands allowed) and another Modbus client.
- No solar module, no energy index, no PV surplus nor buffer requests (they must be written regularly and drive the heat pump directly).
Configuration settings
These are the settings Lambda heat pump asks for in its configuration screen in Gladys.
| Setting | Type | Required | Description |
|---|---|---|---|
| Your Lambda heat pump | section | No | Shows your Lambda heat pump (EU-L series) in Gladys through the Modbus TCP interface of its controller, without any cloud: temperatures, COP, states, heating circuits, hot water, buffer tank. The heating circuit can be stopped at any time; the other modes and the setpoints only once "Allow the commands" is on. Enter the IP address of the controller (give it a fixed address in your router), the number of each module as on its display, save, then add the devices from the Discovery tab. Modbus has no password: keep the heat pump on a trusted network. Never tested with a real device. Not affiliated with Lambda Wärmepumpen. |
| IP address of the controller | string | Yes | An IPv4 address or a host name (Modbus port 502 unless you add one, for example 192.168.1.40:5020). |
| Modbus unit id | number | No | 1 unless your installer changed it. |
| Heat pumps | number | No | How many heat pump modules the controller shows (1 to 5). |
| Hot water tanks | number | No | How many hot water tanks (0 to 5). |
| Buffer tanks | number | No | How many buffer tanks (0 to 5). |
| Heating circuits | number | No | How many heating circuits (0 to 12). |
| Allow the commands | boolean | No | Off by default. On: Gladys may change the mode of a heating circuit, its room setpoint and the hot water setpoint (up to the ceiling below). Off: these commands are refused. Stopping a heating circuit and a setpoint at its minimum (room 15 °C, hot water 25 °C) are always allowed. A stop is held (written again every 20 s, never ended by time) until a mode other than the one requested before the stop is asked by another Modbus client or at the panel, or another mode or "No request" is chosen in Gladys with this option on. |
| Hot water ceiling (°C) | number | No | Scalding risk: Gladys never sets the hot water above this temperature. 65 °C by default, from 40 to 65 °C (never more than 65 °C, whatever is typed). |
| Refresh interval (s) | number | No | How often the controller is read, in seconds. |
| Language of the feature names | select | No | Used for the names of the devices and features added from now on, for the state texts and for the command errors. |
How to install Lambda heat pump in Gladys
- In Gladys, open Integrations: Lambda heat pump appears in the catalog, next to the native integrations, with a community badge.
- Click Install. Gladys pulls the Docker image (
ghcr.io/lm1lc3n7/gladys-lambda-heat-pump:0.1.2), starts it in a sandbox isolated from the core, and generates the integration's interface (devices, discovery and configuration). - Open the Configuration screen of the integration, fill in the settings, and save.
- You can also install it directly from its repository URL: https://github.com/LM1LC3N7/gladys-lambda-heat-pump.
Lambda heat pump requires Gladys >=5.1.0. The catalog inside Gladys refreshes every hour, so a new version becomes available at most one hour after its release.
Not running Gladys yet? It is free and open source: follow the installation guide to get started.
About external integrations
Lambda heat pump is an external integration: a community integration packaged as a Docker container and published on GitHub, that Gladys installs in one click and runs in a sandbox isolated from its core. It is published and maintained by LM1LC3N7, not by the Gladys core team.
- Browse all integrations, native and community
- Build and publish your own external integration
- Source code on GitHub — source of this documentation