• Requires HA Core 2026.8.0 or later, supports 2026.10.x

Overview

ramses_cc is a Home Assistant custom integration that works with RAMSES II-based RF 868 Mhz systems for (heating) CH/DHW (e.g. Honeywell Evohome) and (ventilation) HVAC (e.g. Itho Spider, Orcon).

Note

Ramses RF can not interpret the new Honeywell Ramses-III (R3) messages used after a firmware upgrade since 2025 and (some) new devices.

This includes CH/DHW systems such as evohome, Sundial, Hometronic, Chronotherm and others.

The simplest way to know if it will work with your CH/DHW system is to identify the box connected to your boiler (or other heat source) to one of (there will be other systems that also work):

• R8810A or R8820A: OpenTherm Bridge
• BDR91A or BDR91T: Wireless Relay
• HC60NG: Wireless Relay (older hardware version)

ramses_cc also works with HVAC (ventilation) systems using the Ramses-II protocol, such as from Itho, Orcon, Nuaire, Ventiline, Vasco, etc.

It uses the ramses_rf client library to decode the RAMSES-II protocol used by these devices. Note that other systems may also use this protocol. YMMV!

The library requires a USB-to-RF device, either a Honeywell HGI80 (rare, expensive) or a USB/MQTT dongle running ramses_esp or evofw3, such as the one from here or your own ESP32-S3-WROOM-1 N16R8 with a CC1100 transponder.

Our Code of Conduct applies to all use of this repository and the code it creates.

Prerequisites

1. Obtain a USB-to-RF transceiver — either a Honeywell HGI80 or a USB/MQTT dongle running ramses_esp or evofw3.
2. Connect the transceiver to your Home Assistant host (USB) or network (MQTT).
3. Ensure you are running HA Core 2026.8.0 or later.

Installation

Via HACS

1. Open HACS in Home Assistant.
2. Go to Integrations > Explore & Download Repositories.
3. Search for ramses_cc and install it.
4. Restart Home Assistant.

Manual

1. Copy the custom_components/ramses_cc/ folder from this repository into your custom_components/ directory.
2. Restart Home Assistant.

Configuration

1. Go to Settings > Devices & Services > Add Integration.
2. Search for ramses_rf (the integration name).
3. Select your transceiver port (USB or MQTT) and configure the serial/MQTT settings.
4. Complete the config flow — the integration will start a passive scan to discover devices.
5. See the wiki for detailed configuration of the system schema.

Installation Parameters

Parameter	Type	Required	Description
Transceiver Hardware	Hardware	Yes	Honeywell HGI80, SSM-D2 / evofw3 dongle, or Indalo Tech ramses_esp (ESP32-S3).
Local USB Port	String / Path	Optional	Path to local serial port (e.g. /dev/serial/by-id/usb-Texas_Instruments..., COM3). Baud rate 115200 (evofw3/ramses_esp) or 57600 (HGI80).
Network Serial Port	URI / URL	Optional	Remote serial socket using rfc2217://<host>:<port>, socket://<host>:<port>, or tcp://<host>:<port>.
Home Assistant MQTT	Service	Optional	Built-in Home Assistant MQTT integration bridge with broker topic subscription.
Standalone MQTT	URI / URL	Optional	Custom Paho MQTT broker connection string (mqtt://[user:pass@]<host>[:port]).
Zigbee Bridge	URI / URL	Optional	Zigbee coordinator bridge URI (zigbee://<ieee_address>/<cluster>/<attribute>).

Configuration & Options Parameters

Option Parameter	Type	Default	Description
scan_interval	Integer (seconds)	1200	Periodic polling interval (in seconds) for supported passive parameter queries.
packet_log	File Path	None	Absolute path to a file where raw RAMSES II protocol packet logs are recorded.
restore_cache	Boolean	True	Restore learned device traits and schema from cache upon startup.
advanced_features	Boolean	False	Enable advanced entity creation (e.g. packet debug event entities).
message_events	Boolean	False	Dispatch RAMSES RF packet message events on Home Assistant's event bus.
known_list	Dictionary	{}	Explicit list of authorized device IDs and optional device class / faked traits.
block_list	Dictionary	{}	Explicit list of device IDs to ignore/block from discovery and packet processing.
system_schema	Dictionary	{}	Declarative schema defining controller (CTL), heating/cooling zones, and ventilation topology.

Removal

1. Go to Settings > Devices & Services.
2. Find the ramses_rf integration and select it.
3. Click Delete to remove the config entry and all its entities.
4. If installed via HACS, optionally remove it from HACS > Integrations.
5. If installed manually, delete the custom_components/ramses_cc/ folder.
6. Restart Home Assistant.

Actions

This integration provides the following Actions (in Tools > Actions). Search for "ramses" in Developer Tools > Actions in your Home Assistant instance to get the full list plus an interactive UI.

HVAC / Ventilation

Service	Description	Fields
get_fan_param	Request value of a configuration parameter (2411) from a FAN	fan_device/fan_id, param_id, from_id
set_fan_param	Set a configuration parameter (2411) on a FAN	fan_device/fan_id, param_id, value, from_id
update_fan_params	Request all configuration parameters (2411) from a FAN	fan_device/fan_id, from_id
add_faked_rem	Create a faked REM (virtual remote) for sending commands to a FAN	device_id, bound_to, alias
send_command	Send a RAMSES command as if from a remote	command, num_repeats, delay_secs
learn_command	Learn a RAMSES command and add it to the database	command, timeout
add_command	Add a RAMSES command to the database until restart	command, packet_string
delete_command	Delete a RAMSES command from the database	command
send_packet	Send a completely bespoke RAMSES II command packet from the gateway (Enable Send Packet Config)	device_id, from_id, verb, code, payload

Heat / CH / DHW

Service	Description	Fields
bind_device	Bind a device to a CH/DHW controller or a fan/ventilation unit	device_id, offer, confirm, device_info
force_update	Immediately update the system state
get_system_faults	Obtain the controller's latest fault log	num_entries
reset_system_mode	The system will be in auto mode and all zones in follow_schedule mode
set_system_mode	The system will be in the new mode and all zones not in permanent_override mode will be affected	mode, period, duration
get_zone_schedule	Obtain the zone's latest weekly schedule (only evohome)
reset_zone_config	Reset the configuration of the zone
reset_zone_mode	Reset the operating mode of the zone
set_zone_config	Set the configuration of the zone	min_temp, max_temp
set_zone_mode	Set the operating mode of the zone, indefinitely or for a duration	mode, setpoint, duration, until
set_zone_schedule	Upload the zone's weekly schedule	schedule
get_dhw_schedule	Obtain the DHW's latest weekly schedule
reset_dhw_mode	Reset the operating mode of the system's DHW
reset_dhw_params	Reset the configuration of the system's DHW
set_dhw_boost	Enable the system's DHW for an hour
set_dhw_mode	Set the operating mode of the system's DHW	mode, active, duration, until
set_dhw_params	Set the configuration of the system's DHW	setpoint, overrun, differential
set_dhw_schedule	Upload the DHW's weekly schedule	schedule

Sensors / Fake data

Service	Description	Fields
fake_zone_temp	Set the current temperature (not setpoint) of an evohome zone	temperature
fake_dhw_temp	Set the current temperature (not setpoint) of an evohome water heater	temperature
put_zone_temp	Fake the sensor temperature of a zone (replaces deprecated fake_sensor_temp)	temperature
put_room_temp	Announce the measured room temperature of an evohome zone sensor	temperature
put_dhw_temp	Announce the measured temperature of an evohome DHW sensor	temperature
put_co2_level	Announce the measured CO2 level of an indoor sensor	co2_level
put_ventilation_demand	Send a transient 0-100% demand from a faked CO2 sensor to its bound Orcon ventilation unit	ventilation_demand
put_indoor_humidity	Announce the measured relative humidity of an indoor sensor	indoor_humidity

Device management / Discovery

Service	Description	Fields
discover_known_devices	Call all devices in the Known List, returning a report in your system log	device_id
sync_topology	Immediately sync the learned topology to the config entry
get_discovered_devices	Retrieve the list of devices discovered by the passive scan	status, enabled
accept_discovered_device	Accept a discovered device and add it to the schema	device_id, owner, schema_entry
discard_discovered_device	Discard a discovered device. It stays in the list for spam prevention	device_id
remove_discovered_device	Mark a previously accepted device as removed	device_id
enable_discovered_device	Enable a disabled or discarded device without changing its status	device_id
disable_discovered_device	Disable an accepted device temporarily (e.g. for maintenance)	device_id
remove_device	Remove a device from the schema and HA device registry e.g. when replaced	device_id
set_polling_interval	Configure or reset the effective polling interval for a RAMSES device	device_id, polling_interval

Additionally, there are Home Assistant's built-in services for climate HEAT/HVAC.

More in the Wiki

See the ramses_cc wiki for installation, configuration, troubleshooting, etc. The Wiki Config System Schema page explains the Passive Device Scan tool and Migrating from an earlier version.