Atrea DUPLEX series are mechanical ventilation heat recovery (MVHR) units controlled by the RD5 regulation system. TapHome connects directly to the RD5 controller via Modbus TCP over Ethernet — no additional gateway is required.
The template provides thermostat control with temperature setpoint, operating mode selection (Off, Auto, Ventilation, Circulation, Night Precooling, Balance, Overpressure), fan power adjustment (0–100%), four temperature sensors (supply, indoor, outdoor, extract), and comprehensive diagnostics with 45+ error and warning registers.
Network connection
The RD5 controller has a built-in Ethernet interface. Connect it to the same local network as TapHome Core using a standard Ethernet cable.
- Protocol: Modbus TCP
- Port: 502
- Slave ID: 1–255 (configurable)
- Data encoding: Int16, temperature values divided by 10
Enabling Modbus TCP
Modbus TCP must be explicitly enabled in the RD5 service settings before TapHome can communicate with the unit.
Navigate to service parameter 3.15.1 Modbus TCP and set it to YES.
If Modbus TCP is not enabled (parameter 3.15.1 = NO), the RD5 controller will not respond to any Modbus TCP requests on port 502.
Configuration
When importing the template in TapHome, provide:
- IP Address — the RD5 controller’s IP on the local network
- Slave ID — Modbus appliance address (default: 1)
Assign a static IP address to the RD5 controller in the router’s DHCP settings to prevent the address from changing after a power cycle.
The manufacturer recommends using the Manual control routine when the unit is controlled from a BMS system such as TapHome. The template writes control registers (H:10708, H:10709, H:10710) that correspond to the Manual routine (H:10700–H:10703 = 0).
Device capabilities
The template exposes the following devices:
Thermostat
- Atrea Thermostat — room temperature control with setpoint range 10–40 °C. Reads current temperature from I:10212 (T-SUP), reads desired temperature from H:10716, and writes the setpoint to H:10710. Includes 13 service attributes showing heating/cooling status (water valve, pump, heat pump, preheating, cooling configuration) and 6 service actions for configuring primary/secondary heating, preheating, cooling, capillary freezing protection, and room control sensor selection.
Operating mode control
- Mode Control — multi-value switch for selecting the operating mode via registers H:10705 (read) / H:10709 (write). Available modes: Off, Auto, Ventilation, Circulation + Ventilation, Circulation, Night Precooling, Balance, Overpressure.
Fan control
- Ventilation — dimmer controlling fan power from 0% (off) to 100% via registers H:10704 (read) / H:10708 (write). The minimum active power is 12%. Includes 4 service attributes (M1 output %, M2 output %, regulation mode, ventilation interval) and 2 service actions (fan regulation mode selection, ventilation interval setting 0–60 min).
Temperature monitoring
The template includes four temperature sensors:
| Sensor | Register | Description |
|---|---|---|
| T-SUP (Supply) | I:10212 | Supply air temperature — air delivered to rooms after heat recovery |
| T-IDA (Indoor) | I:10215 | Indoor air temperature — source selectable between CP Touch, T-ETA, TRKn, or BMS |
| T-ODA (Outdoor) | I:10211 | Outdoor air temperature — built-in sensor or BMS-provided value |
| T-ETA (Extract) | I:10213 | Extract air temperature — air extracted from rooms before heat recovery |
The T-IDA sensor source can be configured via the service action on the Indoor Air Temperature device. The T-ODA sensor can be switched between the built-in sensor and a BMS-provided value, with configurable sensor position (internal/external).
Module-level diagnostics
The RD5 template monitors 45+ discrete registers (D:11100–D:11184) for errors and warnings, including:
- Errors: Device overheating, orientation not set, sensor failures (TU1/TU2/TEa/TEb/TA2/T-ODA/T-ETA), STP contact, manometer failures, RD-IO communication, unbalanced flow, configuration missing, insufficient preheating, module failures, frost protection
- Warnings: Heat exchanger freezing/defrosting, high tariff, insufficient flow/heating, clogged filter, input alarm faults, uncommissioned unit, safe mode, cooling/heating unavailable
A module-level service attribute shows the Unit Orientation (which motor is the supply fan), and a service action allows configuring the supply fan assignment (M1 or M2).
Additional capabilities
The RD5 units also expose Modbus registers for exhaust air temperature (T-EHA), forced mode status, season control, volume flow monitoring (supply/extract), filter replacement period, alarm/filter reset, and control routine configuration. These can be added to the TapHome template in a future update.
Troubleshooting
No Modbus communication
- Verify that Modbus TCP is enabled — parameter 3.15.1 Modbus TCP = YES in the service settings
- Confirm the RD5 controller’s IP address — check the router’s DHCP lease table
- Ensure TapHome Core and the RD5 controller are on the same network/subnet
- Check that no firewall is blocking port 502
- Respect the 5-second gap between multiple read/write operations as recommended by the manufacturer
Temperature values appear incorrect
Temperature registers use Int16 encoding with the value divided by 10. Values above 32767 represent negative temperatures: (value - 65536) / 10. For example, value 65516 = (65516 - 65536) / 10 = -2.0 °C.
Mode changes not applied
When the unit is in a forced mode (startup, run-down, defrost, D1–D4 input activation), mode write commands may be ignored. Check the forced mode register H:10712 — value 0 means no forced mode is active.
If using the Schedule control routine (H:10700–H:10703 = 1), you must first write value 2 to the corresponding control routine register before writing the new control parameter.
