--- title: "De Dietrich HPI S 11 TR" description: "De Dietrich HPI S 11 TR heat pump connected to TapHome via Modbus RTU through BDR Thermea GTW-08 gateway." url: "https://taphome.com/en/compatibility/de-dietrich-hpi-s-11-tr/" language: en lastmod: 2026-03-20 generator: hugo ai: topics: ["modbus-rtu","heat-pump","rs485","gateway","zone-control","thermostat","hot-water"] questions: ["How to integrate De Dietrich HPI S 11 TR with TapHome?","What does the De Dietrich HPI TapHome template control?","How to connect De Dietrich heat pump via GTW-08 gateway to TapHome?","How to configure the GTW-08 Modbus address for TapHome?","What heating zones does the De Dietrich HPI template support?","How to monitor water pressure and temperatures on De Dietrich HPI via TapHome?"] --- # De Dietrich HPI S 11 TR Communication: Modbus RTU - [GTW-08 Configuration Manual (PDF)](https://tools.remeha.nl/wp-content/uploads/sites/11/2024/07/configuratiehandleiding-GTW-08.pdf) - [De Dietrich Official Website](https://www.dedietrich-heating.com) The De Dietrich HPI S 11 TR is an air/water heat pump that connects to TapHome via Modbus RTU through the BDR Thermea GTW-08 gateway. The GTW-08 is a communication module installed inside the heat pump's control PCB that bridges the appliance's internal L-Bus to an external RS-485 Modbus RTU interface. The TapHome template provides zone thermostat control for up to 7 heating zones, flow and return temperature monitoring, outdoor temperature, water pressure and system power readout. The same GTW-08 gateway and register map is shared across all BDR Thermea group appliances (De Dietrich, Remeha, Baxi). ## Hardware connection ### System overview ![GTW-08 Modbus gateway system overview — BMS to appliance connection via L-Bus](https://taphome.com/images/compatibility/de-dietrich-hpi-s-11-tr/gtw-08-overview-p004-004_hu_38cb3b7eae0b7644.jpg) The GTW-08 gateway sits between the BMS (TapHome) and the heating/cooling appliance. TapHome communicates with the gateway over RS-485, and the gateway communicates with the heat pump over the internal L-Bus. **Key components on the GTW-08 PCB:** - **1** — L-Bus connectors (connection to the appliance's main CU or EHC PCB) - **2** — DIP switches (baud rate and parity configuration) - **3** — Modbus connectors / X6 terminal (RS-485 to TapHome) - **4** — Communication status LEDs - **5** — Status LED (two-colour: green/red/orange) - **6** — Rotary knob (Modbus slave address) ### RS-485 wiring Connect TapHome to the GTW-08 gateway's **X6 Modbus connector** using a standard RS-485 cable: 1. Power off the heat pump 2. Access the control PCB unit inside the appliance 3. Connect the Modbus cable from TapHome to the GTW-08 X6 connector 4. Ensure the L-Bus cable is connected between the GTW-08 and the appliance's main CU or EHC PCB 5. Connect the L-Bus termination connector on the GTW-08 > [!WARNING] > **Important — Installation** > > The GTW-08 must be installed by a qualified professional. Always power off the appliance before accessing the control PCB. Follow all safety instructions in the appliance's installation manual. ## Enabling Modbus communication ### Gateway address (rotary knob) ![GTW-08 DIP switch configuration and LED status indications](https://taphome.com/images/compatibility/de-dietrich-hpi-s-11-tr/gtw-08-installation-p005-005_hu_a3049e7e88652a89.jpg) The rotary knob on the GTW-08 sets the Modbus slave address. The default position **0** corresponds to address **100**. | Position | Address | |----------|---------| | **0** | **100** (default) | | 1 | 101 | | 2 | 102 | | 3–9 | 103–109 | | A–F | 110–115 | **For TapHome:** Use the default address **100** (rotary knob position 0). Set the same slave address in the TapHome Modbus module configuration. ### DIP switch configuration The GTW-08 has 4 DIP switches for baud rate (switches 1–2) and parity (switches 3–4): **Baud rate (DIP 1–2):** | DIP 1 | DIP 2 | Baud rate | |-------|-------|-----------| | OFF | OFF | **9600** (default) | | ON | OFF | 19200 | | OFF | ON | 38400 | | ON | ON | 57600 | **Parity (DIP 3–4):** | DIP 3 | DIP 4 | Parity | |-------|-------|--------| | OFF | OFF | **None** (default) | | ON | OFF | Odd | | OFF | ON | Even | | ON | ON | None | **For TapHome:** Use the default settings — **9600 baud, no parity, 1 stop bit**. All DIP switches OFF. ### LED status indications | Colour | State | Meaning | |--------|-------|---------| | OFF | — | No power or defect | | Green | Continuous | Normal operation | | Green | Fast blinking (100 ms) | GTW-08 start-up phase | | Red | Fixed | No Modbus communication | | Orange | Fixed | No communication on L-Bus | | Orange | Slow blinking (500 ms) | GTW-08 Modbus error | **Normal state:** Green LED steady — the gateway is communicating on both L-Bus and Modbus. ## Device capabilities ### Temperature monitoring The template provides three temperature sensors reading from holding registers with automatic conversion: - **Outdoor Temperature** (H:384) — instantaneous outside temperature, with a service attribute showing the heating upper limit temperature (H:386) - **HP Flow Temperature** (H:403) — heat pump circuit flow temperature - **HP Return Temperature** (H:404) — heat pump circuit return temperature These three sensors use INT16 with 0.01 °C resolution (value / 100). Zone thermostat temperatures use a different conversion — see the zone section below. ### System monitoring - **Current System Power** (H:272) — actual power output of the system as a percentage (0–100%) from the consumer manager - **Water Pressure** (H:409) — primary circuit water pressure in bar (value / 10, range 0–3.0 bar) ### Zone thermostat control The template supports **7 independent heating zones**, each with its own thermostat device. Each zone thermostat reads the current zone temperature and allows setting the desired room temperature: - **Zone N Thermostat** — reads current zone temperature and writes room temperature setpoint - Each thermostat has 4 service attributes: zone short name, zone request type, zone function, and zone pump status Zone registers are calculated using a 512-register offset per zone: | Zone | Operating mode register | Setpoint register | Temperature register | |------|------------------------|-------------------|---------------------| | 1 | H:649 | H:664 | H:1105 | | 2 | H:1161 | H:1176 | H:1612 | | 3 | H:1673 | H:1688 | H:2129 | | 4 | H:2185 | H:2200 | H:2636 | | 5 | H:2697 | H:2712 | H:3148 | | 6 | H:3209 | H:3224 | H:3660 | | 7 | H:3721 | H:3736 | H:4172 | ### Zone operating mode Each zone has a separate operating mode control with three options: - **Scheduling** (0) — follows the appliance's built-in time program - **Manual** (1) — uses the manually set room temperature setpoint - **Off** (2) — zone is turned off ### Service diagnostics The module exposes 8 service attributes for system monitoring: - **Cascade Number** (H:7000) — shows whether the appliance is Master (1), Slave, or Not a Member (255) in a cascade setup - **Zone Count** (H:189) — number of zones detected in the system - **Deactivated Zone Count** (H:190) — number of deactivated zones - **Heating Zone Count** (H:191) — heating-only zones - **Heating+Cooling Zone Count** (H:192) — zones with heating and cooling - **DHW Zone Count** (H:193) — domestic hot water zones - **Process Heating Zone Count** (H:194) — process heating zones - **Pool Zone Count** (H:195) — pool zones ### Additional capabilities The GTW-08 gateway exposes many additional registers not included in the current template, including BMS power and temperature request control (H:256–259), system flow/return temperatures (H:400–401), exhaust gas temperature (H:402), DHW flow setpoint (H:408), main and sub status codes (H:411–412), actual relative power (H:413), pump speed (H:459), actual power in kW (H:460), instantaneous COP (H:9230), and comprehensive energy counters for CH, DHW and cooling consumption and delivery (H:433–451). Cascade management registers (H:7000+) are also available for multi-appliance setups. > [!TIP] > The BMS control registers (H:256–259) allow direct power and temperature demand control. To use them, add custom Modbus devices in TapHome: set Algorithm Type (H:258) to select control mode, then write Power Request (H:256) or Temperature Request (H:257) along with Heat Demand Type (H:259). ## Troubleshooting ### No Modbus communication (LED red) 1. **Check RS-485 cables** between TapHome and the GTW-08 X6 connector 2. Verify the rotary knob address matches the slave address configured in TapHome (default: 100) 3. Confirm TapHome is set to: **9600 baud, no parity, 1 stop bit** 4. Check DIP switch positions on the GTW-08 — all should be OFF for default settings 5. Power cycle the heat pump to restart the gateway ### No L-Bus communication (LED orange) 1. Check the L-Bus cable between the GTW-08 and the appliance's main CU or EHC PCB 2. Verify the L-Bus termination connector is installed on the GTW-08 3. Ensure the appliance is powered on and the control board is operational ### Zone not responding 1. Check the Zone Count service attribute — verify the zone is detected by the system 2. Verify the zone is not in the Deactivated Zone Count 3. Check the Zone Function service attribute — ensure the zone type matches the expected configuration (CH, DHW, Pool, etc.) 4. Try setting the zone operating mode to Manual and writing a temperature setpoint ### Gateway error (LED orange blinking) 1. Read register H:277 for error codes — 0 means no errors 2. Check registers H:531–547 for per-board error codes 3. Consult the appliance's service manual for specific error code meanings 4. If error code is 0xFFFE — the device board is not available ## Available devices De Dietrich HPI S 11 TR Module Service Attributes | | | |----------------------------|------------------------------------------------------------------------| | Cascade Number | reads H:7000 (UInt16); SWITCH: 1=Master, 255=Not a Member, other=Slave | | Zone Count | reads H:189 (UInt16); number of zones detected in the system | | Deactivated Zone Count | reads H:190 (UInt16); number of deactivated zones present | | Heating Zone Count | reads H:191 (UInt16); number of heating-only zones present | | Heating+Cooling Zone Count | reads H:192 (UInt16); number of heating+cooling zones present | | DHW Zone Count | reads H:193 (UInt16); number of domestic hot water zones present | | Process Heating Zone Count | reads H:194 (UInt16); number of process heating zones present | | Pool Zone Count | reads H:195 (UInt16); number of pool zones present | Current System Power Variable Read-only Actual power output of the system as percentage from consumer manager (0–100%) Register: H:272 Int16 Unit: % numeric HP Flow Temperature Temperature Sensor Read-only Heat pump circuit flow temperature Register: H:403 Int16 Unit: C numeric Zone 1 Operating Mode Multi-value Switch Zone 1 operating mode — Scheduling, Manual, or Off Register: H:0\*512+649 UInt16 numeric Values / States: Ruční · Ochrana proti zamrznutí Zone 2 Operating Mode Multi-value Switch Zone 2 operating mode — Scheduling, Manual, or Off Register: H:1\*512+649 UInt16 numeric Values / States: Ruční · Ochrana proti zamrznutí Zone 3 Operating Mode Multi-value Switch Zone 3 operating mode — Scheduling, Manual, or Off Register: H:2\*512+649 UInt16 numeric Values / States: Ruční · Ochrana proti zamrznutí Zone 4 Operating Mode Multi-value Switch Zone 4 operating mode — Scheduling, Manual, or Off Register: H:3\*512+649 UInt16 numeric Values / States: Ruční · Ochrana proti zamrznutí Zone 5 Operating Mode Multi-value Switch Zone 5 operating mode — Scheduling, Manual, or Off Register: H:4\*512+649 UInt16 numeric Values / States: Neaktivní · Ruční · Ochrana proti zamrznutí Zone 6 Operating Mode Multi-value Switch Zone 6 operating mode — Scheduling, Manual, or Off Register: H:5\*512+649 UInt16 numeric Values / States: Neaktivní · Ruční · Ochrana proti zamrznutí Zone 7 Operating Mode Multi-value Switch Zone 7 operating mode — Scheduling, Manual, or Off Register: H:6\*512+649 UInt16 numeric Values / States: Neaktivní · Ruční · Ochrana proti zamrznutí Zone 1 Thermostat Thermostat Zone 1 room thermostat — reads current temperature and sets desired temperature Register: H:0\*512+1105 → H:0\*512+664 UInt16 Unit: C numeric Zone 2 Thermostat Thermostat Zone 2 room thermostat — reads current temperature and sets desired temperature Register: H:1\*512+1100 → H:1\*512+664 Int16 Unit: C numeric Zone 3 Thermostat Thermostat Zone 3 room thermostat — reads current temperature and sets desired temperature Register: H:2\*512+1105 → H:2\*512+664 UInt16 Unit: C numeric Zone 4 Thermostat Thermostat Zone 4 room thermostat — reads current temperature and sets desired temperature Register: H:3\*512+1100 → H:3\*512+664 Int16 Unit: C numeric Zone 5 Thermostat Thermostat Zone 5 room thermostat — reads current temperature and sets desired temperature Register: H:4\*512+1100 → H:4\*512+664 UInt16 Unit: C numeric Zone 6 Thermostat Thermostat Zone 6 room thermostat — reads current temperature and sets desired temperature Register: H:5\*512+1100 → H:5\*512+664 Int16 Unit: C numeric Zone 7 Thermostat Thermostat Zone 7 room thermostat — reads current temperature and sets desired temperature Register: H:6\*512+1100 → H:6\*512+664 UInt16 Unit: C numeric Water Pressure Variable Read-only Primary circuit water pressure (0–3.0 bar) Register: H:409 Int16 Unit: bar numeric Outdoor Temperature Temperature Sensor Read-only Instantaneous outside temperature Register: H:384 Int16 Unit: C numeric Service Attributes | | |---------------------| | Heating Upper Limit | HP Return Temperature Temperature Sensor Read-only Heat pump circuit return temperature Register: H:404 Int16 Unit: C numeric **Connection:** Modbus RTU • 9600 baud• 8N1 • Slave ID: $\[SlaveId] Possible improvements (24) - H:256 Power Request — Power request 0–100% (UINT8, R/W). Key BMS control register — sets heat demand power level - H:257 Temperature Request — Temperature request (UINT16, 0.01C, R/W). Sets desired flow temperature for heat demand - H:258 Algorithm Type — 0=Remote management (temp+power), 1=Power, 2=Temperature, 3=Monitoring only. Determines BMS control level - H:259 Heat Demand Type — 0=Standby, 7=Heating, 8=Cooling. Activates/deactivates heat production - H:275 Heat Demand Bitfield — Bitfield: zones allowed, cooling, DHW, heat engine active. Useful for diagnostics - H:277 Error List — List of errors for all connected devices (UINT16, 0–65535) - H:279 Output Status 2 (byte 1) — Bitfield: flame on, HP on, backup 1/2 on, DHW backup, service required, power down, water pressure low - H:280 Output Status 2 (byte 2) — Bitfield: pump, 3-way valve open/close, DHW active, CH active, cooling active - H:385 Seasonal Mode — ENUM8: 0=Winter, 1=Frost protection, 2=Summer neutral, 3=Summer - H:400 System Flow Temperature — System flow temperature (INT16, 0.01C, display code AM016). Different from HP flow (403) - H:401 System Return Temperature — Return temperature of water entering appliance (INT16, 0.01C, display code AM018) - H:402 Exhaust Gas Temperature — Temperature of exhaust gas leaving appliance (INT16, 0.01C, -20..120, display code AM036) - H:408 DHW Flow Setpoint — Flow temperature setpoint for domestic hot water (UINT16, 0.01C, display code DM004) - H:411 Main Status — ENUM8: 0=Standby, 1=Heat demand, 3=Generator CH, 4=Generator DHW, 7=Cooling, 9=Blocking, 10=Locking, 16=Frost protection, etc. - H:412 Sub Status — ENUM8: detailed sub-status (60+ values) — anti-cycling, defrost, compressor states, backup control - H:413 Actual Relative Power — Actual relative power of appliance (UINT16, %, 0–100, display code AM024) - H:459 Pump Speed — Current pump speed (UINT16, 0.1%, R/W, display code AM010) - H:460 Actual Power kW — Actual power of appliance (UINT32, 0.01 kW, display code AM047) - H:9230 Instantaneous COP — Calculated instantaneous COP (UINT16, 0.001, display code HM031). Key efficiency metric - H:433 Energy Consumed CH — UINT32 (2 registers), energy consumed for central heating in kWh - H:435 Energy Consumed DHW — UINT32 (2 registers), energy consumed for domestic hot water in kWh - H:443 Total Thermal Energy Delivered — UINT32 (2 registers), total thermal energy delivered in kWh - H:445 Thermal Energy CH — UINT32 (2 registers), thermal energy delivered for central heating in kWh - H:447 Thermal Energy DHW — UINT32 (2 registers), thermal energy delivered for domestic hot water in kWh ## Sources - GTW-08 Modbus Configuration Manual [tools.remeha.nl](https://tools.remeha.nl/wp-content/uploads/sites/11/2024/07/configuratiehandleiding-GTW-08.pdf) 2026-03-20 [PDF](https://taphome.com/compatibility/devices/de-dietrich-hpi-s-11-tr/manufacturer/gtw-08-configuration-manual.pdf) - De Dietrich / BDR Thermea GTW-08 Registers (EVCC) [github.com](https://github.com/evcc-io/evcc/issues/25470) 2026-03-20 ## Related Documentation - [Modbus Integration](https://taphome.com/en/compatibility/modbus-guide/) - [Modbus](https://taphome.com/en/docs/integration/modbus/) - [Simple configuration using templates](https://taphome.com/en/docs/integration/modbus/templates/) - [Modbus scripts and prefetch](https://taphome.com/en/docs/script/modbus-scripts/) - [Modbus functions](https://taphome.com/en/docs/script/modbus/) - [Modbus data types](https://taphome.com/en/docs/script/modbus-data-types/)