--- title: "Dantherm HCV Air Recovery" description: "Dantherm HCV 300-700 heat recovery ventilation units connected to TapHome via Modbus TCP." url: "https://taphome.com/en/compatibility/dantherm-air-recovery/" language: en lastmod: 2026-10-08 generator: hugo ai: topics: ["modbus-tcp","air-recovery","heat-recovery-ventilation","ethernet","bitmask-encoding"] questions: ["How to integrate Dantherm HCV with TapHome?","What does the Dantherm Air Recovery TapHome template measure and control?","How to connect Dantherm HCV via Modbus TCP to TapHome?","How to activate Fireplace mode on Dantherm HCV via TapHome?","Why are mode changes not applied during defrost on Dantherm HCV?","What fan speed levels are available for the Dantherm HCV in TapHome?"] --- # Dantherm HCV Air Recovery Communication: Modbus TCP - [Dantherm Official Website](https://www.dantherm.com/en/products/air-handling-units/) The Dantherm HCV series (300, 400, 460, 500, 700) are mechanical ventilation heat recovery (MVHR) units with thermal efficiency above 90%. TapHome connects directly to the unit via Modbus TCP over Ethernet — no additional gateway is required. The template provides operating mode control, fan level adjustment (0–4), fan RPM monitoring, outdoor temperature reading, and dedicated switches for Away and Fireplace modes. ## Network connection The HCV unit has an RJ45 Ethernet port (LAN) on the main PCB. Connect it to the same local network as TapHome Core using a standard Ethernet cable. - **Protocol:** Modbus TCP - **Port:** 502 - **Default Slave ID:** 1 - **Byte order:** Little-endian (word swap) > [!WARNING] > The RS-485 port (J19) on the PCB is reserved for internal Dantherm accessories only. External systems such as TapHome must use the **Ethernet/LAN port** for Modbus TCP communication. ### PCB connections ![Dantherm HCV main PCB connector layout](https://taphome.com/images/compatibility/dantherm-air-recovery/pcb-connections_hu_16d277ca6e5e5c64.jpg) Key connectors relevant for TapHome integration: | Connector | Function | |-----------|----------| | **LAN** | Ethernet — Modbus TCP communication with TapHome | | **J19** | RS-485 — internal Dantherm accessories only | | **J1** | Digital inputs — external fan speed override (optional) | | **USB** | Service connection for PC Tool | ## Configuration No special configuration is needed on the HCV unit. The Ethernet port is active by default with Modbus TCP on port 502. When importing the template in TapHome, provide: - **IP Address** — the unit's IP on the local network (default: 192.168.0.1) - **Slave ID** — Modbus slave address (default: 1) > [!TIP] > Assign a static IP address to the HCV unit in the router's DHCP settings to prevent the address from changing after a power cycle. ## Device capabilities The template exposes the following devices: ### Operating mode control Three mode devices are provided: - **Mode (multi-value switch)** — select from: Standby, Demand, Manual, Week Program, Away, Fireplace, Summer. Uses register H:168 with bitmask encoding for both reading and writing. - **Mode (numeric variable)** — reads the current mode as a numeric value from H:168 and writes to H:170. Useful for automation rules that need numeric mode values. - **Current State** — read-only sensor showing the active operating mode from register H:472. This reflects the actual running mode, including system-initiated states like Defrost. ### Fan control - **Ventilation (multi-value switch)** — fan level 0–4 via register H:324. Level 0 turns fans off, levels 1–4 correspond to increasing airflow. - **RPM Fan 1 / RPM Fan 2** — read-only sensors showing actual fan speeds in RPM from registers H:100 and H:102 (LittleEndianFloat). ### Quick mode switches - **Away Mode** — toggle switch for Away mode (bitmask 0x10 on register H:168) - **Fireplace Mode** — toggle switch for Fireplace mode (bitmask 0x40 on register H:168). Fireplace mode creates positive pressure by increasing supply airflow relative to extract. ### Temperature monitoring The template includes outdoor temperature reading from register H:132 (LittleEndianFloat). The HCV unit measures up to 5 temperatures internally — only T1 is currently included in the template: | Register | Sensor | Description | In template | |----------|--------|-------------|-------------| | H:132 | T1 | Outdoor air temperature | Yes | | H:134 | T2 | Supply air temperature | No | | H:136 | T3 | Extract air temperature | No | | H:138 | T4 | Exhaust air temperature | No | | H:140 | Room | Room temperature (optional sensor) | No | > [!NOTE] > Temperature sensor assignments depend on the Operating Mode switch (A/B) on the PCB. In Mode B, the physical sensor mapping is swapped — S1 reads extract air instead of outdoor air. Verify the switch position matches the installation. ### Additional device capabilities The HCV units also expose Modbus registers for filter management (remaining days, lifetime, reset), bypass damper status, humidity monitoring (with optional RH sensor), alarm status and CO2 levels (with optional CO2 sensor via HAC controller). These can be added to the TapHome template in a future update. ## Troubleshooting ### No Modbus communication 1. Verify the Ethernet cable is connected to the LAN port (not USB or J19) 2. Confirm the unit's IP address — check the router's DHCP lease table 3. Ensure TapHome Core and the HCV unit are on the same network/subnet 4. Check that no firewall is blocking port 502 ### Mode changes not applied The unit ignores mode write commands during **Defrost**. Wait for the defrost cycle to complete before changing modes. Current state (H:472) will show value 15 during active defrost. ### Incorrect temperature readings Check the A/B operating mode switch position on the PCB (SW2). The sensor-to-register mapping differs between Mode A and Mode B — an incorrect switch position will show swapped temperature values. ## Available devices Dantherm Air Recovery Module Current State Variable Read-only Active operating mode including system-initiated states (e.g. Defrost, Night) Register: H:472 UInt16 numeric Mode Multi-value Switch Operating mode selector — Standby, Demand, Manual, Week Program, Away, Fireplace, Summer Register: H:168 LittleEndianInt32 bitmask Values / States: Standby · Demand Mode · Manual Mode · Week Program Mode · Away Mode · Fireplace Mode · Summer Mode · Other Mode (numeric) Variable Numeric mode variable — reads active mode from H:168, writes to dedicated register H:170 for automation rules Register: H:168 → H:170 LittleEndianInt32 numeric Ventilation Multi-value Switch Fan level 0–4 (off, min, low, medium, high) Register: H:324 LittleEndianInt32 numeric Values / States: Level 0 · Level 1 · Level 2 · Level 3 · Level 4 Away Switch Register: H:168 UInt16 bitmask Values / States: ON · OFF RPM Fan 1 Variable Read-only Supply fan speed Register: H:100 LittleEndianFloat Unit: RPM Outdoor Temperature Variable Read-only Register: H:132 LittleEndianFloat Unit: °C RPM Fan 2 Variable Read-only Extract fan speed Register: H:102 LittleEndianFloat Unit: RPM Fireplace Mode Switch Positive pressure mode — increases supply fan, reduces extract fan Register: H:168 LittleEndianInt32 bitmask Values / States: ON · OFF Away Mode Switch Register: H:168 LittleEndianInt32 bitmask Values / States: ON · OFF **Connection:** Modbus TCP • Slave ID: $\[SlaveId] Possible improvements (15) - H:134 Supply Temperature (T2) — Float32, °C, read-only - H:136 Extract Temperature (T3) — Float32, °C, read-only - H:138 Exhaust Temperature (T4) — Float32, °C, read-only - H:140 Room Temperature — Float32, °C, optional sensor - H:196 Humidity — UInt32, %, requires RH sensor accessory - H:198 Bypass Damper — UInt32, 0=Closed, 1=Opened, 2=InProgress - H:430 Air Quality — UInt32, requires VOC/CO2 sensor - H:516 Alarm — UInt32, alarm status - H:554 Filter Remaining — UInt32, days remaining - H:556 Filter Lifetime — UInt32, days, R/W - H:558 Filter Reset — Write to reset filter counter - H:514 Alarm Reset — Write to reset alarm - H:160 Internal Preheater Duty Cycle — Int32, % - H:574 CO2 Level — UInt32, ppm, requires CO2 sensor via HAC controller - H:624 Work Time — UInt32, total operating hours ## Sources - Dantherm HCV 300-700 User & Service Manual [danthermpublicfiles.blob.core.windows.net](https://danthermpublicfiles.blob.core.windows.net/en-dantherm-manuals/Dantherm-HCV-300-400-460-500-700-user-service-manual-108661-EN.pdf) 2026-03-12 [PDF](https://taphome.com/compatibility/devices/dantherm-air-recovery/manufacturer/service-manual.pdf) ## 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/)