verified connector library

Stiebel Eltron WPM3 heat pumps (needs ISG web gateway, Modbus TCP)

Register map(s) for this device, each at the trust rung it earned. Addresses are 0-based as on the wire; word order and scaling are only confirmed at the hardware-verified rung.

interop-verified

Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.

pointaddress (0-based)typescaleunit
actual_temperature_fe7500I160.1°C
set_temperature_fe7501I160.1°C
outside_temperature506I160.1°C
actual_temperature_hk_1507I160.1°C
set_temperature_hk_1508I160.1°C
actual_temperature_hk_2510I160.1°C
set_temperature_hk_2511I160.1°C
actual_flow_temperature_wp512I160.1°C
actual_flow_temperature514I160.1°C
actual_return_temperature515I160.1°C
actual_buffer_temperature517I160.1°C
heating_pressure519I160.01bar
flow_rate520I160.1l/min
actual_temperature_dhw521I160.1°C
set_temperature_dhw522I160.1°C
source_temperature535I160.1°C
source_pressure537I160.01bar
hot_gas_temperature538I160.1°C
high_pressure539I160.1bar
low_pressure540I160.1bar
operating_mode1500U161
comfort_temperature_hk11501I160.1°C
eco_temperature_hk11502I160.1°C
comfort_temperature_dhw1509I160.1°C
eco_temperature_dhw1510I160.1°C

link settings as documented (unverified): TCP; unit ID 1; FC 03,04,06,16; ISG standard IP address: 192.168.0.126, TCP port: 502, Slave ID: 1 (permanent). ISG addresses are 1-based.

⚠ Incorrect use can result in damage to the connected integral ventilation unit or heat pump. For safety reasons, faults can only be acknowledged via the SERVICEWELT user interface. — Starkest reads only; we never write a control register.

bench facts as documented (unverified)
connectorRJ45
wiring notesIP network connection to the ISG and to the building management system
broadcastnot supported
sentinel values32768 (0x8000H) for unavailable objects
protocol notesFor appliances of the LWZ series, the WPM displays substitute values '-60' (sensor lead missing/disconnected) and '-50' (short circuit of sensor lead).
identification notesChecking the software version: SERVICEWELT under DIAGNOSIS -> SYSTEM -> ISG
firmware applicabilityWPM 3 with software version 39005 or higher, and WPM3i with software version 39106 or higher.

generated by gemini:gemini-3.5-flash · harvested from https://www.stiebel-eltron.com.au/download/1685919441_321798-44755-9770_ISG%20Modbus_en.pdf (Stiebel Eltron); manual-faithful — the document's claims, panel risk: ELEVATED — panel is not confident; proved interop-verified on 2026-06-11 · recorded 2026-06-11

The trust ladder

Each rung states what it proved and what it did not. Gray until proven; green is earned by hardware only.

Have a device that isn't here? Upload its register map — generation is free, and the connector earns its rung by being proven, not claimed.

Need it proven on your own device? Hardware verification — if it doesn't verify, you don't pay.

Building a platform? License the verified library — machine-readable maps, firmware matrix, API access.