Safety: Turn off power. Hot water cylinders can be very hot; use gloves.

Locate DHW sensor: Find the sensor in the immersion pocket on the Hoval hot water cylinder or on the DHW outlet pipe.
Check insertion: Ensure the sensor is fully pushed into the pocket and secured.
Inspect wiring: Trace the cable to the furnace control panel, checking for damage. Tighten any loose terminals.
Reset and test: Restore power and clear the error. If the error persists, replace the DHW sensor.

Furnace shows DHW (domestic hot water) sensor error, no hot water production

Possible Causes