Low hot water temperature or no hot water

What does Low/No hot water mean?

The NIBE F750 is not producing hot water at the desired temperature, or there is a complete lack of hot water. This can be due to valve positions, system settings, or usage patterns.

• The hot water heater filling valve (QM10) is closed or choked.
• The mixing valve (if installed) is set too low.
• The heat pump is in an incorrect operating mode (e.g., 'auto' with low 'stop additional heat' or 'manual' without 'addition').
• High hot water consumption has depleted the available supply.
• The hot water comfort setting is too low.
• Hot water prioritization in settings is too low or not configured correctly.

Click steps to track your progress.

1. 1

   Check that the filling valve (QM10) for the hot water heater is fully open.

2. 2

   If a mixing valve is installed, verify its setting and adjust it upwards to increase hot water temperature.

3. 3

   Access menu 4.2 to check the operating mode; if 'auto', increase the 'stop additional heat' value in menu 4.9.2. If 'manual', select 'addition'.

4. 4

   If there's been high hot water use, wait for the system to reheat. You can activate 'temporary lux' in menu 2.1 for a temporary boost.

5. 5

   Go to menu 2.2 and select a higher comfort mode for hot water.

6. 6

   In menu 4.9.1, increase the time period for which hot water production is prioritized (be aware this may reduce heating for rooms).