How to Fix / Troubleshooting

Safety first: Hot water can scald. Test water temperature carefully after adjustments.

Step 1 – Check cylinder size vs usage:
- Compare your Nibe cylinder capacity to household demand; multiple showers in quick succession may exceed capacity.
Step 2 – Inspect mixing valve:
- Ensure the thermostatic mixing valve is not stuck partially open to cold.
- Exercise the valve by turning from hot to cold several times.
Step 3 – Check cold inlet dip tube (if accessible):
- Some cylinders use an internal dip tube; if broken, cold water can mix at the top, reducing usable volume. This usually requires cylinder replacement or internal repair by a professional.
Step 4 – Verify heating cycle:
- Ensure the cylinder is fully reheated between high-demand periods.

If the issue is new and not related to increased usage, have a technician inspect internal components and stratification behavior.

Hot water runs out very quickly; initial water is hot but becomes cold after a short time.

Possible Causes