Boiler issue: No hot water but heating still works

Do you still have heating, but no hot water from the taps? If so, there is likely an issue with your boiler. This problem is more common than you might think and is usually traced back to a specific component in the boiler. Common causes include a faulty diverter valve, a broken heat exchanger, or a malfunction in the hot water control system.

In this blog, we explain possible causes, what you can check yourself, and when it’s time to call a professional. If you currently have no hot water but your heating works, read on to find out what you can do.

Summary

• If the heating works but hot water is absent, there is often a fault in the boiler’s hot water function.
• Possible causes include a defective diverter valve, broken heat exchanger, control system error, or low water pressure.
• Sometimes the hot water function may have been accidentally turned off, or there could be an issue with the thermostat.
• First, check the water pressure and thermostat settings, and reset the boiler if necessary.
• If these steps don’t resolve the issue, contact a certified technician to prevent further damage or system failure.
• Proper maintenance often prevents these problems and extends the life of your boiler.
  
  

Why Do I Have Heating but No Hot Water?

If your home is still being heated but you get no hot water from the taps, it’s likely that there is an issue with your boiler. In many cases, the problem specifically affects the hot water function while the heating continues to work normally. Possible causes include:

• Boiler malfunction: An internal fault may prevent the boiler from supplying hot water. Modern boilers often display an error code indicating the source of the problem.
• Thermostat issues: Some systems have separate controls for hot water. If the thermostat is incorrectly set or malfunctioning, it can affect hot water supply.
• Hot water function failure: The diverter valve, which switches between heating and hot water, may be stuck or broken, causing the boiler to send heat only to the radiators.
• Power interruption: A disruption in the power supply to certain boiler components can stop the hot water system from working while the heating remains operational.
  
  

No hot water but heating works: possible causes

You can follow this step-by-step guide to determine the cause of the problem and whether you can fix it yourself or need to call a professional.

Step-by-step troubleshooting

1. Check the thermostat: First, check if the thermostat display is working. If the screen is off or blinking, the batteries may be dead. Replace them according to the thermostat manual. Without a working thermostat, the boiler cannot operate correctly.
2. Check the hot water function: Ensure the boiler’s hot water function is activated. If it is turned off, only cold water will flow from the taps. The boiler manual explains how to check and reactivate this function.
3. Check the boiler water pressure: The boiler needs sufficient water pressure to operate properly. Ideal pressure is between 1.2 and 2 bar, which can be read on the display or manometer. If the pressure is too low, refill according to the manual.
4. Ensure the boiler has power: Check whether the boiler is receiving electricity. You can test the socket with another device. If the socket is not working or the boiler appears unpowered, contact a technician or electrician.
5. Reset the boiler: Sometimes a simple reset can resolve the fault. Most boilers have a reset button or function on the control panel. Follow the manual and wait a few minutes to see if the boiler restarts correctly.
6. Check the error code: If the boiler displays an error code, note it and refer to the manual to determine its meaning. This can indicate the problem and whether you can fix it yourself. You can also provide the code to a technician for guidance.
7. Call a professional if needed: If you cannot resolve the issue or the fault persists, contact a certified technician to repair it safely.
   
   

Conclusion: prevent boiler issues with proper maintenance

If you have followed all steps but still have no hot water, it is wise to call a professional to resolve the issue safely and efficiently. Have your boiler serviced at least every two years to prevent future problems. Regular maintenance ensures reliable, energy-efficient operation, allowing you to enjoy a fully functioning boiler for as long as possible.