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Troubleshooting Guide: Hot Water But No Heating - Common Causes and Solutions

Is your boiler producing hot water but failing to heat your home? This comprehensive guide will help you understand why this common problem occurs and what steps you can take to resolve it. At QF Maintenance, our experienced heating engineers have dealt with countless similar situations and are here to share their expertise.


Understanding Your Boiler System


Modern boiler systems are designed to handle both hot water and heating independently. This means you can have hot water even when your heating isn't working properly. While this feature is convenient, it can also make troubleshooting more challenging when issues arise.


Quick Fixes You Can Try First


Before calling a professional, there are several simple checks you can perform:


1. Check Your Boiler Settings


Many homeowners accidentally leave their boiler in "hot water only" mode, especially after summer. Verify your boiler's control panel is set to provide both hot water and heating. This is particularly important for combi boiler owners.


2. Verify Timer Settings


With seasonal changes and daylight savings, your boiler's timer might need adjustment. Ensure your automatic timer settings match your current schedule and heating needs. Take a moment to check both the time and heating periods are correctly programmed.


3. Inspect Your Thermostat


A thermostat set too low won't trigger your heating system. Check your thermostat's temperature setting and consider raising it slightly to test if your heating responds. Remember that room thermostats are separate from your boiler's control panel.


4. Review Individual Radiator Settings


Many modern homes have thermostatic radiator valves (TRVs) that control individual radiators. These white valves at the bottom of each radiator should be set appropriately or synced with your main thermostat for optimal performance.


Common Technical Issues


If basic checks don't resolve the problem, these technical issues might be the cause:


Radiator Problems


If your radiators feel lukewarm or have cold spots, they likely need:


  • Bleeding to remove trapped air

  • Professional power flushing to remove sludge buildup

  • System rebalancing for optimal heat distribution


Ignition Lead Faults


A failing ignition lead prevents your boiler from lighting properly. Listen for clicking sounds when the heating tries to start - this could indicate an ignition problem. While replacement parts are relatively affordable (starting around £200), this job requires a qualified engineer.


Burner Blockages


Carbon buildup on your boiler's burner can severely impact heating performance. Regular maintenance can prevent this issue, but if left unchecked, you may need a complete burner replacement (costs starting from £250).


Diverter Valve Issues


For combi boiler owners, a faulty diverter valve often explains why hot water works but heating doesn't. This component controls heat distribution between hot water and heating circuits. Replacement costs typically start from £300.


When to Consider a Boiler Replacement

Modern boilers typically last 10-15 years with proper maintenance. If your boiler is approaching this age and requiring frequent repairs, replacement might be more cost-effective. Consider these factors:


  • Age of your current system

  • Frequency of repairs

  • Rising energy bills

  • Inconsistent heating performance


Professional Help from QF Maintenance


Our Gas Safe registered engineers can:

  • Diagnose complex heating issues

  • Perform annual boiler services

  • Advise on repair vs. replacement

  • Provide emergency heating services

  • Install new, efficient boiler systems


Contact QF Maintenance Today


Don't let heating problems disrupt your comfort. Our experienced team is ready to help diagnose and resolve your boiler issues quickly and efficiently. Contact us today for:


  • Free consultation

  • No-obligation quotes

  • Expert advice

  • Emergency services

  • Professional maintenance


Call 020 8050 4507 or visit our website to schedule an appointment with our certified heating engineers.

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