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.