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Why your boiler is giving you hot water but no heating.
If your boiler gives hot water but no heating, don’t worry — it’s usually a quick fix. Here’s how we guide you through it.
Typical causes
Areas to check and solutions for when the boiler is only heating water.
- Review your heating controls.
It’s easy to overlook, but sometimes the thermostat is the reason your heating isn’t coming on but your hot water is working. Check that your thermostat is switched on, set above the current room temperature and fully charged if it’s battery-operated.
Ensure, you have the right boiler settings in place. Take a moment to review your heating controls and timer. A power cut, for example, could reset your schedule without you realising.
- Bleed your radiators.
If you’re getting hot water to your taps but your radiators aren’t heating up, air trapped in the system could be causing the problem. Bleeding your radiators can release this air, helping your heating system work more efficiently.
Radiators that are warm at the bottom but cold at the top are usually also a sign that bleeding is needed.
- Inspect the diverter valve.
Hot water boilers use a diverter valve to control whether hot water goes to your taps or your heating. If this valve becomes stuck or isn’t working, you might notice you have hot water but no heating.
This is not something you can fix yourself, you should contact an expert.
- Unfreeze the condensate Pipe.
During colder months, it’s not uncommon for condensate pipes to freeze, which can cause your boiler to stop working properly.
If you suspect this could be the issue, carefully thaw the pipe following the advice on how to do this in your Vaillant boiler manual. You find it on our boiler product pages.
Two ways to get instant help from Vaillant professionals.
Our trusted Vaillant Partners are heating system experts. We’ll connect you with the right one near you.
Servicing your boiler
Regular check-ups are the key to boiler longevity.
- Crucial parts check.
Count on your Vaillant-approved installer to meticulously inspect every key component, like the pressure relief valve and expansion vessel. This guarantees smooth operation, enhancing the durability and reliability of your heating system for years ahead.
- Early detection of issues.
Detecting minor issues early can save you both time and money. Routine check-ups enable your technician to pinpoint and resolve potential problems before they grow. This not only reduces repair costs but also prolongs the lifespan of your boiler.
- Blockage prevention.
Regular maintenance involves clearing sediment and debris that may build up in your system. This essential cleaning sustains peak performance and efficiency, preventing future issues that could impact your boiler's operation.
