Common Worcester Bosch Boiler Problems and Repairs

Even though Worcester Bosch boilers are manufactured with quality in mind, it doesn’t mean that they can’t develop faults from time to time. Living with a broken boiler can be tough, especially if it decides to pack up during autumn or winter as these are the busiest times of the year for boiler engineers. On the bright side, not all Worcester Bosch boiler faults are serious and you might find that the problem is a simple fix that you can do yourself. But when it comes to serious faults and boiler repairs that can only be fixed by removing the boiler casing, these should always be handled by a qualified heating engineer.

We’ve compiled a list of the most common Worcester Bosch faults and what you need to do next.

1. Boiler is losing pressure

This is usually down to a leak, a damaged pressure relief valve or your boiler just losing pressure after the heating has been off for quite some time.

What to do next: You can try and re-pressurise the boiler yourself if the pressure gauge is lower than 1 bar, and make sure you look at the manufacturer’s manual to find out the correct pressure level before you start. If you still have problems after re-pressurising your boiler, you’ll need to call out a professional boiler engineer.

2. Boiler is leaking water

If your boiler is leaking water it could be one of a few things, such as a loose connection or a broken part.

What to do next: As it’s unsafe for you to attempt to fix a leaking boiler, you have no other choice than to contact a qualified engineer.

3. Pilot light won’t stay on

A pilot light that keeps going out can be the result of broken thermocouple, a damaged seal or deposits that have built up in your system.

What to do next: Check if your stopcock is switched on and then try using some of your other gas appliances to see if it’s just an issue with the gas supply. If your other gas appliances also refuse to work you’ll need to get in touch with your gas supplier, but if they all seem fine then you’ll have to call an engineer for help.

4. Frozen condensate pipe

As the condensate pipe usually runs outside into a drain, it can freeze during the colder months of the year. It’s a very common problem, and you may even find that your boiler displays a fault code to alert you that you have a blocked or frozen condensate pipe.

What to do next: You might be able to thaw the condensate pipe yourself by pouring warm water onto it or by placing a tea towel soaked in warm water over the pipe. Be careful not to use hot water. If you would rather not do this yourself, simply contact a professional engineer to do it for you.

5. Boiler kettling noises

If your boiler is making banging, clanking or rumbling noises (also known as boiler kettling), you should have it looked at as soon as possible because it is telling you that something is wrong.

What to do next: Whilst you can try and bleed your radiators to remove any trapped air and build-up of limescale, it’s best to get an engineer to take a look as they’ll be able to quickly determine the exact cause and rectify the problem.

6. No heating or hot water

There are many potential reasons why your boiler is only producing either heating or hot water and not both, such as an issue with the thermostat or broken airlocks and diaphragms.

What to do next: The only thing you can do when this happens is to check the boiler pressure and the thermostat. If they appear to be correct, you must contact a trusted engineer, who will probably need to replace one of the parts to get your boiler working again.

7. The top, middle or bottom of radiators won’t heat up correctly

If the heat on your radiators is patchy or your radiators are not heating up at all, it’s highly likely that there is air trapped or a build-up of sludge in the system.

What to do next: The easiest way to get rid of trapped air is to bleed the radiators, which is something you can try to do yourself using a radiator bleed key. You’ll need the bleed key to open the bleed valve at the top of the radiators but make sure you open the valve slowly. Don’t ever open the valve fully, just a quarter or half turn should be sufficient. You’ll also need a cloth or a towel to catch any water that drips once you open the valve. When the air stops hissing out and water starts to drip, you can close the valve. If this doesn’t help your radiators to heat up correctly, get an engineer to take a look as your system may need a power flush or you might have to replace your radiators.

8. Boiler keeps turning itself off

This could be because of low boiler pressure or a blockage that is restricting the water flow. Alternatively, it could be that the pump is faulty or there is a problem with the thermostat.What to do next: You can re-pressurise your boiler if it’s not at the correct level (check the boiler manual for this) and test out the thermostat to see if it’s working as it should be. If both the pressure and thermostat are fine or the problem persists after re-pressuring the boiler, contact an engineer for further assistance in diagnosing and fixing the fault.