Blog>Expert Advice>Worcester Bosch boiler problems: your ultimate troubleshooting guide
Last updated: 15 October 2024
Worcester Bosch boiler problems: your ultimate troubleshooting guide
Having problems with your Worcester Bosch boiler? Read our Worcester boiler troubleshooting guide, for some of the most common faults, solutions and when to call in the experts.
As a homeowner, a broken Worcester Bosch boiler can be a real headache, especially in the winter. Cold rooms and freezing showers are the last thing you need when the temperature plummets!
Luckily some common Worcester Bosch boiler problems can be fixed easily without the need for an expert. But if a professional is needed, then we're here for you.
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Our helpful troubleshooting guide explains some of the most common Worcester boiler problems and solutions. So let's help you get everything back to normal as quickly as possible.
Worcester boiler problems
Got an issue with your boiler? From leaking water to heating on the blink, the chances are you’re dealing with one of these common faults on Worcester boilers.
Knowing what to do at the first signs of trouble could save you hefty repair bills further down the line. Here are some possible Worcester Bosch boiler problems and solutions.
Worcester boiler leaking water underneath
If your Worcester boiler is leaking water underneath, it will usually result in low pressure and your boiler locking out. The error code displayed is likely to be EA338 or sometimes A281.
There are several reasons why your boiler is leaking, but not all of them are serious. Here's everything you need to know if your boiler is leaking:
Why is my boiler leaking water?
It doesn't matter whether your boiler is leaking gas or water, a boiler leak should not be treated lightly. Whilst most faults are repairable, for safety and legal reasons you should not attempt to repair a boiler unless you are sufficiently qualified.
However, a leak can be difficult to diagnose, and even more difficult to repair, so we recommend hiring a registered Gas Safe heating engineer to investigate the issue.
Possible reasons why your boiler is leaking water include:
1. Water pressure too high
A small amount of water is nothing to worry about, but a large leak could mean there is too much water pressure inside the system.
If you're experiencing large leaks from your boiler, check your boiler’s pressure gauge. Note if the needle is pointing to green or red, if it's red, you will need to bleed your boiler. You can get rid of excess water yourself using the release valve - most boilers will have one.
2. Broken seals
With a new boiler, the joints where the pipes lead to the boiler could be damaged or incorrectly installed. Seals inside your boiler can also decay over time, especially if your boiler pressure is too high.
We don't recommend opening the boiler yourself. The pipes will be extremely hot so do not touch anything under the boiler cover. Instead, consult a Gas Safe Engineer.
3. Damaged heat exchanger
Leaking water can also be caused by more severe issues, such as corrosion to the heat exchanger.
The heat exchanger is where your boiler warms up cold water. The pipes experience frequent temperature exchanges, contracting and expanding, causing the metal to crack.
Heat exchangers are the most expensive component within a boiler, and tend to be the first component to malfunction in cheaper, low-cost systems. A damaged heat exchanger will most likely mean you need a new boiler.
Find a local expert
Generally, it’s best to leave leaking boiler repairs to a professional. If you try to fix your leaking boiler and you do so incorrectly, it could be dangerous and lead to even more expensive boiler repair costs down the line.
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Worcester boiler low pressure
Over time, it's quite normal for Worcester boilers to gradually lose some pressure and need topping up. You can check low boiler pressure by checking the pressure gauge on the boiler:
When the system is cool, the pressure gauge on a Worcester boiler should be between 1 – 1.5 bar (in the green section)
If the pressure is low, the needle will be below the green region
Check the boiler manual to see if you can re-pressurise the system yourself
Head to our guide on what to do when your boiler loses pressure for more advice
However, if your boiler's pressure continually keeps dropping and is low, it is likely caused by a leak somewhere in the system.
Commonly, this is due to holes around the bends of pipes, such as failed joints and seals.
Get in touch with a heating engineer in your area who can help diagnose and fix the problem.
Worcester boiler heating not working
If your Worcester Bosch boiler isn't heating and your radiators feel cold it could be caused by excess air or sludge trapped inside the system.
Excess air
If the cold patch is at the top of the radiator, it's probably trapped air, so you'll need to bleed it with a radiator key. Bleeding a radiator is a straightforward task and won’t take long.
Even if the cold patch is at the bottom of the radiator, it’s still worth trying to ‘bleed’ the system. If you don’t notice any trapped air escaping the system, then it’s probably time to bring in an expert.
How to bleed a radiator in 6 easy steps
Learn how to bleed a radiator with our comprehensive guide. We have everything you need to know about performing this small yet helpful task.
Trapped sludge
Often, build-ups of sludge will need to be cleaned out with a power flush by a boiler engineer. Find out how much a power flush will set you back in our cost guide.
Faulty valve
A faulty diverter valve is another common reason why your boiler heating isn't working and stopping hot water from reaching the radiators. Call a Gas Safe engineer who can repair or replace the valve.
Other reasons for your Worcester boiler heating not working include:
Not enough gas supply
Faulty ignition
Thermostat set too low
Incorrect boiler settings or boiler mode
Blocked or frozen condensate pipe
Contact or pay a trade through Checkatrade and you’re covered by our 12-month guarantee of up to £1,000*
Worcester Bosch wireless thermostat problems
Although Worcester Bosch wireless thermostats are smart, energy-efficient, and reduce heating bills, sometimes things do go wrong.
You're likely getting an A21 error code indicating your Worcester Bosch boiler and wireless thermostat are no longer communicating effectively.
Try these steps before contacting an expert to repair a thermostat for you:
Check the batteries and power supply: Replace batteries if necessary and check all devices are powered up
Reset devices: Reset the thermostat and the boiler to clear any temporary communication issues
Check the range and interference: Ensure no range issues or interferences are blocking the signal
Re-pair devices: Follow the manufacturer's instructions to re-pair the thermostat with the boiler
If you're still having problems, contact a professional to diagnose and repair the issue.
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Common faults on Worcester boilers
Other common faults on Worcester boilers include:
Banging noises
Boiler overheating
Boiler turns itself off
Boiler lockout
No power
To help you pinpoint the cause of the faults, Worcester Bosch fault/error codes begin with the letters EA and will be displayed on the boiler’s digital interface.
You can see what the code means by looking it up in your Worcester Bosch boiler user manual.
If you can't get to the bottom of the problem, it's best to call in the experts. You're probably wondering how much you need to budget for repairs, so take a look at our Worcester Bosh repair cost guide here.
Find a Gas Safe registered engineer near you
Working with gas can be dangerous, which is why only Gas Safe registered engineers are permitted to work on gas boilers. Search your postcode, below, to find approved engineers in your local area.
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FAQs
What is the average life of a Worcester Bosch boiler?
The average life of a boiler is usually between 10-15 years. However, this depends on many factors including use, maintenance, type of boiler, and installation.
Getting your boiler annually checked over or serviced by a qualified engineer is a great way to potentially extend the life of your Worcester Bosch boiler. It will also help identify and fix any faults before they become bigger problems. Find out how much a Worcester Bosch combi boiler service costs.
Why is my Worcester heating not working?
There are a number of reasons why this may have happened. For example, the boiler pressure might be too low, you might have a blocked flue or there may be an issue with the condensate pipe.
It's best to get in touch with qualified heating engineers who can identify and resolve the problem and get your heating back up and running.
What number should my Worcester Bosch boiler be on?
On Worcester Bosch boilers, both the central heating and hot water temperatures are controlled using dials numbered 1 to 6.
During the winter, the ideal central heating temperature setting should be 18-21°C, so set the heating dial to setting 4 or 5. For hot water, a Worcester Bosch boiler set at 55–60°C is sufficient for most UK homeowners, so set the hot water dial to setting 3.
Are Worcester Bosch boilers worth it?
Probably the most well-known boiler brand, Worcester Bosch was founded in 1962. It is a reputable British boiler brand that has built a very good reputation for providing good quality, energy-efficient boilers.
How long does it take to fit a Worcester Bosch boiler?
On average, it takes around 1 - 3 days to fit a Worcester Bosch boiler. Once your heating engineer has assessed your particular project, you should be provided with a more accurate timeframe.
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