Worcester Boiler Error Codes

I know, getting a Worcester boiler error code can be a pretty daunting thing, the absolute last thing you want during winter is to have your boiler break down. I understand it can be pretty stressful, but it doesn’t necessarily mean a significant expense.

A lot of error codes can simply be solved by a reset, or what you may think is an error code might not be. In this article, I’ve researched & explored errors with Worcester Bosch boilers, answering some of the most common fault questions, telling you how you can reset the boiler & providing a full breakdown of the fault codes & what the suggested action for solving them should be.

If you want to find out more, it’s a rather long article, so you can use the navigation below to quickly answer your specific query:

• Why is my Worcester Bosch boiler flashing?
• How do I fix EA error on my Worcester boiler?
• How do you reset the code on a Worcester boiler?
• What are the most common Worcester Bosch boiler faults?
• Most common Worcester Bosch boilers
• List of Worcester boiler error codes
• Other Worcester Bosch boiler errors
• Get A Boiler Repair Quote

Now let’s dig into this complete Worcester Bosch boiler error & fault code guide, and diagnose the issue with your boiler.

My Worcester boiler has a flashing blue light (How To Fix It)

You may have noticed a blue flashing light on your Worcester Bosch, this indicates that your boiler is experiencing a fault, and it can be one of 5 different things. You will need to determine what error code is being displayed whilst the light is flashing to find out exactly what it could be. Here’s a breakdown of the potential issues related to the flashing blue light:

1. Condensate pipe blockage (D5 or EA Error Code): Remember the beast from the east? That storm a few years back. This error happened all the time. All boilers have a condensate pipe and sometimes it freezes up, all you have to do is boil your kettle and pour some hot water over it to thaw the ice and unblock the pipe.
2. Flue blockage (EA Error Code): This is a common one, just check the flue for any blockages or damage. It’s the exit pipe you might find on the outside of your building. If you can’t see anything you might need to replace the flue, which means calling a boiler engineer.
3. Gas Supply Issue (EA Error Code): If there is no gas supply to the unit, this could be the cause. You should check your other gas appliances if you have any, if they aren’t working then you might have an issue with your homes gas supply, if they are, then it’s likely an issue with the gas connection to your boiler.
4. Low Pressure (CE207 Error Code): It happens, from time to time boilers do lose pressure, and it needs to be at a good level to operate. The pressure should be between 1 and 1.5 bars, so just top it up if this is the case with the fill loop.
5. Service Mode (No Error Code): The boiler could be in service mode, it might have been left this way by an engineer or the switch could have been knocked. You should be able to press (& hold on some models) the spanner button to exit this mode.

How do I fix EA error on my Worcester boiler?

The Worcester Bosch boiler EA fault code is one of the most common, if not the most common error on this model. It means that the boiler has not detected a flame when it has tried to light (start).

You should first try to reset the boiler first, hold the reset button for 5 seconds.

If the issue persists, you are unfortunately going to have to calling a boiler engineer. There’s no need to be concerned though, the EA code is a safety mechanism, your boiler or surroundings aren’t at risk of any gas leaks or major issues.

How do you reset the code on a Worcester boiler?

If a fault occurs on your boiler, the first thing you should always do is reset it. To do this you simply reset the boiler, which is fairly simple and straight forward to do, just turn the central heating temperature knob anti-clockwise until it reaches the position that reads “Reset” – hold it in this position for five to ten seconds, then go back to the original setting you had it on.

After a few seconds, your boiler should reset, and hopefully, the error code will be gone. You’ll be surprised how many errors can be fixed by simply resetting the boiler.

What are the most common Worcester Bosch boiler faults?

I will dig into each and every Worcester Bosch boiler error later, however, there are a few common error codes that come up time and time again that people regularly search for.

Here are the most common:

• EA – This means no flame has been detected on ignition, reset the boiler, if this doesn’t fix it, call a boiler engineer
• E9 – This is an issue with the safety sensor, it’s either at a too high temperature or short circuited. This could be the boiler overheating.
• A21 – This is actually an error on a programmable thermostat
  & it indicates no RF signal, the signal needs to improve, try moving the thermostat closer to the boiler.
• EA 227 – This error is due to the boiler trying to ignite four times and failing to do so. It will attempt this again, but if no flame is detected you’ll be locked out, and you have to call a boiler engineer
• EH – Or EH 258 is the heat control module or control box being defective and needs to be checked

Most common Worcester Bosch boilers

There are several boilers, and in the next error code list I will cover the error codes from them all. However for reference here are some of the most common boilers and their series:

Worcester Bosch Boiler Series

1. Worcester Bosch I Series
2. Worcester Bosch Life
3. Worcester Bosch Si
4. Wocester Bosch CDi
5. Worcester Bosch Heatslave

Most Common Worcester Bosch Boilers

1. Worcester Bosch 30i
2. Worcester Bosch 28i Junior
3. Worcester Bosch 30CDi
4. Worcester Bosch Greenstar 8000 Life
5. Worcester Bosch 30si

List of Worcester boiler error codes

Now the bit you’ve been waiting for. The comprehensive list of Worcester boiler error codes. It’s a rather long list & certain codes apply to certain kinds of boiler, so I’ve included a quick search function, where you can simply type in your error code and you’ll be able to locate yours.

Error Code	Description of Fault	Potential Solution
226	In the block error history menu the service tool has been connected	You shouldn't be seeing this unless your boiler is being serviced
235	You need to install the latest software in the Heat Control Module.	You will need to call a boiler engineer
328	The mains voltage has an internal error & the frequency can be quite inconsistent	You will need to call a boiler engineer
356	The mains voltage is low, there could be something wrong with the way in which the boiler is receiving voltage	This may require an electrician if it's an issue with your house mains
360	The control box & heat control module aren't meant to be together, it's been configured incorrect	Get in touch with whomever did the installation for you
1010 O	The EMS bus is damaged, or disconnected.	You will need to call a boiler engineer
1017 W	The water pressure is too low	Top up the water pressure on your boiler manually. If the issue persists then this will be an issue with the pressure sensor and you may need to You will need to call a boiler engineer
1021 B	The sensor for the hot water temperature is defective	You will need to call a boiler engineer
1022 B	The temperature for the hot water storage is defective	It can be as simple as it being out of place, but we don't advise opening the boiler, you will need to call a boiler engineer
1037 W	The sensor for the outside temperature is defective	Check if it's connected, if you're not confident, call a boiler engineer
1065 B	The pressure sensor is broken	You will need to call a boiler engineer
1068 W	The sensor for the outside temperature is defective	Check if it's connected, if you're not confident, call a boiler engineer
1073 W	The flow temperature sensor has short circuited and needs replacing	You will need to call a boiler engineer
1074 W	The flow temperature sensor isn't getting a signal	You will need to call a boiler engineer
1075 W	The temperature sensor at the heating block has short circuited	You will need to call a boiler engineer
1076 W	No signal from the temperature sensor	You will need to call a boiler engineer
200 O	Heating mode demanded from the boiler	No action
201 O	Hot water mode demanded from the boiler	No action
202 O	Anti-cycle mode activated	No action
203 O	Standby mode	No action
204 O	Water temperature is higher than the set temperature	Leave the boiler - this could produce an error code later
208 O	Chimney sweep required	Self explanatory!
224 V	The limiter for the safety temperature has tripped	Top up the boiler pressure - it may also need resetting
227 V	After igniting there is no flame signal	Try reset the boiler, but if there's no luck you will need to call a boiler engineer
228 V	There is a flame signal, but no actual flame present	You will need to call a boiler engineer
2920 V	Flame monitoring error	Try resetting the boiler
2924 V	The gas modulating valve isn't getting any feedback	The valve is defective you will need to call a boiler engineer
2925 V	The gas modulating valve is getting a feedback that is too low	Reset the boiler, if the problem persists you will need to call a boiler engineer
2927 B	During the operation of the burner the flame valve failed	Check the gas supply to your home
2946 V	The code plug is incorrect & needs replacing	You will need to call a boiler engineer
2948 B	This is no flame signal and can be due to the setting of the CO2 valve	Reset the boiler
2950 B	No flame signal, the gas / air ratio needs correctly setting up	You will need to call a boiler engineer
2963 B	The signal for the heat exchange sensor and flow sensor is out of range	You will need to call a boiler engineer
2964 B	The heat exchanger flow rate is too low	You will need to call a boiler engineer
2965 B	Too high flow temperature	Turn the boiler off & leave it to cool down, turn back on again
2966 B	In the heat exchanger the flow temperature has risen too rapidly	Reset the boiler
2967 B	The differential between the flow and heat exchange sensor is too large	You will need to call a boiler engineer
2970 B	The pressure has dropped rapidly in the heating system	You will need to call a boiler engineer
2971 B	The pressure of the system is too low	Top up the system pressure manually
305 0	Hot water anti-cycle mode activated	No action
306 0	After closing the fuel supply it is still getting a flame signal	You will need to call a boiler engineer
360 V	The code plug is incompatible	Contact whomever installed the boiler
815 W/B	The sensor for the low loss header temperature is faulty	You will need to call a boiler engineer
9U 233	The heating control module or control box is loose	You will need to call a boiler engineer
A1	In the block error history menu the service tool has been connected	You shouldn't be seeing this unless your boiler is being serviced
A1 281	Running dry or pump stock	You will need to call a boiler engineer
A5	During a lockout the power has been interrupted	Reset the boiler
A7	The fan doesn't run when starting the boiler	Defective fan, you will need to call a boiler engineer
A8	The speed of the fan is too high	Reset the boiler
A8 362	Mains voltage is too low	This may require an electrician if it's an issue with your house mains
B1	The fan speed is too low	Reset the boiler
B2 Through to B7	During the operation the fan has stopped running	Reset the boiler, if the fault continues you will need to call a boiler engineer
B7 257	The heating control model or control box is defective	You will need to call a boiler engineer
C1 264	During the operation the fan has stopped running	Reset the boiler, if the fault continues you will need to call a boiler engineer
C4 237	The heating control model or control box is defective	You will need to call a boiler engineer
C4 273	The fan has been in continuous operation for the last 24 hours	It will shut off to protect the fan
C6	The fan has been in continuous operation for the last 24 hours	It will shut off to protect the fan
C6 215	The speed of the fan is too high	Reset the boiler
C7 214	The fan doesn't run when starting the boiler	Defective fan, you will need to call a boiler engineer
C7 216	The fan speed is too low	Reset the boiler
C7 217	During the operation the fan has stopped running	Reset the boiler, if the fault continues you will need to call a boiler engineer
CC 800	Outdoor sensor defect available	No action
D3	The flow temperature sensor has shorted	You will need to call a boiler engineer
D4 341	Temperature rising too fast of the primary flow	Reset the boiler
D5	Disconnected flow temperature sensor	You will need to call a boiler engineer
D6	95 degrees exceeded on primary flow temperature	Reset the boiler
E2	Disconnected flow temperature sensor	You will need to call a boiler engineer
E2 222	The flow temperature sensor has shorted	You will need to call a boiler engineer
E2 233	Disconnected flow temperature sensor	You will need to call a boiler engineer
E2 350	The flow temperature sensor has shorted	You will need to call a boiler engineer
E2 351	Disconnected flow temperature sensor	You will need to call a boiler engineer
E9	After the gas valve has closed ionisation has been detected	You will need to call a boiler engineer
E9 224	Thermostat high limit has been activated	Reset the boiler
E9 276	95 degrees exceeded on primary flow temperature	Reset the boiler
EA	The flow temperature sensor has shorted	You will need to call a boiler engineer
EA 227	After ignition there is no ionisation detected	You will need to call a boiler engineer
EA 229	Signal loss for the detection of ionisation	Reset the boiler
EA 261	Heat control module might have an issue	Reset the boiler, if the issue persists you will need to call a boiler engineer
EH 258	Heat control module or control box has an issue	You will need to call a boiler engineer
F0	After ignition there is no ionisation detected	You will need to call a boiler engineer
F0 238	Control box error, or an issue with the gas valve	You will need to call a boiler engineer
F0 239 through to FO 290	Control box or heating control module is defective	You will need to call a boiler engineer
F1	Before the burner starts, ionisation current has been detected	Reset the boiler
F1 259 & F1 263	Control box or heating control module is defective	You will need to call a boiler engineer
F7	During operation there has been a loss of ionisation signal	Reset the boiler
F7 228	Before the burner starts, ionisation current has been detected	Reset the boiler
FA	Heat control module is potentially defective	Reset the boiler, if the issue persists you will need to call a boiler engineer
FA 306	After the gas valve has closed ionisation has been detected	You will need to call a boiler engineer
FD	Control box or heating control module is defective	You will need to call a boiler engineer
FD 231	During lockout the power has been interrupted	Reset the boiler
Flashing but mostly off	An ignition lockout	Reset the boiler
Flashing but mostly on	Heat exchanger or flue overheated	Reset the boiler
Flashing fast	Code plug or volatile lockout sensor fan	You will need to call a boiler engineer
Light off	Control board has no power	Check the power to the boiler is on, if it is, you will need to call a boiler engineer
Light on	The appliance is on	No action
Pulsing 2x	Service mode switch	Make sure the service mode switch is in the minimum position
Pulsing 5x	Service mode switch	Make sure the service mode switch is in the maximum position

Other Worcester Bosch boiler errors

Got an error with your Worcester Bosch boiler but it doesn’t quite equal up to or isn’t displaying an error code? Well, it could still be one of a few things, which I’ve touched on below:

Locking error
If there is a flashing warning triangle and a code to go with it, it means your boiler is locked out. You should be able to solve this by simply resetting the boiler, as this should clear the fault.

Blocking error
No fault code displayed but the boiler isn’t operating? The code will actually be in the info menu, which you can get to by using the return or spanner button. Sometimes these codes will clear by themself as they often have a pre-defined duration.

Maintenance Codes
These are situations that need attention but aren’t necessarily errors, and they will show up as HH codes. H11 means there’s a defect with the hot water sensor, but your boiler will still deliver the hot water but have less control over it & H13 means it requires a service, and the service interval is set from 0 to 72 (in months) you can find this in the settings and changing it to 0 will remove the fault, although it might be time for a service.

Get a Boiler Repair Quote

Have you read about your specific fault code and unfortunately found that you might need to call a boiler engineer to rectify it? Well, although there is, of course, going to be an expense to doing so, you can use the below quote form to help you achieve the best possible price. We will do all the leg work for you, comparing local boiler engineers to find you the lowest price possible for the job.

Let us find you the best price using the form below: