In This Guide
What Does the Worcester E6 Error Code Mean?
The E6 error on Worcester boilers typically signals a defective or disconnected domestic hot water temperature sensor. This sensor, often an NTC (Negative Temperature Coefficient) thermistor, monitors water temperature and reports it to the boiler’s control unit. If it fails, the boiler may stop producing hot water, run water too hot or too cold, or shut down entirely and display the fault.
This error is one of several sensor-related fault codes and can appear alongside issues affecting the flow temperature sensor, flue gas thermostat, or pressure sensor. Without a working hot water sensor, the boiler can’t guarantee safe operation, so it locks out rather than risk scalding or an unregulated temperature.
Signs of a Hot Water Sensor Issue in Worcester Boilers
If your boiler is showing the E6 fault, you might also notice one or more of the following:
- Water taking longer than usual to heat up
- Inconsistent hot water temperature, running hot then cold
- No hot water at all, even while the heating still works
- The error appearing or disappearing depending on hot water demand
- The burner briefly firing then cutting out
These symptoms point to a fault in the domestic hot water system, either the sensor itself, its wiring, or a related component that shares diagnostic circuitry with it.
Common Causes of the E6 Fault
Cause
| What’s happening |
Sensor degradation | Age or limescale build-up affecting the NTC sensor’s accuracy |
Wiring fault or short circuit | A break or short in the connection between sensor and control unit |
Incorrect or faulty code plug | The control module isn’t reading a compatible configuration |
Flue gas thermostat tripping | An overheat protection response affecting sensor readings |
Related sensor fault | A fault on the heat exchanger or flow temperature sensor triggering a knock-on E6 |
Gas valve or ignition fault | A signal fault elsewhere in the system misreported as a sensor issue |
This fault is especially common in the Worcester Bosch CDI Compact, CDI Classic Combi, CDI Classic Regular, and Greenstar i System Combi ranges.
Troubleshooting the Worcester E6 Fault
If you’re comfortable with basic boiler checks, there are a few things worth trying before calling an engineer:
- Reset the boiler. Some internal faults clear after a reboot. Check your manual for the correct reset procedure for your model.
- Check hot water flow at the tap. Note whether the delay or temperature problem is constant or intermittent.
- Check the display for secondary errors. A second code alongside E6 usually points to where the fault originates.
- Don’t attempt internal testing. Sensor wiring, the gas valve, and the control module should only be handled by a Gas Safe registered engineer. Never tamper with the gas supply or modulating gas valve yourself.
If a reset doesn’t clear the fault, or it returns shortly after, the sensor itself likely needs inspecting or replacing.
How Much Does an E6 Repair Cost?
Most E6 repairs involve inspecting and, where necessary, replacing the DHW sensor, which is typically a same-day fix. 0800 Homefix charges £120 for the first hour’s labour, charged in advance, with any further repair cost confirmed before work begins. See our boiler repair rates for full pricing.
How 0800 Homefix Can Help
0800 Homefix’s Gas Safe engineers diagnose and resolve E6 faults across London and the South East, covering the sensor itself as well as related components that can trigger the same code: wiring and connections, the control module, and the flue gas thermostat. We service the full Worcester Bosch range, from the CDI Classic Regular through to the Greenstar i System.
Most E6 repairs are completed in a single visit. If the sensor needs replacing, we carry common parts on the van to avoid a second callout.
How to Prevent Worcester Hot Water Sensor Issues
Book an annual boiler service so the NTC sensor and flue gas thermostat are checked before they fail. Keep your system pressure within range, since pressure drops can affect sensor logic and trigger false readings. If you’re in a hard water area, consider a water softener, since limescale build-up on the sensor is one of the more common causes of degradation over time.
Helpful Resources
- Worcester Bosch Support: https://www.worcester-bosch.co.uk
- Gas Safe Register: https://www.gassaferegister.co.uk
- UK Boiler Safety Advice: https://www.gov.uk
Frequently Asked Questions
What does the E6 error mean on a Worcester boiler?
Can I fix the Worcester E6 error myself?
Why does the hot water go cold suddenly?
Can 0800 Homefix repair this on the same day?
Does E6 affect the heating as well as hot water?
Spotted the E6 Error on Your Boiler?
0800 Homefix’s Gas Safe engineers cover London and the South East, seven days a week, 365 days a year, with a one-hour emergency response. £120 covers the first hour’s labour, charged in advance, with any further cost confirmed before work starts.
Editorial note
This article is a general homeowner guide. All gas work should be carried out by a Gas Safe registered engineer. If you suspect a gas leak, leave the property immediately and call the National Gas Emergency Service on 0800 111 999.
Spotted Any of These Warning Signs?
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Editorial note: This article is intended as a general homeowner guide. All plumbing work on supply pipes should be carried out by a qualified, WaterSafe-registered plumber. If you suspect a gas leak, leave the property immediately and call the National Gas Emergency Service on 0800 111 999.
