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2024 Firebird Boiler Error & Fault Codes


Firebird boiler error codes are used to indicate an error condition that has occurred within the boiler. This could be either be general or a fault code that indicates a more specific problem. Error Codes will normally remain on the display for thirty seconds and then clear (though when in the diagnostic mode, the error codes will remain on display if they were showing before entering diagnostic mode).

We've compiled a list of possible fault codes and their diagnostics so you can see what is currently wrong with your Firebird boiler.

Complete list of Firebird boiler fault codes

Fault Code Possible Cause
E1Control thermistor fault
E2Flue thermistor fault
E3Flue thermistor fault
E5Burner fault (possibly burner lockout)
Thermostat at a high limit (cuts off)Reset boiler

E1, E2, E3, E5 - No central heating

If your central heating isn't working then the most common cause is low boiler pressure. Low pressure can be due to a number of reasons, but it's usually pretty simple to diagnose the cause. It's also worth checking whether your radiators need to be bled (by checking the temperature of the bottom of the radiator) and also whether your thermostats are both turned on and functioning correctly. If all these seem to be operating correctly then it's time to speak to the professionals.

E5 - Low boiler pressure

If your central heating boiler has a pressure gauge, you will know if your heating system is low on pressure. A lower pressure can be an indication that there is an issue that needs to be addressed. Pressure is an important thing when it comes to boiler operation – if you have too much the unit will stop heating and a pressure release value will trip. If you have too little the system won’t work correctly. Generally, the boiler’s operating pressure should be between 1 bar (14.5psi) and 4 bars (60psi).

E5 - Boiler leaking

Leaking boilers are usually found during annual boiler maintenance, but they can also break down at any time. It is crucial to contact a professional after noticing a leak, otherwise your boiler may fail. An aging boiler is likely to develop a leak, but detecting the source of the leak should be done early on by a professional to ensure its safe operation. Leaks usually mean that an internal part, like a seal or valve has broken. If that happens, you may end up with corrosion or short circuits in your boiler.

How to fix a leaking boiler

There might be situations where the boiler is leaking water, but the gas itself isn’t leaking. In these cases, you should shut off the mains water supply to prevent the leak from worsening and contact a Gas Safe registered engineer.

E5 - Boiler making noises

Kettling can be caused by a build-up of limescale or sludge in the heat exchanger. It normally occurs in old boilers that are not able to heat water any more effectively, as they are losing their efficiency with age. It generates a distinctive whistling noise as the flow is restricted, causing the water to boil then steam within the heat exchanger. This is inappropriate, and can cause local flooding and damage to your heating system.

Fix strange noises

In order to keep your heating system running effectively, you should allow a Gas Safe registered engineer to powerflush the heating system. A magnetic filter could also be fitted to the heating system which will capture any dirt before it has chance to create problems.Once the powerflush has been carried out and a magnetic filter has been fitted, it would be worth running a check to see if these interventions have led to any improvement in boiler performance.

E1, E2, E3, E5 - Radiators not heating up

If you're not getting enough heat from your radiators, it could be because of sludge or air-buildup in the system. You may have to bleed them or have them professionally cleaned/flushed.

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