Common Alpha Boiler Error Codes

Understanding Alpha boiler fault and error codes

Alpha boilers display error codes to help identify problems such as pressure loss, ignition failure, or sensor faults.

Each code points to a specific issue within the system.

While some faults can be safely checked at home, others require professional repair.

If you are unsure, always switch off your boiler and contact a Gas Safe engineer.

Most common Alpha boiler error codes explained

Alpha E10 fault code - low water pressure or circulation issue

The E10 error is one of the most frequent Alpha boiler problems.

It usually means the system pressure has dropped below the correct level.

When cold, your pressure gauge should read between 1 and 1.5 bar.

If it is below this, top it up using the filling loop beneath your boiler.

If the pressure keeps dropping, there may be a hidden leak or a faulty expansion vessel.

Fix: Repressurise using the filling loop.
Repairable: Yes.
Call an engineer if: Pressure continues to fall after topping up.

Alpha E01 fault code - ignition failure

The E01 code means the boiler failed to ignite.

This can be caused by a gas supply problem, a faulty ignition lead, or a sensor issue.

Sometimes, switching the boiler off and back on will clear a one-off fault.

If the code returns, do not keep resetting the boiler.

Fix: Check your gas supply and ensure the meter has credit if applicable.
Repairable: Yes, if due to gas or ignition issues.
Call an engineer if: The fault reappears after resetting.

Alpha E37 fault code - pressure sensor fault

The E37 code means the boiler cannot read the correct system pressure.

The sensor may be dirty, faulty, or disconnected.

Incorrect readings can trigger safety shutdowns.

Repressurising the system may help, but if the issue continues, the sensor may need replacing.

Fix: Check the gauge and repressurise if required.
Repairable: Yes.
Call an engineer if: The fault persists after topping up.

Alpha E43 fault code - communication error

The E43 code appears when the control board cannot communicate with other components.

This is usually due to a wiring or circuit board fault.

It requires professional testing to confirm the cause.

Fix: Try one restart only.
Repairable: Yes, by an engineer.
Call an engineer if: The error remains after a restart.

Alpha E08 error code - pump or circulation fault

This fault occurs when water cannot circulate properly.

You may hear gurgling noises or find radiators staying cold.

A seized pump or trapped air in the system are common causes.

Fix: Bleed radiators to release trapped air.
Repairable: Yes.
Call an engineer if: The issue continues after bleeding.

Alpha A and B lights flashing - boiler lockout

When both lights flash, your boiler has locked out for safety.

This often follows a failed ignition or overheating event.

Fix: Turn the boiler off, wait a few minutes, then press the reset button once.
Repairable: Yes, if temporary.
Call an engineer if: Lockouts happen repeatedly.

Other Alpha boiler fault codes

Here are some other error codes you might see on different Alpha models such as Intec, E-Tec, or CD18R.

If your Alpha boiler model shows a slightly different code pattern, check your manual for the specific meaning.

The core issues remain similar across all models.

How to reset an Alpha boiler safely

Many Alpha boilers have a reset button on the control panel.

You can try this once if the code indicates a temporary problem.

1. Turn the boiler off and wait five minutes.

2. Press and hold the reset button for five seconds.

3. Wait for the display to return to normal and the boiler to relight.
   

If the same fault returns, do not reset again.
Call a Gas Safe engineer to find and fix the cause.

When to call a Gas Safe engineer

Contact a professional if:

• The same code appears more than once
  

• The boiler loses pressure repeatedly
  

• You hear unusual noises
  

• More than one error code shows at the same time
  

An engineer will test sensors, inspect internal parts, and confirm whether anything needs replacing.

This ensures your boiler operates safely and efficiently.

Preventing future Alpha boiler faults

• Keep boiler pressure between 1 and 1.5 bar - check the gauge monthly and top up if needed.

• Book annual servicing - a Gas Safe engineer will clean, test, and adjust key parts to prevent breakdowns.

• Use inhibitor fluid and filters - these prevent sludge from damaging your boiler and radiators. Bleed radiators before winter - this improves circulation and heating performance.

• Watch for early warning signs - such as cold spots, dripping valves, or changes in boiler pressure.

Before you call for help

Check that:

• Power, gas, and water are switched on
  

• The thermostat is set correctly
  

• Radiator valves are open
  

• You have noted the error code for the engineer
  

Doing these quick checks can save time and help your engineer diagnose the issue faster.

Keeping your Alpha boiler reliable

Most Alpha boiler faults, such as E10, E01, or E37, are simple to identify once you know what the code means.

Topping up pressure or bleeding radiators may fix small issues, but repeated errors mean it is time to call a Gas Safe engineer.

With annual servicing and proper care, your Alpha boiler will stay efficient, safe, and reliable all year round.

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