Common problems guide

The most common Alpha Intec 28GS problems

The faults most likely to send a Alpha Intec 28GS into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

This model is discontinued. Parts can be harder to source and expensive. If repair costs are mounting, a new A-rated boiler may be the smarter choice.
88 documented codes
6 most common
5 DIY-safe checks
1 engineer needed

The 6 most common faults

01
E04 High DIY-safe

Your boiler is struggling because it cannot detect enough water flowing through its internal system, which prevents it from safely heating your home.

What to try first

Check your boiler's pressure gauge on the front panel; it should be between 1.0 and 1.5 barIf the pressure is below 1.0 bar, locate the filling loop hose underneath the boilerOpen the valves on the filling loop to allow cold mains water in until the needle reaches 1.5 bar, then securely close the valves

Est. cost
£80-150
Parts
Central heating pump, Flow switch, System pressure sensor
Full guide for E04
02
E10 High DIY-safe

Your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.

What to try first

Locate the external filling loop, which is a silver braided flexible hose connected to two valves under the boiler.Open the valves slowly to allow mains cold water into the system until the pressure gauge on the front panel reads between 1.0 and 1.5 bar.Close both valves tightly to prevent over-pressurisation.

Est. cost
£0-£100
Parts
Filling loop, Pressure relief valve, Pressure sensor
Full guide for E10
03
E31 High DIY-safe

Your boiler has lost its connection to the digital wall thermostat, meaning it no longer knows when to turn the heating on or off.

What to try first

Switch the boiler off at the fused spur or mains power supply.Wait for 60 seconds to allow the internal electronics to fully reset.Turn the power back on and check if the remote control screen has reconnected to the boiler.

Est. cost
£90-180
Parts
Remote thermostat unit, PCB (Printed Circuit Board), Communication cable
Full guide for E31
04
10 High DIY-safe

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

What to try first

Locate the external filling loop, usually two silver flexible hoses with small taps attached under the boiler.Open the taps slowly to allow water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close both taps tightly and check the boiler display to see if the fault has cleared.

Est. cost
£0-£120
Parts
Filling loop, Pressure relief valve, Pressure sensor
Full guide for 10
05
24 High DIY-safe

The boiler's control panel detects that one of the buttons is jammed, preventing it from functioning correctly.

What to try first

Switch off the boiler at the electrical fused spurGently press and release each button on the control panel to see if any feel stuck or fail to 'click'Use a dry, soft cloth or gentle air duster to remove any debris or sticky residue around the buttonsWait 5 minutes and switch the power back on to see if the error clears

Est. cost
£100-200
Parts
Control panel/PCB interface, Fascia buttons
Full guide for 24
06
E01 High Engineer

Your boiler is failing to light the flame needed to heat your water and home.

Est. cost
£120-250
Parts
Ignition electrode, Gas valve, PCB
Full guide for E01

on the Alpha Intec 28GS

Central heating pumpFlow switchSystem pressure sensorFilling loopPressure relief valvePressure sensor

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Alpha shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
See the full 88-code list for the Alpha Intec 28GS