Alpha 04 Fault Code (E-Tec 28 and 33)

Safety disclaimer

Fault code summary

Manufacturer

Alpha

Fault code

04

Fault type

Gas valve, Electrical

Severity

high

Reset

Not specified

Applicable models

E-Tec 28, E-Tec 33

Quick answer

Gas-valve electrical connection fault.

What does this fault code mean?

Gas-valve electrical connection fault.

Common causes

• Gas-valve wiring circuit fault.
• Gas-valve lead connection fault.
• Faulty gas valve or PCB.

Symptoms

This information was not provided in the verified manufacturer source.

What can the homeowner safely check?

This information was not provided in the verified manufacturer source.

Boiler reset information

Reset information was not provided in the verified manufacturer source. Do not repeatedly reset an unresolved fault.

When should I call an engineer?

Contact a suitably qualified heating engineer when the fault persists, the boiler locks out, or the manufacturer instructions do not resolve it. For gas appliance work in the UK, use a Gas Safe registered engineer.

Engineer diagnosis

• Assess the gas-valve wiring, gas valve and PCB.

Applicable boiler models

• E-Tec 28
• E-Tec 33

Related fault codes

• 01 — E-Tec 28 and 33

  Ignition failure; flame not detected during the ignition sequence.

  Read fault code
• 02 — E-Tec 28 and 33

  Overheat boiler lockout.

  Read fault code
• 03 — E-Tec 28 and 33

  High flue temperature.

  Read fault code
• 05 — E-Tec 28 and 33

  CH flow sensor fault.

  Read fault code
• 06 — E-Tec 28 and 33

  DHW sensor fault.

  Read fault code
• 08 — E-Tec 28 and 33

  Maximum number of resets reached (five).

  Read fault code
• 10 — E-Tec 28 and 33

  Primary system pressure low.

  Read fault code
• 16 — E-Tec 28 and 33

  Fan fault.

  Read fault code

Manufacturer documentation

04 | Gas valve electrical connection fault | Gas valve wiring circuit fault detected | Gas valve lead connection fault; faulty gas valve; faulty PCB

Last verified

2026-09-12

Frequently asked questions