Worcester Bosch F7 Fault Code (Greenstar FS CDi ErP Regular)

Safety disclaimer

Fault code summary

Manufacturer

Worcester Bosch

Fault code

F7

Fault type

Flame detection, Safety lockout

Severity

high

Reset

Not specified

Applicable models

Greenstar FS 30CDi ErP Regular, Greenstar FS 42CDi ErP Regular

Quick answer

Flame detected even though the boiler is switched off.

What does this fault code mean?

Flame detected even though the boiler is switched off.

Common causes

• Flame signal detected while the boiler is off.

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

• Investigate flame sensing and gas-valve shut-off behaviour.

Applicable boiler models

• Greenstar FS 30CDi ErP Regular
• Greenstar FS 42CDi ErP Regular

Related fault codes

• A7 — Greenstar FS CDi ErP Regular

  Hot water NTC sensor defective.

  Read fault code
• A8 — Greenstar FS CDi ErP Regular

  Break in communication to the weather compensating clip-in control or Greenstar Comfort II RF.

  Read fault code
• b1 — Greenstar FS CDi ErP Regular

  Code plug not detected.

  Read fault code
• C6 — Greenstar FS CDi ErP Regular

  Fan speed too low.

  Read fault code
• d5 — Greenstar FS CDi ErP Regular

  Condensate pump fault.

  Read fault code
• E2 — Greenstar FS CDi ErP Regular

  CH flow NTC sensor defective.

  Read fault code
• E9 — Greenstar FS CDi ErP Regular

  Safety temperature limiter in the CH flow has tripped.

  Read fault code
• EA — Greenstar FS CDi ErP Regular

  Flame not detected.

  Read fault code

Manufacturer documentation

F7 | Flame detected even though boiler switched off.

Last verified

2026-09-12

Frequently asked questions