Ideal F7 Fault Code (Logic Code Combi ESP1)

Safety disclaimer

Fault code summary

Manufacturer

Ideal

Fault code

F7

Fault type

Electrical

Severity

Not specified

Reset

Not specified

Applicable models

Logic Code Combi ESP1 26, Logic Code Combi ESP1 33, Logic Code Combi ESP1 38

Quick answer

Low mains voltage.

What does this fault code mean?

Low mains voltage.

Common causes

• Mains supply voltage is low.

Symptoms

• The boiler displays F7.

What can the homeowner safely check?

• Contact a qualified electrician or electricity provider as Ideal recommends; do not open the boiler.

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

• Check the electrical supply and appliance electrical circuit.

Applicable boiler models

• Logic Code Combi ESP1 26
• Logic Code Combi ESP1 33
• Logic Code Combi ESP1 38

Related fault codes

• F1 — Logic Code Combi ESP1

  Low water pressure.

  Read fault code
• F3 — Logic Code Combi ESP1

  Fan fault.

  Read fault code

Manufacturer documentation

F7 - Low Mains Voltage — contact either a qualified electrician or your electricity provider.

Last verified

2026-09-12

Frequently asked questions