Verified boiler fault code

Warmflow E11 Fault Code (Agentis Boilers (B-Series, I-Series and E-Series))

Tank limit.

Safety disclaimer

Boiler repair help from Aza & Sons Services

Fault code summary

Manufacturer: Warmflow
Fault code: E11
Fault type: Hot water, Temperature sensor, Safety lockout
Severity: high
Reset: The manual states that E11 is stored in error history for diagnosis and is not displayed on the LCD; no user reset is confirmed.
Applicable models: B21, B26, B33, I21, I26, I33, I44, I21PRO, I26PRO, I33PRO, I44PRO, I21P/PRO, I26P/PRO, I33P/PRO, I44P, I21S/PRO, I26S/PRO, I33S/PRO, I21C/PRO, I26C/PRO, I33C/PRO, E21, E26, E33, E44, E21PRO, E26PRO, E33PRO, E44PRO, E21P/PRO, E26P/PRO, E33P/PRO, E44P, E21S/PRO, E26S/PRO, E33S/PRO, E21C/PRO, E26C/PRO, E33C/PRO

Quick answer

Tank limit.

What does this fault code mean?

Tank limit.

Common causes

Displaced tank NTC temperature-sensor probe

Symptoms

E11 stored in the error history; it is not displayed on the LCD

What can the homeowner safely check?

Record any stored code and arrange qualified service; do not access the tank sensor.

Boiler reset information

The manual states that E11 is stored in error history for diagnosis and is not displayed on the LCD; no user reset is confirmed.

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

A qualified engineer should investigate the tank NTC probe and its position.

Applicable boiler models

Related fault codes

Manufacturer documentation

Warmflow Agentis Boiler Manual 6572 G

Last verified

2026-09-12

Frequently asked questions

What does Warmflow E11 mean?

Tank limit.

Can I reset a Warmflow E11 fault?

The manual states that E11 is stored in error history for diagnosis and is not displayed on the LCD; no user reset is confirmed.