Verified boiler fault code
Sime ALL 89 Fault Code (Brava Slim HE ErP)
Unstable combustion feedback-signal error.
Safety disclaimer
Fault code summary
- Manufacturer
- Sime
- Fault code
- ALL 89
- Fault type
- Combustion, Flame detection, Flue
- Severity
- high
- Reset
- The official table gives engineer checks; no repeated homeowner reset is advised.
- Applicable models
- Brava Slim HE ErP 25, Brava Slim HE ErP 30, Brava Slim HE ErP 35, Brava Slim HE ErP 40
Quick answer
Unstable combustion feedback-signal error.
What does this fault code mean?
Unstable combustion feedback-signal error.
Common causes
- Electrode issue
- Flue/outlet issue
- Air-diaphragm issue on applicable balanced-flue models
- Gas-calibration issue
Symptoms
- ALL 89 alarm displayed
What can the homeowner safely check?
- Do not touch the electrode, flue, gas valve or combustion controls; arrange qualified service.
Boiler reset information
The official table gives engineer checks; no repeated homeowner reset is advised.
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 electrode, outlets, air diaphragm where applicable and gas calibration.
Applicable boiler models
Related fault codes
- ALL 01 — Brava Slim HE ErP
Flue-gas thermostat fault.
Read fault code - ALL 02 — Brava Slim HE ErP
Low water pressure in the appliance.
Read fault code - ALL 03 — Brava Slim HE ErP
High water pressure in the heating circuit.
Read fault code - ALL 44 — Brava Slim HE ErP
No-flame gas-valve opening-time sum anomaly.
Read fault code - ALL 56 — Brava Slim HE ErP
Lock for delivery/return temperature difference above the maximum limit.
Read fault code - ALL 57 — Brava Slim HE ErP
Lock for the flow-temperature check (open-vent model).
Read fault code - ALL 62 — Brava Slim HE ErP
Self-calibration procedure required.
Read fault code - ALL 72 — Brava Slim HE ErP
Incorrect positioning of the delivery sensor.
Read fault code
Manufacturer documentation
Brava Slim HE ErP installation, use and maintenance manual (official Sime document 6322841C)Official manual fault table: | ALL | 89 | Unstable combustion feedback signal error | - Check electrode - Check outlets - Check air diaphragm (for BF models) - Check gas calibration |
Last verified
2026-09-12
Frequently asked questions
What does Sime ALL 89 mean?
Unstable combustion feedback-signal error.
Can I reset a Sime ALL 89 fault?
The official table gives engineer checks; no repeated homeowner reset is advised.