Verified boiler fault code
Sime ALL 84 Fault Code (Brava Slim HE ErP)
Reduced flow rate, presumed low pressure on the mains gas supply.
Safety disclaimer
Fault code summary
- Manufacturer
- Sime
- Fault code
- ALL 84
- Fault type
- Gas supply, Ignition
- Severity
- high
- Reset
- The official solution is an engineer gas-flow check; no user reset is confirmed.
- Applicable models
- Brava Slim HE ErP 25, Brava Slim HE ErP 30, Brava Slim HE ErP 35, Brava Slim HE ErP 40
Quick answer
Reduced flow rate, presumed low pressure on the mains gas supply.
What does this fault code mean?
Reduced flow rate, presumed low pressure on the mains gas supply.
Common causes
- Reduced gas flow rate
- Presumed low mains-gas pressure
Symptoms
- ALL 84 alarm displayed
What can the homeowner safely check?
- Do not alter the gas supply or appliance settings; record the alarm and contact a qualified engineer.
Boiler reset information
The official solution is an engineer gas-flow check; 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 gas flow and inlet pressure using the manufacturer procedure.
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 | 84 | Flow rate reduced for (presumed) low pressure on mains gas | - Check gas flow rate |
Last verified
2026-09-12
Frequently asked questions
What does Sime ALL 84 mean?
Reduced flow rate, presumed low pressure on the mains gas supply.
Can I reset a Sime ALL 84 fault?
The official solution is an engineer gas-flow check; no user reset is confirmed.