BoilerFaultCodes DRY-FIRE
Flow & Return reversed, system not full of water, or pump fault.
Potterton Promax SL 12 Heat ErP Fault codes & diagnostics
6 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Gas 2006-present
GC Number 41-592-34
Download the Potterton Promax SL 12 Heat ErP manual
PDF
Versions & GC numbers
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 6 Unrated
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-592-34 | Promax SL 12 Heat ErP | 2006–present |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Just want the most common Potterton Promax SL 12 Heat ErP faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 6 documented codes
Tap any card for details
FAN LOCKOUT
Fan fault or fan PCB wiring fault.
IGNITION LOCKOUT
No gas at gas valve inlet, blocked flue, condensate trap blocked, damaged spark/flame probe, or burner blocked.
OVERHEAT LOCKOUT
Flow pipe stat fault, fan stat fault, faulty thermistor, or combustion chamber door seal damaged.
PCB Fault
Replace PCB.
THERMISTOR
Thermistor resistance out of range or wiring fault.
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