BoilerFaultCodesPotterton 1 flash red Fault Code
Also written as 1FLASHRED — same fault.
The Potterton 1 flash red fault code means: your boiler has stopped heating because it is unable to accurately measure the temperature of the water flowing through it, likely due to a loose wire or a faulty sensor.. It appears on 1 Potterton model in our database.
Technical description: Sensor error: Bad connection to flow or return temperature sensor, Fault with flow or return temperature sensor(s), Low or no flow through boiler, Reverse flow through boiler
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like 1 flash red: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Potterton models that show the 1 flash red fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton 1 flash red fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026