Potterton · Assure Combi
E321 boiler fault code
Assure Combi 25/30/36
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What E321 means
Hot water temperature sensor fault
Safe check
Note the code. Do not open or adjust the boiler, or repeatedly reset it. Contact a Gas Safe registered engineer.
When to contact an engineer
Contact a Gas Safe registered engineer.
Safety notice
A boiler fault code alone is not a gas or carbon-monoxide emergency. If you smell gas, a CO alarm sounds, anyone feels unwell, or there is an unsafe flame, leave and call 0800 111 999 from outside.
Source and provenance
- Baxi Professional error-code table · Potterton Assure Combi & System (Other tab) · E321 row
professional error-code table
Official Baxi web table; revision not stated
- Potterton Assure Combi User Guide 7678847-A (22/05/2017) · Tab.9, p.21
user guide
22/05/2017 · document 7678847-A