Main Heating · Eco Compact Combi 25–30
321 boiler fault code
Main Eco Compact Combi models 25–30
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Renting? Report it to your landlord or housing provider first. They are responsible for gas safety and boiler repairs, and the repair should not cost you.
What 321 means
Hot water NTC fault
Safe check
Note the code shown on the display. Do not open, adjust or repeatedly reset the boiler. Contact a Gas Safe registered engineer.
When to contact an engineer
Note the code shown on the display. Do not open, adjust or repeatedly reset the boiler. 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
- Main Eco Compact Combi User Guide · §7.1.1 Table 9, p. 21
user guide
User Guide 7716571-04