What does the Main 27 fault code mean?

Your boiler is struggling to circulate water, either because there isn't enough water inside the system or because the internal pump has failed.

How much does it cost to fix Main error code 27?

Typical repair cost for the Main 27 fault is £120-300 including labour.

Check your boiler pressure gauge; if it is below 1 bar, use the filling loop to top the system up to between 1 and 1.5 bar.

Manufacturer manual

Fault on Pump or Low System Pressure

From this model's manual

Verified against the Main Eco installation & service manual, page 7.

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Boiler cover options

A cover plan would handle faults like 27: no call-out fees, no surprise bills.

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Six most common causes of dropping pressure.

Each noise points to a different fault.

7 signs repair isn't worth it anymore.