BoilerFaultCodesWhat the manual says
Manufacturer manualMains supply frequency incorrect - There may be a problem with your power supply.
What causes this fault?
This fault occurs when the boiler's internal computer detects that the incoming electricity from your home is not at the steady frequency it requires to operate safely. The most common reason is an issue with the local power grid or faulty electrical wiring within the property that is interfering with the power signal. In some cases, the boiler's main control board may have developed a fault, causing it to misread an otherwise healthy power supply.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Avoid the next call-out bill
A cover plan would handle faults like E35: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Related fault codes
All 29 fault codes on the C36
Seeing a different code? Every code this model can display, in one place.