F34
FAULT CODE
Ferroli
Low Supply Voltage
Medium Severity
Engineer Required
On Ferroli boilers, F34 indicates the mains supply voltage has dropped below 170V — too low for safe operation.
Step-by-Step Fix Guide
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Step 1
Check with an electrician that the mains supply is correct (230V)
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Step 2 Engineer only
If voltage is correct, call a Gas Safe engineer as the PCB may be faulty
Gas Safe Reminder
Work on gas appliances must be carried out by a Gas Safe registered engineer. The steps above cover safe checks a homeowner can perform - any internal component replacement requires a qualified professional. If in doubt, always call an engineer.