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F17 FAULT CODE
Saunier Duval

Low Mains Voltage

Medium Severity Engineer Required

The mains power supply voltage has dropped below 170V — too low for safe operation.

Step-by-Step Fix Guide

  1. Step 1

    Check with an electrician that the mains supply voltage is correct

  2. Step 2 Engineer only

    If mains is correct, call a Gas Safe engineer

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.

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