F5
FAULT CODE
Viessmann
Gas Pressure Switch / No Gas Pressure
High Severity
Engineer Required
The gas pressure switch is showing no gas pressure, or there is an electrical connection fault at the pressure switch. Could mean the gas shut-off valve is closed.
Step-by-Step Fix Guide
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Step 1
Check the gas isolation valve under the boiler is fully open (handle pointing along the pipe)
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Step 2
Check other gas appliances work
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Step 3 Engineer only
If gas supply is on but F5 persists, call a Gas Safe engineer to test the gas pressure switch and supply pressure
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.