Turn off the gas supply
Switch off the appliance
Allow the system to cool completely
Locate the gas filter
Close any upstream and downstream valves if present
Relieve pressure in the line if required by the system
Remove the filter housing or cover
Take out the old filter element
Inspect the housing, seals, and O-rings
Replace damaged seals or O-rings
Install the new filter element in the correct orientation
Reassemble the housing or cover
Tighten all fittings to the specified torque
Open the gas supply slowly
Check for leaks at all connections
Test the appliance operation
Dispose of the old filter properly
Contact a qualified technician if you are unsure or if leaks are detected