Potterton Pressure Switch Assembly Honeywell C4065A1007 642218

The Potterton 642218 is an air pressure switch assembly used on Potterton Lynx 2 appliances. It monitors the pressure developed by the fan and signals the control board that air movement is present, allowing the appliance to proceed through its ignition sequence. The original switch is obsolete, and the item supplied is a Honeywell air pressure switch with the same pressure setting, fitted with a bracket in a different orientation.

• The appliance locks out or fails to reach ignition, with the fan running normally
• Repeated lockouts shortly after the fan starts, clearing on reset and returning
• Intermittent operation where the appliance runs on some attempts and not others
• Fault codes or diagnostic indications relating to air pressure or fan proving
• Visible damage, contamination or a blocked pressure sensing tube at the switch

• Confirm the GC number on the appliance data badge matches 47-590-09 or 47-590-08 before ordering
• The original Potterton switch is obsolete; the supplied Honeywell unit has the same pressure setting but a different bracket orientation, so compare the bracket against the photograph before fitting
• Check the pressure sensing tube and its connections as part of the diagnosis, as blockages can produce the same symptoms as a failed switch
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.