Broag Air Pressure Differential Switch 605.99772

The air pressure differential switch is a control component used on Broag Commercial gas boilers. It monitors the pressure difference across the combustion air path and signals the appliance's control system accordingly. This unit carries the Huba reference 605.99772 and the Broag spare part number S100613.

• The boiler fails to fire or repeatedly goes to lockout despite the fan running.
• Ignition is intermittent, with the appliance starting only on some attempts.
• The boiler shuts down shortly after firing and will not complete a run cycle.
• Fault indication points to an air pressure or differential pressure fault.
• The switch shows physical damage, contamination at its sensing ports, or perished tubing connections.

• Confirm your appliance model against the fitment list above.
• Check the reference printed on the existing switch to confirm it matches 605.99772.
• Inspect the sensing tubes and connections, as blockages or leaks can mimic a failed switch.
• Verify the appliance is a commercial Broag unit, as this control is not listed for domestic models.