Broag Air Pressure Differential Switch S45772

The air pressure differential switch is a Broag component listed for the Broag Commercial boiler range. It monitors the pressure difference across the appliance's air path and signals the control system when the required differential is not achieved. It is supplied under Broag part number S45772.

• The boiler locks out or fails to fire, with a pressure or air-related fault indicated.
• The fan runs but the appliance does not prove air flow and will not proceed to ignition.
• Intermittent lockouts that clear on reset and then return.
• The switch fails to change state when the fan is running, or shows no continuity change on test.
• Visible damage, contamination or blocked sensing ports on the switch or its tubing.

• Confirm the appliance model and that S45772 is the part number listed for it.
• Check the existing switch and its sensing connections for blockage or damage before condemning the part.
• Verify the fault is air pressure related and not caused by the fan, flue or wiring.
• Have the appliance isolated and, where required, work carried out by a competent heating engineer.