Bradford White IGI-180R-10 Service Manual page 20

V - SEQUENCE OF OPERATION
(cont.)
When the hot water tap is turned off, the water flow sensor stops revolving, and the magnetic pulse
ceases, indicating to the PCB that there is no water flowing, in turn the PCB closes the gas valves. The
combustion fan continues to operate for 65 seconds. This will provide quicker ignition when the tap is
turned on and off in rapid succession, and removes the need for a pre-purge cycle allowing the burner
to re-light immediately when a hot water tap is opened again.
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