A.O. Smith 110-310-510 – ERROR CODE 441 [510 (T-D2)] FLOW SENSOR

Part of an Easy?Link system (510 (T?D2) only), the master unit signaled for an additional heater to activate and it did not.
1) Verify that water is being supplied to the heater in error.
2) Verify that the wires are connected to the computer board.
3) Check the inlet filter for any debris. See p. 21.
4) Check the flow sensor for debris.