Honeywell Water flow sensor C7195A 2001B

This water flow sensor detects the presence or rate of water flow in hydronic circuits. Depending on the model, it operates on a paddle, turbine, or ultrasonic principle, and uses a reed switch as the switching mechanism. The connection thread size varies by model. Sealing is done via a gasket or O-ring.

When selecting a replacement for this type of sensor, confirm the electrical output type (dry contact, open collector, or analogue) and the connection thread size. Verify the flow rate threshold at which the sensor switches, and check the maximum operating temperature and pressure ratings against the circuit's conditions. Ensure the replacement is compatible with the control board's input requirements, and inspect the sealing gasket or O-ring for integrity before installation.

Common failure modes include mechanical blockage of the moving element, loss of magnetisation in the reed switch, and corrosion of electrical contacts. Poor pipe alignment can also cause malfunction. To diagnose, inspect for these issues and compare the sensor's switching behaviour with the expected flow rate.