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Error Code E90 (Flow Sensor)
1. Check the connection of the flow sensor. Make sure connectors are in good contact. Ensure
that the pins inside the connector are not broken or bent. Color and style of connector may
be different from the one shown in the photo below. To ensure you are looking at the right
cable, follow it back from the PCB terminal marked FLOW.
2. Proceed to testing the unit if the connection was bad to verify. Go to the next step if problem
is not fixed.
3. Check the flow sensors. Short the terminal to simulate an inactivated flow sensor after
turning on the system and run the filter function. Flow center is located near the air blower.
Replace the defective flow sensor if the system does not display Code 90 and turn off.
a. Start by unscrewing the PCB cover to reveal the PCB. Disconnect the flow sensor
terminal on the PCB as well as terminals H&G.
b.
Release the screws for Flow sensor replacment.
