Technical Service Bulletin - FV Sensor SP20172 Low Resistance

Reason:

The installed FV sensor features a resistance level that is below the minimum set point of the gas valve. This results in valve lock-out that can only be corrected via installation of a sensor with a minimum resistance level about 11k Ω.

Service Action Required:

If give a FV sensor error for any FV sensor (SP20172):

  1. Using a multimeter to check resistance, remove the sensor from its bracket on the base ring of the water heater and disconnect both wires to the sensor.
  2. Take a resistance reading between the two wiring terminals of the FV sensor and note the resistance value.
  3. If the resistance reads under 11k ohms or above 45k ohms, the FV sensor should be considered suspect and replaced.

NOTE: When checking the resistance of the sensor, check with wires attached to sensor with sensor unplugged from the valve. If you get an invalid reading, then check accross the sensor only. 

If wires and sensor check are valid, then proceed to next steps of troubleshooting. Sensor is not defective.
If wire harness or sensor checks are invalid, then replace appropriate part.

Unlocking a White Rogers gas valve after changing the FVS

  1. Reconnect power and turn unit on, the FV error code wil re-appear
  2. Press and hold left and right arrow keys on the control valve at the same time until the green light begins to link
  3. Release buttons quickly
  4. Press left and right buttons in the following sequence within 30 seconds
    left, right, left, left  right, left, right, right
  5. When the valve resets all the lights will come on


Unlocking a Honeywell gas valve after changing the FV

  1. Turn dial on gas valve all the way to the left
  2. Turn unit on
  3. Cycle the dial full right to full left 7 times in 10 seconds
  4. Valve will unlock and tank will light