Replace sensors

Disconnect the power supply at the bottom of the AQY 1 unit.

Remove the front cover by loosening all 4 screws (they won't come out of the casing).

Unscrew the modem/USB mounting bracket.

Disconnect the USB connections and remove the entire bracket with USB backup and modem attached.

Disconnect the white connector at the top of the PM sensor.

Separate the sensor from the metal bracket by disconnecting the white spacers.

Pull the sensor out of the sample tube (wiggling or rotating may be required).

Insert the new PM sensor into the sample tube.

Connect the sensor to the metal bracket using the white spacers.

Connect the white connector at the top of the new sensor.

If you're only changing the PM sensor, go to step 6 to reset its calibration parameters.

Disconnect the 3 white data connections from the NO2/O3 sensor board. The connections are labelled:

PM = PM

T/RH = Temperature/RH

RPi = Raspberry Pi

Unscrew the positive and negative power supply cables from the sensor board.

Unscrew the entire sensor board -1 screw underneath and 2 on the backplate.

Remove the sensor board by gently pulling it vertically to free the sensors from their grommets.

Never directly touch the exposed NO2 sensor at the bottom. If it becomes disconnected from your replacement sensor assembly, grip the sides of it when reconnecting.

Connect the positive and negative power supply cables to the replacement sensor board. Double check the polarity.

Align the NO2 and O3 sensors with the appropriate holes in the base and push the sensor board into position.

Screw the new sensor board in, bottom screw then backplate screws.

Re-connect the data connections to the correct terminals.

Reconnect the USB backup and modem to their USB cables and screw the bracket back onto the backplate.

Replace the front cover ensuring the front vent is at the top with the opening pointing down.

Reconnect the power supply.

After replacing the PM2.5 sensor, you need to reset its calibration parameters.

Connect to the monitor via Aeroqual Connect or Aeroqual Cloud.

Ensure the monitor is in Normal operation and not displaying an error message. If an error is displayed, check the PM2.5 sensor and connections.

Enter the Calibration and Service app and select Particles from the drop-down.

Select the PM2.5 raw channel and check the New offset is set to 0.0 and the New gain is set to 1.0.

Don't adjust theses parameters for any other particle channel.