Super Site HMP155 Sensor Swap

Tools

• 5/16" Nut Driver
• camera / cellphone camera
• optional: something to keep the loose parts from flying off the tower

Process in field

• The HMP155 air temperature / relative humidity sensor is in what is called an aspirated radiation shield. The aspirator is a blowing fan that brings ambient air over the sensor head. They are secured to the North East leg of the platform tower at a variety of heights.
• There is a pvc 90* angle. Carefully loose it.
• Once the angle is off, the cable side of the sensor will be exposed.
• Take a photo of the old one's serial number as well as the marked height.
• Unscrew the data cable and secure it so it doesn't fall to a lower level.
• Carefully remove and watch that the insulation inside the fan tubing doesn't blow out and onto the ground below.
• Take a photo of the serial number for the replacement sensor.
• Place the sensor into the fan tubing and reconnect the data cable.
• reinstall the elbow.
• Done.

Process out of field

• Submit PR for either Vaisala or Campbell Scientific for an instrument recalibration and include a guess on cost of shipping.
• Contact company for RMA number, fill out online declarations and ship.
  • Vaisala has an online store where instrument info can be uploaded.
  • Campbell Scientific requires an email to their support to request an RMA.
• If I think a sensor is broken I send it to Vaisala or if it just needs recalibrating I send to Campbell Scientific. Vaisala will often replace at reduced cost broken instruments. Campbell Scientific has a cheaper recalibration price for working sensors.
• Box up and send via UPS with RMA info on outside of box.