Super Site CNR4 desiccant refresh procedure

Pictures to take

• Instrument
• flipped
• sensor cables ends

Tools

• Small channel lock pliers
• camera / cellphone camera
• optional: cloth or towel to catch small screws and to keep the glass protected
• bubble level
• 1/2" Nut Driver
• 1/2" box wrench
• 5/16" nut driver
• Campbell Scientific #2 phillips screwdriver
• Stubby #2 phillips screwdriver

Tower Instrument Process in field

• bring the tools to the top of the tower
• bring the replacement instrument to the top of the tower
• use the 1/2" box wrench & 1/2" nut driver to loosen the ubolts holding the cross arm in place.
• use the 5/16" nut driver to loose the hose clamp (loosen but do not remove)
• carefully wiggle / bump / shimmy the cross arm back to the platform.
• once the cabling is very close carefully unscrew the CNR4 from the slender cross arm.
• move the sensor to the tower platform
• use one of the phillips screwdrivers to remove the plastic radiation shield.
• use one of the phillips screwdrivers to remove the machine screws securing the CNR4 to the heater/fan part
• once the pieces are separated, use the small channel lock pliers to unscrew the sensor cables.
  • Note that there are three cables. The outside the case one is for the fan/heater. (four pins I believe)
  • The other two are for the net radiometer. I believe the one on the left is for the radiation and has eight pins. The one on the right has less pins and is used to measure the internal temperature of the radiometer.
• use a screwdriver to remove the base plate machine screws. Be careful the screws have a soft metal head that is very easy to strip.
  • (asterisk, one of the newer units has a port for accessing the desiccant that is opened using the small channel lock pliers)
• Remove the plate and set it aside carefully. There is also an o-ring. Take care not to let it fly off the tower. The white short cylinder is the desiccant. Remove and replace with the new / refreshed one.
• Reverse these steps.

Forest Floor Instrument Process in field

• bring tools and set on ground.
• twist the sensor one-half turn so it is upside down. (counter clock-wise)
• use one of the phillips screwdrivers to remove the plastic radiation shield.
• use one of the phillips screwdrivers to remove the machine screws securing the CNR4 to the heater/fan part
• once the pieces are separated, use the small channel lock pliers to unscrew the sensor cables.
  • Note that there are three cables. The outside the case one is for the fan/heater. (four pins I believe)
  • The other two are for the net radiometer. I believe the one on the left is for the radiation and has eight pins. The one on the right has less pins and is used to measure the internal temperature of the radiometer.
• use a screwdriver to remove the base plate machine screws. Be careful the screws have a soft metal head that is very easy to strip.
  • (asterisk, one of the newer units has a port for accessing the desiccant that is opened using the small channel lock pliers)
• Remove the plate and set it aside carefully. There is also an o-ring. Take care not to let it fly off the tower. The white short cylinder is the desiccant. Remove and replace with the new / refreshed one.
• Reverse these steps.