Pure Air Circulator Unit
Chapter 6: Maintenance
Page 6
TTN004825-D02
Chapter 6
Maintenance
6.1. General Care Information
The desiccant filter that removes the moisture requires the most attention. The filter contains blue, indicating
desiccant. When indicating desiccant turns pink, the desiccant needs to be changed. Filter 1 and 2 may be inspected
through the vent holes in the top panel of the PACU unit.
Both Filters 1 and 2 are indicating when saturated and can easily be inspected for changing by their indicating color
change to pink. Filter 2 and Filter 3 should be changed together. The time period between filter changes depends
upon the chamber that is being filtered. When the unit is new, the flow meter typically peaks as the maximum pump
speed is approached. Should the filters be saturated, a reduced amount of air flow will show on the flow meter. We
have run the unit for hundreds of hours with no degradation of flow or increase in particle count. If it is deemed
necessary to change the particulate filters, they should be changed simultaneously.
6.2. Filter
Replacements
Thorlabs uses indicating desiccant in the Pure Air Circulator Unit Filter 1, which changes color from blue to pink
when the desiccant is saturated with water. Filter 2 also uses a blue indicating material that will change its color to
pink when saturated. If either filter shows signs of saturation please replace them. The vent holes located on the
top panel of the PACU system offer a convenient way to check for saturation without having to disassemble the
unit. When used in a closed-loop system, the particulate filters used in the PACU should greatly outlast the
desiccant. Replace the particulate filter when you notice a decrease in flow rate at a given pump speed. The
instructions below describe the necessary steps to replace any of the three filters.
Thorlabs supplies replacement filters online at
www.Thorlabs.com.
Required Tools:
Phillips Head Screwdriver
Flat Head Screwdriver
9/16” Wrench (Not Socketed) or Adjustable Wrench
Teflon Tape
6.2.1. Step One: Top Panel Removal
SHOCK WARNING
Before removing any of the panels to gain access to the inside of PACU disconnect AC power.
Make sure the power cable is disconnected from the unit.
To remove the top panel of the PACU system, use a Phillips head screwdriver to remove the four screws located
in the four corners of the panel (as shown in Figure 1).
Figure 1
Screw Locations
Figure 2
Removing Panel
After all four screws have been removed; the top panel can be removed by sliding the top panel towards the back
of the system which will free the opposite side to be gently lifted. If you find it difficult to slide the top panel
