A-5
“Oil-Less” Scroll Laboratory Air
4107 9006 25.11
Appendix A: Desiccant Dryer
Problem
Possible Causes
Solution
Dew point degradation
Desiccant is contaminated. The
“white” desiccant beads may
appear discolored and dirty if
contamination has occurred.
Shutdown and depressurize the dryer.
Inspect the desiccant and replace if
fouled. Inspect any existing pre-fi lter
if fouling is noted.
Union or other piping/
component leaks at dryer outlet
manifold or downstream of dryer
outlet.
Soap test the dryer outlet manifold
and piping downstream of dryer.
Repair all leaks noted.
Back pressure on a
desiccant chamber during
the regeneration cycle.
Dirty or fouled purge muffl
er
Switch off power and remove purge
muffl
er and clean using an air nozzle,
or replace.
Outlet check valve leaking
Repair check valve
NOTE:
The presence of backpressure will result in insuffi
cient regeneration followed by dew point
degradation. An off -line chamber’s pressure
MUST be less than 3 psig
throughout all regeneration
cycles.
A.3 Troubleshooting
