Pneumatech PHM Series - Page 23

22
Table 2 — Troubleshooting Guide for PHM Mini Series Heatless Regenerative Dryers
Symptoms Cause Remedy
A. Elevated Dewpoint 1. Low inlet pressure.
2. Excess moisture carryover.
3. Excess gas inlet flow.
4. Desiccant coated with oil.
5. Low inlet air temperature.
1. Increase pressure (minimum 75
PSIG), or reduce flow.
2. Check drains at aftercooler and
prefilter.
3. Check the total output of
compressors.
4. Depressurize the dryer and
replace the desiccant.
5. Raise inlet temperature above
75°F (24°C).
B. High back pressure on
regenerating tower.
NOTE: The tower should be at ‘0’
PSIG during regeneration cycle.
Any back pressure will result in
improper regeneration.
1. Muffler plugged.
2. Shuttle valve leaking.
1. Replace mufflers.
2. Clean, repair or replace faulty
valve.
C. Excessive flow through mufflers. 1. Check valves sticking.
2. Purge valve sticking.
3. Timer short-circuited.
1. Clean, repair or replace valve.
2. Clean, repair or replace valve.
3. Replace faulty timer.
D. Failure to switch. 1. Inlet valves did not switch.
2. Timer short-circuited.
1. Clean, repair or replace valve.
2. Replace faulty timer.
E. High pressure drop in dryer. 1. Desiccant retainer screens
plugged.
2. High purge flow.
3. Purge valve stays open.
1. Replace desiccant retainer
screens.
2. See. C1 to C3.
3. Clean, repair or replace valve.
F. Dryer fails to purge. 1. Orifice plate plugged.
2. Purge valve stuck closed.
1. Clean the orifice plate.
2. Clean, repair or replace valve.