Troubleshooting - SPX Hankinson HHE Series Instruction Manual

11. TROUBLESHOOTING

SYMPTOM
11.1 Indicator lights not No power to unit.
illuminated
Off/On switch turned off.
Blown fuse.
Off/on switch or board malfunction.
11.2 Moisture indica- Design conditions exceeded.
tor turns yellow
(elevated outlet
Spent desiccant (useful service life has ended).
dew point)
Contaminated desiccant (e.g. with oil)
Saturated desiccant (saturated with water)
11.3 Premature satura- Insufficient purge flow - Purge pressure too low
tion of desiccant
Incomplete tower depressurization (tower pressure
greater than 2 psig) - clogged mufflers
Incomplete tower depressurization -
Purge/repressurization valve fails to open
Insufficient purge time - Incorrect controller settings
Insufficient purge time - Faulty controller
11.4 Tower fails to Purge/repressurization valve fails to close (air loss
repressurize to line from mufflers during tower repressurization portion
pressure of cycle)
Insufficient purge flow - Purge pressure too low
11.5 Excessive purge is Excessive purge flow - Purge pressure too high
discharged during
Inlet switching valve fails to close.
purge cycle
(Models 40 through 3000) Shuttle Valve; or (Models
4100 through 5400) same tower Outlet Check or
opposite tower Purge Check Valves fail to close
11.6 Excessive desic- Fluidization of desiccant bed - design conditions for
cant dust down- maximum rated flow exceeded
stream
Fluidization of desiccant bed -
Rapid repressurization of offstream tower due to:
Faulty timer
Insufficient purge flow - purge pressure too low
11.7 Switching Failure Faulty pressure switches or control board
Alarm
Offstream tower did not de-pressurize in time and/or
(Level 1 & Level 2
below 10 psig
Controllers only)
Offstream tower did not re-pressurize in time and/or
above 10 psig
POSSIBLE CAUSE(S) CORRECTIVE ACTION
Check voltage at terminal board.
Turn on.
Replace fuse.
Replace board.
Refer to Sections 4 & 9 to determine if dryer is being outside of design
limitations.
Replace desiccant.
Take corrective action. Refer to Section 4.1 to determine proper prefiltra-
tion before changing desiccant.
Refer to 11.3 for corrective action. Operation at reduced flow may reacti-
vate desiccant beds until desired outlet dew point is achieved.
Refer to Section 9 to determine correct Purge Pressure Indicator setting.
Replace muffler inserts.
Verify voltage to pilot solenoid valve. Check pilot air pressure (60-120 psig
required). Verify proper actuator operation.
Refer to Section 7 or 8 to determine correct controller cycle settings.
Refer to Section 7 or 8 to verify proper time sequence. Replace controller
board as required.
Verify removal of voltage to pilot solenoid valve. Verify proper actuator
operation. This is a spring-assisted, normally closed valve. Check valve for
obstruction or seat damage.
Refer to Section 9 to determine correct Purge Pressure Indicator setting .
Purge Pressure Adjustment Valve should never be completely closed.
Refer to Section 9 to determine correct Purge Pressure Indicator setting .
Verify voltage to pilot solenoid valve. Check pilot air pressure (60-120 psig
required.) Verify proper actuator operation. Check valve for obstruction or
seat damage.
Repair or replace valve(s) as needed.
Refer to Section 4 or 9 to determine if dryer is being operated outside of
design limitations.
Refer to Section 7 or 8 to verify proper time sequence.
Refer to Section 9 to determine correct Purge Pressure Indicator setting .
Replace components
Check mufflers, check or shuttle valve(s), inlet switching and purge/
repressurization valves, purge pressure adjustment, and controller set-
tings.
Check air supply to dryer, purge/repressurization valve, purge pressure
adjustment, and controller settings.
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