16
5.7 Alarm L7 - Failure to repressurize, left tower, regeneration cycle
1. Faulty left tower pressure switch (PS1) • See Section 5.1.3.
2. Left purge valve (V3) failed to close
• See Section 5.1.5.
3. Left depressurization valve (V5)
• See Section 5.1.6.
failed to close
4. Repressurization valve (V15) failed
• Loss of pilot air - see Section 5.1.4.
to open
• Pilot valve (V16) failure - check valve operation. Repair or replace as
necessary.
• Repressurization valve (V15) - examine valve and actuator for damage.
Repair or replace as necessary.
5. Repressurization orifices (O1,O2)
• Check orifices for obstruction and clean as necessary.
blocked
6. Left purge check valve (V9) leaking
• Check for reverse air flow through heater and blower, i.e., out of the
blower intake filter (F1) and examine check valve internals. Repair or
replace as necessary.
CAUTION:
Air flowing backwards through heater and blower may be
very hot.
5.8 Alarm L8 - High outlet dew point, left tower, drying cycle (optional)
1. Incomplete regeneration
• Check for Alarm L6 (see Section 5.6)
2. Desiccant bed overloaded
• See Section 5.2.1
3. Loss of desiccant drying capacity
• See Section 5.2.5
4. Insufficient sample flow to monitor
• Ensure isolation valve in sample line is fully opened.
• Ensure flow cell inlet filter is not clogged. Clean or replace.
• Ensure flow cell outlet (orifice) fitting is free of obstructions.
5. Alarm set point too low
• Check alarm set point (see menu #7) and adjust as necessary for dryer
operating conditions.
5.9 Alarm R1 - Low tower pressure, right tower, drying cycle
1. Loss of dryer air supply
• Check compressor supplying dryer.
2. Excessive air demand
• Check equipment downstream of dryer.
3. Faulty right tower pressure
• Check pressure switch operation using right tower pressure gauge
switch (PS2)
(PI2) for comparison. Replace switch if defective.
4. Right inlet valve (V2) failed to open
• Loss of pilot air - ensure manual drain valve on bottom of pilot air filter
(F2) is fully closed, ensure pilot air filter cartridge is not clogged,
ensure pilot air shutoff valve (V17) is open.
• Inlet pilot air valve (V12) failure - check valve operation. Repair or
replace as necessary.
• Right inlet valve (V2) - examine valve and actuator for damage. Repair
or replace as necessary.
5. Right purge valve (V4) failed to close
• Check for air flow out of right purge valve or exhaust piping indicating
valve is not completely closed.
• Loss of pilot air - see Section 5.9.4.
• Right purge pilot valve (V14) failure - check valve operation. Repair or
replace as necessary.
• Right purge valve (V4) - examine valve and actuator for damage.
Repair or replace as necessary.
6. Right depressurization valve (V6)
• Check for air flow out of right depressurization muffler (M2) indicating
failed to close
valve is not completely closed and examine valve. Repair or replace as
necessary.
7. Left outlet check valve (V7) failed
• Indicated by excessive flow out of left purge valve (V3), examine valve
to close
internals. Repair or replace as necessary.
8. Right purge check valve (V10) leaking
• Indicated by excessive flow out of left purge valve (V3) or reverse air
flow through heater and blower, i.e., out of the blower intake filter
(F1), examine valve internals. Repair or replace as necessary.
CAUTION:
Air flowing backwards through heater and blower may be
very hot.
POSSIBLE CAUSES
CORRECTIVE ACTION
