Van Air Systems HL-200 - HL2000 - Manual (Page 20)

PAGE 20
MAINTENANCE & TROUBLESHOOTING SECTION 11
11.5 TROUBLESHOOTING
The following check list should be used as a guideline for troubleshooting problems. Each of the topics will reference other sections in this
manual for further information.
IS THE POWER ON?
Check the main power source. For dryers equipped with the
Standard Control Box make sure the Run button is pressed and
the Run LED is lit. For dryers equipped with Cycle Saver or
Emcon II Control Boxes make sure the Power switch is in the
ON position.
IS THE SYSTEM PRESSURIZED?
The dryer is designed to operate at 60 to 150 psig. Check the
upstream equipment and any isolation or bypass valves.
IS THE DRYER CYCLING?
• IS THE FAILURE TO SWITCH ALARM ACTIVATED?
If the dryer is not cycling the FAILURE TO SWITCH ALARM
should be activated. The dryer should be checked to determine
the cause of switching failure.
• IS THERE CONTROL AIR PRESSURE, 60 PSIG MINIMUM.
Make sure that the dryer inlet pressure is above 60 PSIG. Check
the control air filter element and replace it with a new element.
Reference Section 11.4 for element replacement instructions.
• ARE THE PILOT VALVES FAULTY? (SV1 & SV2)
Reference Section 11.5-3 for procedures to check the
operation of the 3-way valves.
Replace any faulty 3-way valves.
• IS THE INLET VALVE FAULTY? Reference Section 11.5-5 for
procedures to check the operation of the inlet transfer valve.
Rebuild or replace the inlet valve as necessary. Reference
Sections 12.9 & 12.10 for valve breakdowns and repair kit details.
• IS A PURGE EXHAUST VALVE FAULTY? Reference Section
11.5-7 for procedures to check the operation of the purge
exhaust valves.
Rebuild or replace the faulty purge exhaust valve. Reference
Section 12.11 through 12.15 for valve breakdowns and repair kit
details.
• IS AN OUTLET CHECK VALVE FAULTY? Reference Section
11.5-8 for procedures to check the operation of the outlet check
valves.
If a valve is faulty, replace it.
• IS THE PURGE METERING VALVE SET PROPERLY? Reference
Section 5.2 for purge metering valve settings and procedures.
If the purge metering valve requires adjustment, follow the
procedures in Section 5.2.
ARE THE TOWERS DEPRESSURIZING?
•ARE THE PNEUMATIC LIMIT SWITCHES FAULTY?
Reference Section 11.5-6 for procedures to check the operation
of the pneumatic limit switches.
If either of the pneumatic limit switches are faulty, replace them
both.
IS THE VISIBLE MOISTURE INDICATOR BLUE? Reference
Section 6.2 for an explanation of operation for the moisture
indicator.
• IS THE BLEED ORIFICE FITTING OR SINTERED MUFFLER
ON THE MOISTURE INDICATOR CLOGGED?
Inspect the bleed orifice fitting and the sintered filter on the back
of the moisture indicator. They can be cleaned or replaced.
IS THE DEW POINT ACCEPTABLE?
• ARE THE INLET CONDITIONS WITHIN THE SPECIFICATIONS?
Reference Section 3.1 for the inlet conditions of the dryer.
Correct the inlet conditions if necessary. Excessive inlet flow will
greatly reduce the performance of the dryer.
• IS THE PURGE METERING VALVE SET PROPERLY? Reference
Section 5.2 for purge metering valve settings and procedures.
If the purge metering valve requires adjustment, follow the
procedures in Section 5.2.
• WAS THE DESICCANT INSTALLED?
Make sure that the desiccant was installed. Reference Section
11.3 for desiccant replacement procedures.
• IS THE DESICCANT CONTAMINATED WITH LUBRICANTS?
Check the condition of the desiccant bed. If the bed is
contaminated with lubricants, replace the desiccant following
the procedures in Section 11.3.
• IS THE DESICCANT CONTAMINATED WITH MOISTURE?
If the dryer was operated under excessive inlet conditions, the
desiccant bed may be saturated with liquid moisture. Check
upstream equipment such as aftercoolers. Check the actual
inlet conditions, correct them and condition the bed following
the procedures in Section 5.3.
• ARE THE BYPASS VALVES OPEN OR LEAKING?
Check the valves (if installed). Repair or replace if faulty.
IS THE ENERGY SAVINGS BEING ACTIVATED?
(CYCLE SAVER AND EMCON II MODELS ONLY)
• IS THE CYCLE SELECTOR SWITCH SET IN THE "AUTO"
MODE?
The Cycle Selector must be set in the "AUTO" mode in order for
the dryer to activate the energy savings feature.
• IS THE DRYER BEING OPERATED AT THE MAXIMUM
OPERATING CONDITIONS? Reference Section 3.1 for rated
inlet conditions.
Little or no energy savings will occur if the dryer is being operated
at the maximum operating conditions.
• IS THE SOLENOID VALVE SV3 FAULTY? Reference Section
11.5-4 for procedures to check the operation of SV3.
If the valve SV3 is faulty replace it.
• ARE THE TOWER HUMISTAT AND SENSOR WORKING
PROPERLY?
Reference Section 11.5-9 for procedures to check the operation
of the sensor and humistat.
Check the sample cell isolation valve and the bleed orifice fitting.
If necessary, replace the bleed orifice fitting and/or the bleed
muffler.
• IS THE SAMPLE LINE DAMAGED OR PLUGGED?
Check the sample line following the procedures in Section 11.5-
10. Repair or replace the components as necessary.
11.5-2 CHECKING THE PROGRAMMABLE CONTROLLER
EMCON II MODELS ONLY:
The control system consists of three different control systems:
1. The programmable controller (PLC)
2. Input devices (24 volts DC components)
a. Pressure switches
b. Humistat(s)
c. Reset push-button(s)
d. Low voltage side of the Power ON/OFF Pushbutton
e. Cycle selector switch
3. Output components
a. Pilot valve(s)
b. Light(s)
c. General alarm contact
The PLC controls the cycling of the dryer. The program logic is
stored on an electrically erasable EEPROM. Loss of power to the
PLC will not cause loss of the logic program.
IS THE DEW POINT ACCEPTABLE?