Weekly; Monthly; Yearly; Returns To Manufacturer - Sigma HRD Serie Manual De Instrucciones

3. Check the switch-failure alarm light on the control
panel. If the light is on, refer to the Field Service
Guide for remedy.
4. Check the color of the moisture indicator in the
dryer outlet. When the dryer is functioning nor-
mally, the indicator is green. If the indicator is
yellow, refer to the Field Service Guide, page
1-20, for remedy.
For HRD-EM Series only:
5. Check system monitoring lights on bottom half of
indicating light panel. If any light is lit, see expla-
nations in Indicators section, page 1-7, for diagno-
sis and Field Service Guide, page 1-20, for
remedy.
6. Check the high-humidity alarm light on the con-
trol panel. If the light is on, refer to the Field Ser-
vice Guide for remedy.

Weekly

1. Check prefilter and afterfilter differential pressure
indicators. Replace filter elements in accordance
with manufacturer's directions.
2. Check exhaust muffler for discharge of air from
regenerating vessel. If no air discharges, disman-
tle and clean or replace muffler core. If no air dis-
charges when muffler is removed, call your local
distributor.
3. Check purge valves for leakage. Rebuild if any
leakage is evident.

Monthly

Inspect the internal float drain valve (if equipped)
every two to three weeks for excessive oil and water
by pressing the test valve on the bottom of the filter
unit. If more than one or two drops of oil leak out, the
drain valve should be cleaned or replaced as required.

Yearly

Maintenance kits for yearly preventive
maintenance are available from your local
dis tri b u tor. See A pp e n dix A fo r the
maintenance kit part numbers.
1. Inspect desiccant in dryer vessels. Depressurize
dryer according to Shutdown section of this man-
ual. Check for the following and correct as indi-
cated:
• Oil Contamination
If desiccant is contaminated with oil, check
drain valve on prefilter. Clean, repair or replace
HRD and HRD-EM Series (Bulletin 378)
Note
drain valve as necessary. Replace prefilter ele-
ment, then replace desiccant.
• Broken Desiccant (excessive dusting)
Desiccant dusting may be caused by air flow
surges, excessive air flow or pulsating air pres-
sure. Check and correct these conditions, then
replace desiccant.
2. Replace all solenoid and butterfly valve dia-
phragms and seats.
3. Replace all prefilter and afterfilter elements.

Returns to Manufacturer

If the dryer or a component of the dryer must be re-
turned to the manufacturer, first call your local dis-
tributor for a return authorization number and a
shipping address. Your distributor will inform you
whether the dryer or only the component must be re-
turned.

Desiccant Replacement

All dryers use activated alumina desiccant. To ensure
consistent dryer performance and to prevent excessive
dusting or premature desiccant breakdown, use only
factory-approved grades of activated alumina when re-
placing desiccant.
To replace desiccant:
DANGER
EXPLOSION HAZARD
Completely vent the internal air pressure to the
atmosphere before replacing the desiccant or
performing any maintenance work on your
dryer.
1. Depressurize dryer according to the shutdown in-
structions (page 1-12). Pressure gauges on both
vessels must indicate 0 psig before service contin-
ues.
2. Turn off power switch on control panel.
DANGER
SHOCK HAZARD
Portions of the electrical control circuit remain
energized when the power switch is turned
OFF. Disconnect the main power supply to the
dryer before performing maintenance on the
electrical system.
3. Disconnect the main power supply to the dryer.
4. Lock out and tag electrical power supply in accor-
dance with OSHA requirements.
1-13