Sigma HRD Serie Manual De Instrucciones página 23

Problem
Inlet air flow higher than the sizing
condition.
Liquids entering the dryer inlet.
Inlet air temperature higher than sizing
condition.
Dew point too high
or too low
Desiccant dusting.
Desiccant coated with oil.
Mufflers plugged; excessive purge
back pressure.
Excessive pressure
drop in prefilter and
Filter elements dirty.
afterfilter.
Inlet and/or outlet screens on desic-
Excessive pressure
cant towers dirty.
drop in dryer.
Excessive flow rate.
No demand for outlet air.
Power failure.
Solenoid valve stuck shut.
Failure to switch.
Solenoid valve stuck open.
Shuttle valve stuck.
Mufflers plugged; no hiss from muf-
flers when purging.
Low air pressure to air-operated let-
down valves.
Microcomputer failure*
Power failure.
Dryer cuts off
Power is not connected to microcom-
automatically.
puter.*
Microcomputer failure.*
Loose or incorrectly installed ribbon
cable.*
Clogged diaphragm.
Automatic drain
valve continually
Short in electrical component.
discharging/venting
No electrical power.
Automatic drain
Timer malfunction.
valve not
Solenoid coil malfunction.
discharging
Clogged ports.
No electrical power.
No response when
push-to-test button
on automatic drain
Timer malfunction.
valve is pressed
* HRD-EM Series Dryers only.
HRD and HRD-EM Series (Bulletin 378)
Possible Cause Remedy
Reduce inlet flow to sizing conditions.
Check the inlet air line for liquids. Inspect prefilter and drain
valve. Clean, repair or replace drain valve.
Check the compressor aftercooler and cooling system. Re-
duce inlet air temperature to sizing condition.
Check air pressure, airflow and airflow surges, and correct
as necessary. Replace desiccant.
Check prefilter and drain valve. Replace prefilter element.
Clean, repair or replace drain valve as necessary. Consult
factory concerning need for desiccant replacement.
Clean or replace muffler cores. If no air is discharging when
mufflers are removed, consult the factory.
Replace elements.
Clean or replace screens; follow desiccant removal instruc-
tions in Maintenance section, then disconnect inlet and out-
let piping to remove screens.
Check flow rate of inlet air. Reduce to sizing condition.
Normal automatic shutdown; dryer operation and airflow
switching resume with demand for air.
1. Check power with voltmeter.
2. Check dryer fuse in the electrical enclosure. Replace as
necessary.
Replace solenoid coil or complete valve.
Remove, dismantle and clean.
Dismantle and clean. Replace if problem continues.
Clean or replace cores.
Adjust purge air regulator to above 60 psig.
Consult your local distributor
1. Check power with voltmeter.
2. Check dryer fuse in the electrical enclosure. Replace as
necessary.
With main power off, plug terminal strip into computer
board.
Consult your local distributor.
Ensure that all ribbon cables are installed securely. If dryer
still will not start, contact your local distributor.
Clean diaphragm.
Check and replace connector or timer assembly.
Check and correct power supply and connections.
Replace timer assembly.
Replace solenoid coil.
Clean ports.
Check and correct power supply and connections.
Replace timer assembly.
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