Daewoo Novus F3CBF, Manual

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3-100 INSPECTION AND MAINTENANCE
(6) Troubleshooting for air dryer
Daily inspection and periodic inspections will prevent the greater portion of air dryer troubles.
In the event of troubles or complaints as listed, follow the correction precedures to correct the
difficulty.
Complaints
Water comes
out from main
tank.
Drain valve fails
to drain.
Inside of air
dryer has been
frozen.
Air leaks from
drain valve
Excessively low
pressure of
main tank
Cause
1. Desiccant has been saturated.
2. Cut-off pressure of governor is so low
that purge valve won't open.
3. Failure to change desiccant or oil filter
within scheduled period.
4. As the purge time is less than the rated
time(50 seconds), desiccant is not re-
covered sufficiently.
1. Freezing of air dryer due to heater
trouble
2. Failure to regularly change desiccant
3. No operation of purge valve due to the
entry of foreign substances into drain
valve
1. Misattached dryer body or exposed to
cold weather at -30

C while traveling
2. Heater has been short-circuited and no
heating
3. Thermostat has been short, resulting in
failure of heater.
4. The dryer's temperature drops signifi-
cantly due to ice or snow stuck to its
body
5. No operation of heater due to discon-
nection of the electrical wiring for heater
or thermostat
1. Poor contact of valve seat due to the
entry of foreign substances into valve
1. When the check valve of main tank fails
to perform backward flow checking op-
eration with compressor in unload
cycle, air can be leaked through the
main tank drain.
Correction
Check and drain the main tank until the des-
iccant is dried up.
Increase pressure for governor to 6.45 (DR- 5:
7.2) kg/cm
2
or higher.
Change desiccant kit at end of every 12
months or 90,000km operation.
1) If cut-off pressure of governor and closing
pressure of relief valve are low, purge time
also is shortened, resulting in failure in
recovery of the desiccant.
2) In the case of purge by relief valve, if cut-
off pressure of governor and closing pres-
sure of relief valve are low, purge time also
is shortened, resulting in failure in recov-
ery of the desiccant.
1) Change faulty heater.
2) When the trouble is located in thermostat,
change it.
Change desiccant kit at end of every 12
months or 90,000km operation.
Disassemble and check the valve, and re-
place the valve, if necessary.
Correct the position of dryer body or install a
wind screen.
1) Use a tester to check the heater for short-
circuit.
2) If heater has been short out, change it with
a new one.
Leave thermostat at temperature of 0

C or
below and use a tester to check it. Add heat
to thermostat by hand to check for OFF state
and change it if required.
Remove ice or snow so carefully as not to
cause damage to dryer body and electrical
wiring connections for heater.
Check heater and thermostat for connection.
Disassemble and check the valve, and change the
valve kit if required. When damage is found at the
wet moving part of valve body, change the valve.
Disassemble and check the check valve lo-
cated between main tank and purge tank, and
change it if required.
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