Hach Sigma 1600 Instrument Manual page 37

Appendix A
Problem
Sampler control panel and
refrigerator inoperative.
Sampler control panel
inoperative, refrigeration is
okay.
Fuse blowing.
Control panel operative, but
power ON does not light.
Sampler does not work in
flow proportional mode
(4–20 mA option).
Sampler does not respond
to contact closure signal
from flow meter.
Refrigerator not running.
Compressor will not start.
Unit runs in short cycles.
Compressor runs long or
continuously.
Refrigerator is noisy while
operating.
6507apdx_tbl.fm
Troubleshooting
Possible Cause
Blown main fuse.
Sampler disconnected from main power
source.
Blown front panel fuse.
Control panel harness connector
unplugged.
Improper fuse size or type.
Bad transformer.
Faulty power supply or component.
Defective power ON/OFF switch.
Bulb burned out.
Polarity incorrect or wires not connected.
4–20 mA signal grounded in series loop.
Voltage level too high on 4–20 mA.
EXT-MIN toggle switch is in wrong position.
A voltage or ground is present on contact
closure input leads.
Interval Between Samples thumbwheel
switch is set on a higher number.
EXT-MIN toggle switch is in wrong position.
Flow meter not sending signal to sampler.
Thermostat disconnected.
Line disconnect switch open.
Fuse removed or blown.
High pressure cutout due to insufficient air
cooling.
Low pressure cut out due to:
a. Compressor valve leak.
b. System refrigerant undercharged.
c. Restriction in expansion device.
Shortage of refrigerant due to leak.
Control contacts are stuck together.
Dirty condenser.
Loose parts or mountings.
Tubing rattle.
Bent fan blade.
Worn fan motor bearings.
Solution
Replace fuse/reset circuit breaker.
Reconnect.
Replace fuse.
Reconnect.
Replace fuse with 1 amp fuse
(Cat. No. 3318).
Check for shorted connections.
Isolate and replace bad component.
Check switch for short. Replace if necessary.
Replace bulb.
Check for proper polarity. Check wiring for good
non-resistant connections.
Check for complete current loop. Check for loss
of signal due to grounding.
Voltage on 4–20 loop must not exceed
15 V dc—otherwise damage may occur.
Place toggle switch in left EXT position.
Check input wires for presence of voltage or
ground, the sampler counts on release of dry
contact closure.
Double check the setting on 4-digit Interval
Between Samples thumbwheel switch.
Place toggle switch in left EXT position.
Check the signal and make sure it has a
minimum of 25 milliseconds duration.
Check that the thermostat wire leads are
connected.
Close disconnect switch.
Replace fuse.
Vacuum dust/debris from condenser coils.
a. Replace valve.
b. Fix leak, add refrigerant.
c. Replace device.
Fix leak.
Defrost and make sure connecting tube between
sample chamber and sample container is in
place.
Clean condenser.
Tighten and secure loose parts and mounting.
Reform tubing away from the obstruction.
Replace fan.
Replace motor.
Page 37
Troubleshooting