Denco C120-3, Operation Manual, Page: 28 / 32

Fault Finding
The following fault finding chart relates various symptoms and faults of the refrigeration system.
Before attempting to identify a refrigeration system fault it must first be established that the DESIGN
CONDITIONS to the compressed air system are being met i.e. flow, pressure and temperature.
Excessive overload will be caused by:
1. Excessive compressed air inlet temperature.
2. Compressed air pressure too low.
3. Compressed air flow in excess of design.
4. High ambient air temperature.
Dirt, scale and/or excessive oil in the compressed air may cause one or more of the following:

Drain blockage leading to moisture being carried over into the compressed air system.

Excessive pressure drop in compressed air circuit.

Excessive fouling of the heat exchanger internal surfaces.
PROBLEM CAUSE SYMPTOM REMEDY
Compressed air temperature
too high. The digital display panel
indicates
a value > 4C° permanently Return the air inlet
temperature to within the
limits.
Compressed air flow rate too
high. The digital display panel
indicates
a value > 4C° permanently
Correct the air flow rate
to within the limits of the
dryer.
Compressed air pressure too
low. The digital display panel
indicates
a value > 4C° permanently Correct the pressure to
within the limits.
Ambient temperature too high. The digital display panel
indicates
a value > 4C° permanently
Correct the temperature
to within the limits.
Dirty fins of the condenser. The digital display panel
indicates
a value > 4C° permanently
Clean the condensing
unit fins.
Condensing unit clogged. The digital display panel
indicates
a value > 4C° permanently
Clean the condensing
unit face.
The fan runs backwards (three-
phase) The digital display panel
indicates
a value > 4C° permanently Correct electrical
connection (phase
inversion)
Refrigerant gas leak The compressor top is very
hot;
Low pressure
Find the leak and repair
it.
A
Dew point
too high
The HP Pressure switch has
tripped The digital display panel is
OFF See note E.