60
HDK-MT350_EN_06
Identifying and eliminating faults
Overview of faults
There are different types of fault. In the case of most electrical faults (e.g. short-
circuit, defective fuses, etc.) the expansion valves V3/V4 close, the inlet valves
V1/V2 open and the program stops. In the case of some process faults, the dryer
will continue to operate for some time. Faults on the dryer (or 'adsorber') become
noticeable e.g., due to unusual noises and dam pressures.
The following table shows who is allowed to rectify a fault: the technical
personnel of the operating company or trained maintenance personnel
Table of possible faults
Some faults cannot be traced back to valves not opening or closing correctly. The
measures for rectifying these faults are summarised at the end of the chart.
Fault
Possible cause
Remedy
T
ech
n
ical
p
e
rs
o
n
n
e
l
S
er
vi
ce
te
c
h
n
ic
ia
n
Pressure dew point
is not reached
Insufficient operating pressure.
Increase operating pressure.
Differential pressure on the prefilter
is too high.
Check differential pressure on the prefilter, if
necessary renew filter element.
Compressed air volume flow is too
high.
Reduce compressed air flow rate.
Compressed air inlet temperature is
too high.
Reduce compressed air inlet temperature or pre-
connect a compressed air cooler.
Condensate trap (option) on the
prefilter does not work.
Check function of the condensate trap (option), if
necessary clean or renew.
Desiccant is contaminated or too
old.
Check prefilter for contamination, if necessary
renew element.
Check desiccant for contamination, if necessary
renew desiccant.
Control board is defective.
.Check the fuses (switch cabinet, supply line)
and renew the PCB if necessary
Regeneration gas too low.
Check function of valve V3 / V4 and muffler, if
necessary, replace muffler or filter element.
RV1 – RV4 defective
Replace RV valve.
sensor defective
Replace sensor.
Vessel pressure is
too low
Differential pressure on the prefilter
is too high.
Check differential pressure on the prefilter, if
necessary renew filter element.
Excessive dam
pressure during
regeneration
Muffler soiled
Check mufflers for contamination, clean if
necessary, and possibly renew.
V3/V4 valve does not open
correctly.
see *
Dust sieve is contaminated.
Clean or renew dust sieve.
