SECTION 2 RH SERIES—HIGH TEMPERATURE
33
Dryer-on light is lit but
refrigerant compressor is
not operating
Clogged condenser fins Clear fins of all obstruc-
tions
The clogged fins in the condenser will
restrict the air passage and reduce
the refrigeration capacity, causing
high temperature in the evaporator.
Air condensers should be periodically
checked and cleaned.
Too much air flow Check actual flow
through the dryer
This dryer is designed for a maximum
air flow. If too much air is pumped into
the dryer, water removal capacity
decreases, resulting in liquid carry-
over downstream. Check the rated
output of the air compressor and
make sure that it matches the dryer
capacity.
Dryer-ON light is lit but
refrigerant compressor
does not run
Faulty electrical wiring Inspect the circuit The compressor-on light should be
wired into the refrigerant compressor
circuit.
Refer to the electrical and wiring dia-
gram for proper connections.
One electrical protection
has tripped
Reset the protection or
replace the blown fuse
The dryer is protected by a fuse and/
or overload relay that can trip.
Reset or replace blown fuse once, but
do not insist if it trips again. Instead
have a qualified refrigerant technician
check the complete dryer thoroughly.
Dryer-on light is lit but fan
does not come ON
Fan has to run if refriger-
ant high pressure has
reached upper set point
Check the compressed
air flows through the
dryer. Check to make
sure that the fan blades
are free to rotate.
Fan is automatically turned ON/OFF
in order to keep the refrigerant pres-
sure to a minimum value. The fans
might stop if the pressure setting is
incorrect
Dryer on light is lit but fan
motor of aftercooler does
not run
Inlet air temperature may
be too low
Increase the inlet air tem-
perature
The fan motor of the aftercooler is
designed to run if the inlet air temper-
ature is equal or greater then 95F. In
case it is less then that temperature
then the fan motor of the aftercooler
does not start to run.
When compressor starts, it
vibrates a lot and makes
mechanical noise
Compressor is sucking
liquid refrigerant at start
up.
Be sure that pre-heating
period of minimum 4
hours has elapsed for
dryers equipped with
crankcase heater (all
models equal to and
larger than 250CFM)
Refrigerant may move between the
receiver when refrigerant compressor
is stopped and not heated, especially
if it has been non-operational for a
long time
This migration may cause liquid shock
in valves specially on dryers contain-
ing more refrigerant
PROBLEM POSSIBLE CAUSE REPAIR COMMENTS
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