Keltech KRAD M Series, Инструкция по эксплуатации, Страница: 60 / 62

Page 60
Problem Possible Cause Repair Comments
Dryer is
switched on,
indicator light
is lit but the
refrigerant
compressor
does not turn on. The connection has
inverted phases Invert two phases 3-phase dryers are equipped with a phase controller
to avoid the fans from turning in the opposite
direction.
Refrigeration unit is not
functioning Check refrigeration comp-
ressor Several factors can cause compressor failure.
A qualified refrigeration technician needs to check
all the electrical and refrigerant circuit and controls.
The refrigerant highpressure
protection has tripped The refrigerant safety high
pressure switch has tripped. The dryer is protected against excessively high
refrigerant pressure. If the condenser efficiency has
reduced, the switch will trip. Manually reset the
switch.
In case of water cooled con-
densers, check the water
control valve
Excessive ambient tempe-
rature Be sure that dryer is working
in temperatures lower than
the
design conditions.
Designed conditions and
correction factors are desc-
ribed
in this manual. A high ambient temperature may cause the
refrigerant system to operate at higher than normal
pressures. Results will be higher than normal
evaporator temperature.
lmportant: adequate air circulation around the dryer,
and proper ventilation in the equipment room should
guarantee a low enough ambient temperature.
Dryer is
switched on,
but the refrigerant
compressor
does not turn on. Excessive temperature on
crankcase of compressor. Allow time to compressor to
cool down. Reason may be a
possible incorrect adjustment
of hot gas bypass valve or
shortage of refrigerant Compressor is protected against overly high
temperatures of the crankcase by a thermal switch.
Excessive compressed
air inlet temperature. Be sure that dryer is working
in temperatures lower than
design conditions. The dryer is designed for working in calculated
conditions (see description in this manual).
If conditions are exceeded, the dryer will be
overflowed, dew point will go up and protecting
devices can switch off.
Clogged condenser fins or
clogged water condenser.
Possible high crankcase
temperature
Possible loss of phase
Possible low voltage causing
overload trip Possible failed
compressor Clear fins or water condenser
of all obstructions. The clogged fins in the condenser will restrict the
air passage and reduce the refrigeration capacity,
causing high temperature in the evaporator.
Same will occur if water condenser is clogged with
mud or dirt. Air condenser and water condenser
should be periodically checked and cleaned.
Protect water circuit by an adapted filter.
Too much compressed air
flow. Check actual flow
through the dryer. This dryer is designed for a maximum air flow at
design conditions. If too much air is pumped
into the dryer, water removal capacity may not be
sufficient, resulting in liquid carryover down stream.
Check the rated output the air compressor.
Faulty electrical wiring Inspect the circuit The compressor-on light should be wired into the
refrigerant compressor circuit. See wiring diagrams
in this manual.
One electrical protection
has tripped. Reset the protection or
replace the blown fuse. The dryer is protected against high amp draw by
fuse and/or overload relay that can trip in case of
need. Reset or replace fuse once, but do not persist
if it trips again, request assistance from a qualified
refrigeration contractor.
Dryer is switched
on but fan is not
running. Fan has to run if refrigerant
high
pressure reaches upper set
point. Check that compressed air
flows through the dryer.
Check
that fan blades are free to
move.
Check the fan pressure
switch. Fan operates automatically to keep refrigerant
pressure below the maximum value. The fan can
stop if pressure is under the recommended setting.
When compressor
starts, it vibrates
a lot and makes
mechanical noise. Compressor is slugging
liquid refrigerant
at start up. Be sure the pre-heating
period
of at least 2 hours is
respected Refrigerant may move between receivers when
refrigerant compressor is stopped and not heated,
especially if stopped for a long time.
This migration may cause liquid shock (slugging) in
valves specially on large dryers containing more
refrigerant