OMEGA AIR RDP 20-1900 Operating instructions

Troubleshooting
Refrigeration Dryer Series RDP 20 - 1900

1 Troubleshooting
Troubleshooting and maintenance procedures can only be performed by qualified personnel with
the necessary knowledge.
Before any maintenance or service parts make sure that:
-no part or device is powered and must not be connected to a power source
-that no part or device is under pressure and must not be connected to a compressed air
system under pressure,
-that the maintenance staff fully and accurately read the operating instructions, and in
particular the chapters relating to safety at work.
SYMPTOM
POSSIBLE CAUSE - PROPOSED COURSE OF ACTION
None of the LED lights on
the controller are on
*controller
● Make sure that the system is connected to a power source.
● Check the electrical installation (internal and external).
● Check that the circuit board is not damaged.
The TEST button is
pressed, but
the condensate is not
drained
*condensate drain
● The service valve in front of the drain is closed - open it.
● The dryer is not pressurized - set normal operating conditions.
● The solenoid valve is defective - replace the condensate separator.
● The circuit board is damaged - replace the condensate drain.
Condensate is only
drained when the TEST
button is pressed.
*condensate drain
● The capacitive sensor is dirty - open the condensate separator and
clean the plastic tube of the sensor.
The spout blows out air.
*condensate drain
● The electromagnetic valve diaphragm is dirty - open the drain and
clean it.
● The capacitive sensor is dirty - open the condensate separator and
clean the plastic tube of the sensor.
The drain is in a state of
alarm/doesn’t work at all.
*condensate drain
● The capacitive sensor is dirty - open the condensate separator and
clean the plastic tube of the sensor.
● The service valve in front of the drain is closed - open it.
● The dryer is not pressurized - set normal operating conditions.
● The solenoid valve is defective - replace the condensate separator.
● if the controller was replaced, it may be necessary to change the
controller parameters (parameter “2”to be set on value “0”) –see
section 2.3
Errors “Pf1”, “Pf2”, ”Pf3”
are shown on controller
*controller
*sensor
● Pf1 - dew point sensor
● Pf2 - compressor sensor
● Pf3 - condenser sensor
● A sensor is missing or is badly/incorrectly installed – check the sensor
wiring on the controller
● The controller is faulty/not working properly –the controller has to
be replaced

Error “Lt” is shown on
controller
*controller
* sensor
● Lt error occurs when dew point temperature value drops below -2°C
● Bypass valve is not set properly – unscrew the protection cap and
tighten the nub in a counter clockwise fashion for 1 full turn (360°),
wait if dew point values are raising, if not repeat process
● May occur if the ambient temperature is to low
Error “Cln” is shown on
controller
*controller
* sensor
● Cln error occurs when the temperature on the condenser surpasses
70°C
● May occur if the ambient temperature is too high
●May occur if condenser coil is dirty –please clean the condenser coil.
● May occur if the fan is not working (there is no ambient airflow
through the dryer) - please check the electrical wiring of the fan.
● May occur if there is a bad connection of temperature sensor Ntc.
Cond. to the controller –check if the connection of condenser
temperature sensor is good.
Error ”Ht” is shown on
controller
*controller
*sensor
● Ht error occurs when the temperature of compressor surpasses
110°C
● Check the copper tubing for any leakage –there may very well be a
leakage and the temperature goes above 110°C due to insufficient
coolant in the system
High dew point
temperature shown on
controller (E.g. >5°C)
*controller
*sensor
*bypass
*copper tubing
● Check if sensor is installed correctly (placed in the insulated tubing on
evaporator inlet) –adjust the placement of sensor if needed
● Bypass valve is not set properly – unscrew the protection cap and
tighten the nub in a clockwise fashion for 1 full turn (360°), wait if dew
point values are lowering, if not repeat process
● There could be a leakage of coolant in the system – of possible check
the pressure of the dryer on service valves
● May occur if the ambient temperature is too high
Fan on condenser does
not work
*fan
*controller
● Check the electrical wiring of the fan
● Check the output voltage for fan on the controller
● Check the working of the fan itself (connect it to an external power
supply)
Dryer does not start
*controller
*sensor
*bypass
*copper tubing
● Check the electrical installation (internal and external).
● Check if the controller is malfunctioning (E.g. is there output voltage
on the controller pins after start up time has elapsed)
● Check if there are not safety switches (high and low pressure) active
(this applies for first dryer start after it has been installed)
● If the dryer is 3 phase powered, check if the phase sequence is
correct
● There could be leakage of coolant in the system – of possible check
the pressure of the dryer on service valves
* part/category with issue
NOTE: When the condensate drain is in alarm condition, the solenoid valve will open every 7
minutes for 7.5 seconds

2 Controller RDC 2
At startup, the controller shows the time remaining until compressors starts by displaying COMP TIME
X MIN. The value X can be changed by changing the parameter no. 5.
After the countdown is finished, the controller RDC 2 shows the temperature of the dew point reached
by the refrigeration air dryer in the normal operation. By pressing the UP (▲) button, the outlet
temperature of the compressor is displayed. By pressing the DOWN (▼) button, the condensation
temperature is displayed (the temperature sensor is connected) or the condensation pressure is
displayed (the pressure sensor is connected). In case of fault, an alarm will appear on the display. The
alarm automatically turns off when the dryer is restarted and is operating properly.
a) Sensors used for regulation:
1) Tdew = Dew point temperature
2) Tcomp = Compressor temperature
3) Tcond ali pcond = Condensation temperature or pressure (4-20 mA)
b) Regulated components:
1) Fan (ON/OFF)
•Fan symbol is displayed when in ON state
2) Compressor (ON/OFF)
•Compressor symbol is displayed when in ON state
3) Drain (ON/OFF)
•Drain symbol is displayed when in ON state
c) Operation of fan and compressor
1) Normal operation:
•The compressor is always running
•The fan is regulated based on measured condensation temperature or pressure
•Dew point temperature is displayed.
2) Alarm operation
•In alarm state the normal operation is overridden.
•If more alarms are activated the last one activated has priority with display and
fan/compressor operation. All other active alarms have to be resolved before
continuing in normal operation.
•Alarm is displayed.

2.1 Electric scheme RDC 2
The controller has 3 outputs (230 V), for compressor, fan and drain. The other outputs are for alarm.
The alarm is triggered via opto triac, which can handle 600VAC/50mA.
Controller can also be turned OFF/ON via In. Remote. When the current flows, the controller goes to
OFF state, when the circuit is disconnected, the controller is in ON state. (See the attached scheme
above).
For the MODBUS communication, the twisted pair cable needs to be screwed to the A and B terminals.
To communicate with the PC, an adapter is needed. The address for the MODBUS communication is 1.

2.2 RDC 2 parameters
Parameter
number
Parameter
name
Allowed to
change
Press UP
Press
DOWN
Default
1
Drain Cycle
Value
yes
Increase
value
Decrease
value
1
2
Drain Period
Value
yes
Increase
value
Decrease
value
200 sec
3
CondSensorType
no (unless
sensor type
not NTC)
Increase
value
Decrease
value
0
4
no
Increase
value
Decrease
value
5
5
Min Compressor
OFF time
yes
Increase
value
Decrease
value
1 min
6
no
Increase
value
Decrease
value
2
7
no
Increase
value
Decrease
value
5
8
no
Increase
value
Decrease
value
0
9
no
Increase
value
Decrease
value
0
10
no
Increase
value
Decrease
value
0
11
no
Increase
value
Decrease
value
40.0
12
no
Increase
value
Decrease
value
39.5
13
Remote Control
yes
Increase
value
Decrease
value
0
14
MOD BUS
Address
yes
Increase
value
Decrease
value
1
15
no
Increase
value
Decrease
value
365

2.3 RDC 2 parameter settings
In the following paragraph, a procedure to change the minimal compressor OFF time is shown.
To change the minimal compressor OFF time, you must choose programming parameter no. 5 and
change the value from default to the desired value. To do that you must:
•Hold SET button for 3 seconds
•Enter password (000) (press SET 3 times)
•Continue pressing SET button until you reach parameter number 5
•You will see the default parameter value (1 min). Change it to a desired value if necessary, if
not skip the next step
•Wait a couple of seconds, the controller exits automatically
Turn off the dryer and then turn it back on.
Every other parameter can be changed by similar procedure. Differences are in parameter number and
in parameter value.
To reset the parameters in the WORKING status, you must first hold SET+UP for 3 seconds and you
move to STANDBY status. When in STANDBY status, you can reset the parameters to default values
by holding UP+DOWN for 3 seconds.

2.4 RDC 2 MODBUS communication
ADDRESS
NAME
TYPE
VARIABLE X
UNIT
40013
ADDRESS
RDWR
Address = X
40014
Service Time
R_ONLY
Service Time = X
day
40015
No. of alarms in last 24h
R_ONLY
Alarm 24 H Number= X
40016
No. of alarms since service
R_ONLY
Total Alarms = X
40017
Days Between Maintenance
R_ONLY
Days after Service = X
40018
Output Compressor Status
R_ONLY
0= Comp. OFF 1= Comp. ON
40019
Output Fan Status
R_ONLY
0= Fan OFF 1= Fan ON
40020
Output Drain Status
R_ONLY
0= Drain OFF 1= Drain ON
40021
Output Alarm Status
R_ONLY
0= Alarm OFF 1= Alarm ON
40022
T_Dew
R_ONLY
T_Dew = (X-200)/10
°C
40023
T_Comp
R_ONLY
T_Comp = (X-200)/10
°C
40024
T_Cond
R_ONLY
T_Cond = (X-200)/10
°C
40025
P_Cond
R_ONLY
P_Cond = X/10
Bar
40026
Digital Input status
R_ONLY
0= contact open 1 = contact close
40027
Buttons
R_ONLY
0= no switches 1= SET
2=UP 3= SET & UP
4= DOWN 5= SET & DOWN
6= UP & DOWN
7= SET & UP & DOWN
40028
Alarm CLn Status
R_ONLY
0=no alarm 1 = alarm active
40029
Alarm Lt Status
R_ONLY
0=no alarm 1 = alarm active
40030
Alarm Ht status
R_ONLY
0=no alarm 1 = alarm active
40031
Alarm PF1 Status
R_ONLY
0=no alarm 1 = alarm active
40032
Alarm PF2
R_ONLY
0=no alarm 1 = alarm active
40033
Alarm PF3
R_ONLY
0=no alarm 1 = alarm active
40034
Controller Status
R_ONLY
0= STANDBY 1=NORMAL
OPERATION 2=PROGRAMMING
MODE 3=ALARM MODE
4= TESTING MODE

3 Hot gas bypass valve
The hot gas bypass valve injects a portion of the hot gases (taken from the compressor outlet) into
the tube between the evaporator and the suction side of the compressor, thereby maintaining a
constant temperature of the evaporator at about 1-2 ° C. This injection prevents the formation of ice
in the evaporator of the dryer under any load conditions. You can set it under no-load conditions
(you have to close it to reduce the temperature on the controller to approximately 1-2 °C). To do this
the cap has to be unscrewed and then the valve turned in direction of “-”according to the image
below. Please give it some time (10 - 20 min) before finishing the setting. A good initial rotation
would be 180 °.
Below you see a schematic of a bypass valve.
2: RDP 20 - 480
1: RDP 480 - 2600

4 Spare parts
DESCRIPTION
PART
NUMBER
RDP
20
35
50
75
100
140
180
235
300
380
480
600
750
950
1150
1300
1500
1900
2600
Compressor
1401365
1
1
1
1401437
1
1401431
1
1
1401369
1
1401439
1
1401440
1
1
1401441
1
1
1401374
1
1401375
1
1
1401376
1
1
1401410
1
1401421
1
Fan & Condenser pack
2101729
1
1
1
2101700
1
2
2101701
1
1
2
2
2101732
1
1
2101802
2
2
Condenser
2101822
1
1
2101839
1
1
1
2101855
1
Fan
1101981
1
Fan motor
2101864
1
1
1
1
1
Fan blade
2101865
1
1
1
1
1
Fan diffuser
2101863
1
1
1
1
1
Hot gas by-pass valve
2204737
1
1
1
1
1
1
1
1
2204746
1
1
2204736
1
1
2204748
1
1
1
2204749
1
1
1
Expansion valve
2204771
1
Expansion valve connector
2204773
1
Filter
2101578
1
1
1
1
2100441
1
1
2100597
1
1
2101609
1
1
2300921
1
1
1
1
2300922
1
1
1
1
2300925
1
Fan regulation pressure switch
3001095
1
1
1
1
1
1
1
1
1
1
1
1
High pressure switch
3001154
1
1
1
1
1
1
1
Low pressure switch
3001111
1
1
1
1
1
1
1
RDC 2 Controller
2101826
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Pressure transducer PP011
2101898
1
PT1000 probe PMT6-67
3000857
1
XEV 22 D Dixell Driver
2101897
1
NTC temperature probe 1m
4001120
3
3
3
3
3
3
3
3
3
3
3
3
NTC temperature probe 2m
4001141
3
3
3
3
3
3
3
Main 1 - phase Switch
1219579
1
1
1
1
1
1
1
1
1
1
1
1
Main 3 - phase Switch
3001135
1
1
1
1
1
1
3001156
1
Main 3 - phase Switch - handle
3001136
1
1
1
1
1
1
1
Electronic drain
321900860
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1 - phase circuit breaker
3003681
1
1
1
1
1
1
1
3- phase circuit breaker
3003715
1
1
1
1
1
1
3003713
1
Phase protection relay
3003527
1
Contactor
3001134
1
1
1
1
1
1
3001162
1
Motor protection
3003680
1
3003682
1
1
1
3003683
1
1
3003695
1
3003699
1
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