Danfoss EKC 361 User Manual page 12

Start of controller
When the electric wires have been connected to the controller,
the following points have to be attended to before the regulation
starts:
1. Switch off the external ON/OFF switch that starts and stops the
regulation.
2. Follow the menu survey on page 7, and set the various para-
meters to the required values.
3. Switch on the external ON/OFF switch, and regulation will start.
If the temperature fluctuates
When the refrigerating system has been made to work steadily,
the controller's factory-set control parameters should in most
cases provide a stable and relatively fast regulating system.
If the system on the other hand oscillates, you must register the
periods of oscillation and compare them with the set integration
time T , and then make a couple of adjustments in the indicated
n
parameters.
Trouble shooting - ICS/PM with CVQ
In addition to the error messages transmitted by the controller,
the table below may help identifying errors and defects.
Symptom
Media temperature too low.
Actuator feels cold.
Media temperature too low.
Actuator fells warm.
Media temperature too high.
Actuator feels cold.
Media temperature too high.
Actuator feels warm.
12
Defect
Short-circuited NTC resistor in
actuator.
Defective PTC resistor (heating
element) in actuator.
Undersized cable to CVQ.
Undersized 24 V transformer.
Loss of charge in actuator.
Fault in refrigerant plant.
Cut out NTC resistor in actuator.
Manual RS8AE802 © Danfoss 12-2009
4. If the system has been fitted with a thermostatic expansion
valve, it must be set to minimum stable superheating. (If a
specific T0 is required for the adjustment of the ex pansion valve,
the two setting values for the actuator temperature (n01 and
n02) can be set to the belonging value while the adjustment
of the expansion valve is carried out. Remember to reset the
values).
5. Follow the actual room temperature on the display. (On
terminals 2 and 5 a current signal can be transmitted which
represents the room temperature. Connect a data collection
unit, if applicable, so that the temperature performance can be
followed).
If the time of oscillation is longer than the integration time:
(T > T , (T is, say, 4 minutes))
p n n
1. Increase T to 1.2 times T
n
2. Wait until the system is in balance again
3. If there is still oscillation, reduce K
4. Wait until the system is in balance
5. If it continues to oscillate, repeat 3 and 4
If the time of oscillation is shorter than the integration time:
(T < T , (T is, say, 4 minutes))
p n n
1. Reduce K by, say, 20% of the scale reading
p
2. Wait until the system is in balance
3. If it continues to oscillate, repeat 1 and 2
Confirmation of defect
If less than 100 ohm is measured across terminals 17 and 18 (disassemble the lead),
the NTC or the leads are short-circuited. Check the leads.
If more than 30 ohm or 0 ohm is measured across terminal 23 and 24 (disassemble
the lead), either the PTC or the leads are defective.
Check the leads.
Measure voltage across terminanls 77 and 78 (min. 18 V a.c.).
Measure resistance in power cables to CVQ (max. 2 ohm)
Measue voltage across transformer output terminals (24 V a.c. +10/ -15%) under all
working conditions.
If voltage drops under some working conditions the transformer is undersized.
Replace actuator.
Examine platn for ther defects.
If more than 200 kohm is measured across terminals 17 and 18 (disassemble the
lead), either the NTC or leads are disconnected.
Check the leads.
p
by, say, 20%
p
EKC 361