98
Capacity
controller RS8ER302 © Danfoss 2016-02
AK-CH
650
Main switch
The main switch is used to stop and start the controlling function.
The switch-over has 2 positions:
- Normal controlling state (Setting = ON)
- Control stopped. (Setting = OFF)
In addition, one can also choose to use a digital input as an
external main switch.
If the switch-over or the external main switch is set at OFF, all the
control’s functions are inactive and an alarm is generated to draw
attention to this – all other alarms cease.
Refrigerant
Before regulation can be commenced, the refrigerant must be
defined.
You can select one of the following refrigerants:
1 R12
12 R142b
23 R410A
34 R427A
2 R22
13
User defined
24 R170
35 R438A
3 R134a
14 R32
25 R290
36 R513A
4 R502
15 R227
26 R600
37 R407F
5 R717
16 R401A
27 R600a
38 R1234ze
6 R13
17 R507
28 R744
39 R1234yf
7 R13b1
18 R402A
29 R1270
40 R448A
8 R23
19 R404A
30 R417A
41 R449A
9 R500
20 R407C
31 R422A
42 R452A
10 R503
21 R407A
32 R413A
11 R114
22 R407B
33 R422D
The refrigerant can only be changed if the “Main switch” is set at
“stopped control”.
Warning: Incorrect selection of refrigerant can cause damage to
the compressor.
Sensor failure
If lack of signal from one of the connected temperature sensors or
pressure transmitters is registered an alarm will be given.
• When there is a S4 and P0 error regulation will continue with 50%
cut-in capacity during day operation and 25% cut-in capacity
during night operation – but minimum one step. (The values
can be set). The relay for "Extra cooling" will be activated in the
event of an error in the control sensor.
• In the case of an S4 error, control continues by suction pressure
P0. This is now with a reference that is 5K under the current
reference for S4.
• When there is a Pc error 100% condenser capacity will be cut in,
but the compressor regulation will remain normal.
• When there is an error on the Sd sensor the safety monitoring of
the discharge gas temperature will be discontinued.
• When there is an error on the Ss sensor the monitoring of the
superheat on the suction line will be discontinued.
• When there is an error on the outdoor temperature sensor
Sc3 the “FDD” function will cease. Regulation with variable
condensing pressure reference cannot either be carried out.
Instead you use the PC ref. min. value as reference.
• S7 error: See page 93.
NB: An incorrect sensor must be in order for 10 minutes before the
sensor alarm deactivates.
Sensor calibration:
The input signal from all connected sensors can be corrected. A
correction will only be necessary if the sensor cable is long and
has a small cross-sectional area. All displays and functions will
reflect the corrected value.
Clock function
The controller contains a clock function.
The clock function is used only to change between day/night.
The year, month, date, hour and minutes must be set.
Note: If the controller is not equipped with a RTC module
(AK-OB 101A) the clock must be reset after each mains voltage
outage.
If the controller is connected to an installation with an AKA-
gateway or an AK system manager, this will automatically reset
the clock function.
Alarms and messages
In connection with the controller’s functions, there are a number
of alarms and messages that become visible in cases of fault or
erroneous operation.
Alarm history:
The controller contains an alarm history (log) that contains all
active alarms as well as the last 40 historical alarms. In the alarm
history you can see when the alarm began and when it stopped.
In addition, one can see the priority of each alarm as well as when
the alarm has been acknowledged and by which user.
Alarm priority:
Differentiation is made between important and not-so-important
information. The importance – or priority – is set for some alarms
whilst others can be changed voluntarily (this change can only
be done with attachment of AK-ST service tool software to the
system and settings must be made in each individual controller).
The setting decides which sorting / action must be carried out
when an alarm is sounded.
• “High” is the most important
• “Log only” is the lowest
• “Interrupted” results in no action
Alarm relay
One can also choose whether one requires an alarm output on
the controller as a local alarm indication. For this alarm relay it is
possible to define on which alarm priority it must react to – one
can choose between the following:
• “Non” – no alarm relay is used
• “High’ – Alarm relay is activated only with alarms with high
priority
• “Low - High’ – Alarm relay is activated only with alarms with “low”
priority, “medium” or “high” priority.
Miscellaneous
