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RS8HP102 © Danfoss 2018-09
AK-CC 750A
Principle
Up to four valves can be connected. One for each solid state
output.
Control can be carried out with electrically operated expansion
valves type AKV, ETS or CCMT.
Or injection can take place with thermostatic expansion valves
(TEV) where the temperature will then be regulated with solenoid
valves type EVR or similar.
If both a stepper valve and a solenoid valve are installed in the
liquid line, any liquid trapped between the two valves will be
returned if the valve is a Danfoss EVR.
Adaptive superheat with AKV (stepper) valve
The evaporating temperature is measured with pressure transmit-
ter P and the superheat with the pressure transmitter and the S2
sensor.
The function contains an adaptive algorithm that independ-
ently adjusts the valve’s opening degree, so that the evaporator
constantly delivers optimum refrigeration at lowest possible
superheat.
The superheat reference will be limited by the settings for min.
and max. superheat.
If the superheat is very low, the valve may be closed very quickly
using the "SH closed" setting.
When the superheat has dropped to 1 K over the "SH closed" limit,
this function will reduce the degree of opening of the valve so
that the valve will with certainty remain closed if the superheat
fall to the "SH closed" value. To ensure that the close function does
not generate the general superheat regulation, the "SH closed"
setting must be at least 1K lower than "SH min".
Flooded evaporator
This function allows liquid flow in the evaporator, but only when a signal
is received. If the signal disappears, then the regulation switches over to
“adaptive superheat”.
Functions:
• Disconnected. Liquid flow is not permitted
• Liquid flow is permitted. Stopped by a common DI signal
• Liquid flow is permitted. Stopped by a signal from the system device. The
signal is common to all sections.
When regulating with a flooded evaporator, three separate superheat
settings are used.
It is the installer’s responsibility to ensure that signal loss to the
controller will not result in liquid throughput to the compressor.
Danfoss accepts no responsibility for damage resulting from
inadequate installation.
Scaling factor for the valve
The valve’s staging area can be limited when a step valve is
chosen or it can be guided using an analogue output signal. The
setting applies to all sections.
Pressure transmitter signal
One pressure transmitter can supply signals to several controllers
if they regulate refrigeration points on the same suction line. But if
a valve is mounted in an evaporator’s suction line, say, a KVP / KVQ
or PM, the pressure transmitter must be placed before the valve.
The signal can now only be used by the relevant controller.
Refrigerant
Before regulation can be commenced, the refrigerant must be
defined.
You can directly select one of the current refrigerants:
1 R12
13
User defined
25 R290
37 R407F
2 R22
14 R32
26 R600
38 R1234ze
3 R134a
15 R227
27 R600a
39 R1234yf
4 R502
16 R401A
28 R744
40 R448A
5 R717
17 R507
29 R1270
41 R449A
6 R13
18 R402A
30 R417A
42 R452A
7 R13b1
19 R404A
31 R422A
8 R23
20 R407C
32 R413A
9 R500
21 R407A
33 R422D
10 R503
22 R407B
34 R427A
11 R114
23 R410A
35 R438A
12 R142b
24 R170
36 R513A
If a new refrigerant is demanded which is not as yet contained
on the list you may select ”User-defined” which is subsequently
set with data for the refrigerant in question. The values can be
ordered from Danfoss.
Warning: Incorrect selection of refrigerant can cause damage to
the compressor.
MOP control
(MOP = Max. Operating Pressure)
The MOP function limits the valve’s degree of opening as long as
the evaporating temperature measured by S1 is higher than the
set MOP temperature. The function can only be active when the
AKV injection valve function is ON.
Start/stop of injection
The injection can be stopped separately for each evaporator sec-
tion.
Liquid injection
SH closed
