Caution for work
1. Charge in liquid phase after breaking the vacuum at 7 or 10 bar.
2. Confirm that it is contained in a cylinder special to R744 (CO2).
3. Use the manifold valve and the charge hose special to R744 (CO
2
).
4. Show a warning sign board stating “High pressure gas charge” at a place where it can be seen by people. (When the charging place
can be approached from more than one place, show the board at respective places.)
5. Even when the charge pressure dropped in the cylinder, never heat the cylinder higher than 40°C for reason of security.
6. Do not lay flat the cylinder during charging.
7. Before disconnecting the charge hose, open the blow valve of gauge manifold to release CO
2
refrigerant. Take care to prevent
frostbite because the liquid refrigerant may be released.
Note on R744 (CO
2
) :
R744 (CO
2
) uses pressures higher than equipment based on Freon. Sufficient care must be taken when charging the gas.
5. System design recommendations
List of external output
Name
Purpose (Factory default)
Specifications
Point of caution
External
input
CNS1(Green)
no use
Non-voltage contact
(DC12V)
Stops when open.
CNS2(Red)
ON-OFF SW
Valid when short-circuited.
CNS3(Brown)
Compulsory oil return control input
Valid when short-circuited.
Use connectors fixed with
tapes on the outer wall of the
control box.
CNG1(Blue)
Gas cooler fan snow control input
Valid when short-circuited
CNG2(White)
Multistep demand input
Valid when short-circuited.
External
output
CNH(Blue)
Operation output
12 VDC
output
(10 mA)
-
CNY(White)
Error output
-
CN
NZ1, CNZ2
(Red) (Black)
Set with 7-segment (*)
(Molex: Provide 5557-2R, 5556T at site.)
(*)
0
: Operation output
1
: Error output
2
: Compressor ON output
3
: Fan ON output
4
: Oil return operation output
5
: High pressure control output
6
: Compressor operation time (Maintenance time) time-over output
For the default output, see Instruction manual page 48
5.7 External signal output
Part of operating states can be output from the controller of condensing unit.
1. Alarm signal
:
If the condensing unit stops under abnormal condition, an alarm signal is released.
2. Compressor operation signal
:
Signals of compressor operation and stop can be extracted.
- Extract signals via a relay.
Where the power for the relay contacts is taken from a terminal box, connect the wires as shown by the electric wiring in the next section.
Fig. 29
Middle
pressure side
service port
Low
pressure side
service port
42
AB408540130380en-000102
© Danfoss | Climate Solutions | 2023.02
Application Guidelines
