Danfoss Condensing units Service guide
Fitters’ Notes Condensing units
Contents Page
General information on operating Danfoss condensing units ....................................... 3
Equipment conguration .......................................................................... 3
Power supply and electrical equipment ........................................................ 3
Hermetic compressors ............................................................................. 4
Condensers and fans .............................................................................. 4
Stop valves ........................................................................................ 4
Receiver Pressure container ordinance ............................................................. 5
Terminal box ...................................................................................... 5
Safety pressure monitors .......................................................................... 5
Setup ............................................................................................. 5
Protective weather-proof housing .............................................................. 6
Careful installation ................................................................................ 6
Contamination and foreign particles ........................................................... 6
Doing the pipe work ........................................................................... 6
Tubing layout of the condensing units with 1-cylinder compressors
types TL, FR, NL, SC and SC-TWIN ........................................................... 6
Tubing layout of the condensing units with hermetic Maneurop®
reciprocating piston compressors, 1-2-4 cylinder ............................................ 8
Leak check .................................................................................... 8
Soldering ..................................................................................... 9
Protective gas ................................................................................. 9
Evacuating and lling ............................................................................ 10
Exceeding the max. allowable operational lling capacity and setting up outdoors .................11
General information: ......................................................................... 11
“Pump-down” .................................................................................... 13
Max. allowable temperatures ..................................................................... 14
DKRCC.PF.000.G3.02 / 520H6471
Condensing
units
1
Notes
2
Fitters’ Notes Condensing units
General information
on operating Danfoss
condensing units
In the following you will nd general information
and practical tips for using Danfoss condensing
units. Danfoss condensing units represent
an integrated range of units with Danfoss
reciprocating piston compressors. The versions
and con gurations of this series correspond
to the requirements of the market. To give
an overview of the program, the individual
subsections are generally divided into the
various hermetic compressors mounted on the
condensing units.
Condensing units with 1-cylinder compressors
(types TL, FR, NL, GS, SC and SC-TWIN).
Condensing units with hermetic 1 -2 and 4
cylinder Maneurop® reciprocating piston
compressors MTZ, NTZ and MPZ.
Equipment con guration Danfoss condensing units are delivered with a
compressor and condenser mounted on rails
or a base plate. Terminal boxes are prewired. In
addition, stop valves, solder adaptors, collectors,
dual pressure switches and power cables with
3-pin grounded plugs complete the delivery kit.
Power supply and
electrical equipment
Condensing units with 1-cylinder compressors
(types TL, FR, NL, GS, SC and SC-TWIN)
These condensing units are equipped with
hermetic compressors and fans for 230 V 1-,
50 Hz power supply.
The compressors are equipped with an HST
starting device consisting of a starting relay
and a starting capacitor. The components can
also be delivered as spare parts.
The starting capacitor is designed for short
activation cycles (1.7% ED). In practice, this
means that the compressors can perform up
to 10 starts per hour with an activation duration of 6 seconds.
Please consult the corresponding Danfoss
documentation or the current price list for
details and ordering numbers. The Danfoss sales
company responsible for your area will be glad
to help you make your selection.
Condensing units with hermetic 1-2 and
4 cylinder Maneurop® reciprocating piston
compressors MTZ and NTZ.
These condensing units are equipped with
hermetic compressors and fan(s) for di erent
voltage supplies:
• 400 V-3ph-50 Hz for compressor and for
fan(s).
• 400 V-3ph-50Hz for compressor and
230 V-1ph-50Hz for fan(s) (the capacitor(s)
of the fans are included inside the electrical
box).
• 230 V-3ph-50Hz for compressor and
230 V-1ph-50Hz for fan(s) (the capacitor(s)
of the fans are included inside the electrical
box).
• 230 V-1ph-50Hz for compressor (the starting
device (capcitors, relay) is included into the
electrical box) and 230V-1ph-50Hz for fan(s)
Condensing
units
The starting current of the Maneurop® threephase compressor can be reduced through the
use of a soft starter. CI-tronic
TM
soft start, type
MCI-C is recommended for use with this type of
compressor. The starting current can be reduced
up to 40% depending on the compressor model
and the model of soft start used. The mechanical
load that occurs at start-up is also reduced,
which increases the lifespan of the internal
components.
For details on the CI-tronic
TM
MCI-C soft start,
please contact your local Danfoss dealer.
The number of compressor starts is limited
to 12 per hour in normal conditions. Pressure
equalisation is recommended when MCI-C is
used.
3DKRCC.PF.000.G3.02 / 520H6471
Fitters’ Notes Condensing units
Hermetic compressors The hermetically sealed compressor types w,
FR, NL, GS, SC and SC TWIN have a built-in
winding protector. When the protector is
activated, a switch-o time of up to 45 minutes can
occur as the result of heat storage in the motor.
The single-phase Maneurop® compressors
MTZ and NTZ are internally protected by a
temperature/current sensing bimetallic protector,
which senses the main and start winding currents
and also the winding temperature.
The three-phase Maneurop® reciprocating piston
compressors MTZ and NTZ are equipped against
over-current and over-temperature by internal
motor protection. The motor protection is located
in the star point of the windings and opens all
3 phases simultaneously via a bimetallic disk.
After the compressor has switched o via the bimetallic disc, reactivation can take up to 3 hours.
Condensers and fans Highly eective condensers allow a broader
range of usage at higher ambient temperatures.
One or two fan motors are used per condensing
unit depending on the output value.
In addition, the fans can be equipped, e.g. with
a Danfoss Saginomiya fan speed regulator, type
RGE. This allows good condensing pressure
control and reduces the noise level. The fans
are provided with self-lubricating bearings,
which ensures many years of maintenance-free
operation.
If the motor does not work, you can determine by
means of resistance measurement whether the
cause is a switched o winding protection switch
or a possible broken winding.
Stop valves Danfoss condensing units are provided with stop
valves on the suction and liquid side.
The stop valves of the condensing units with
the 1-cylinder compressors (types TL, FR, NL,
GS, SC and SC TWIN) are closed by turning the
spindle clockwise to te soldered piece. This opens
the ow between the pressure gauge connection
and the are connection. If you turn the spindle
counter-clockwise to the rear stop, the pressure
gauge connection is closed. The ow between
the soldered and the are connection is free. In
the centre position, the ow through the three
connections is free. The accompanying soldered
adapters help prevent are connections and to
make the system hermetic.
The stop valves of the condensing units with
Maneurop® reciprocating piston compressors
MTZ and NTZ are directly tted into the suction
and discharge rotalock ports of the compressor
and on the receiver. The suction valve is provided
with long, straight tube pieces in such a manner
that soldered connections can be carried out
without disassembling the Rotalock valve.
4 DKRCC.PF.000.G3.02 / 520H6471
Fitters’ Notes Condensing units
Receiver Liquid receiver is standard on Danfoss
condensing units for use with expansion valves.
The expansion valve is regulating the level in
the receiver buer (the de- or increasing ow
of the refrigerant). The receivers from an internal
volume of 3 l onwards are equipped with a
Rotolock Valve.
Terminal box The Danfoss condensing units are electrically
pre-wired and equipped with a terminal box.
Thus the power supply and additional electrical
wiring can be easily tted. The terminal box of
the condensing units with Maneurop®
compressors is equipped with screw type
connector blocks for both power and controls.
Safety pressure monitors Danfoss condensing units can be ordered
with safety pressure switches KP 17 (W, B…).
Condensing units that do not come equipped
with pressure switches from the factory must
be equipped with a pressure switch at least
the high-pressure side in systems with
thermostatic expansion valves as per EN 378.
The electrical connections of each component
(compressor, fan(s), PTC, pressure switch) are
centralised into this box. A wiring diagram is
available in the cover of the electrical box.
These terminal boxes are protected to a degree
of IP 54.
LP
Start
Stop
AB
Diff.
Setup
HP
Stop
Start
AB
Diff.
The following settings are recommended:
Refrigerant Low pressure side High pressure side
Cut in (bar) Cut o (bar) Cut in (bar) Cut o (bar)
R407C 2 1 21 25
R404A/R507 MBP 1.2 0.5 24 28
R404A/R507 LBP 1 0.1 24 28
R134a 1.2 0.4 14 18
Danfoss condensing units must be set up in a
well ventilated location.
You must ensure that there is sucient fresh air
for the condenser at the intake end.
In addition, you must ensure that no cross-ow
The ventilator motor is connected in such a way
that the air is drawn in via the condenser in the
direction of the compressor.
For optimal operation of the condensing unit,
the condenser must be cleaned regularly.
occurs between the fresh air and the exhaust air.
Condensing
units
5DKRCC.PF.000.G3.02 / 520H6471
Fitters’ Notes Condensing units
Protective weather-proof
housing
Careful installation
Contamination and
foreign particles
Danfoss condensing units that are set up
outside must be provided with a protective
roof or with protective weather-resistant
housing. The scope of delivery includes
optional, high-quality protective weatherproof housings.
More and more commercial cooling and
air-conditioning systems are installed with
condensing units that are equipped with
Contamination and foreign particles are among
the most frequent causes that negatively impact
the reliability and lifespan of cooling systems.
During the installation, the following types of
contamination can enter the system:
Scaling during soldering (oxidations)
Flux residue from soldering
Humidity and outside gasses
Shavings and copper residues from deburring
the tubing
hermetic compressors. High demands are put
on the quality of the installation work and the
alignment of such a cooling system.
Doing the pipe work
Tubing layout of the
condensing units with
1-cylinder compressors
(types GS, TL, FR, NL, SC
and SC-TWIN)
For this reason, Danfoss recommends the
following precautions:
Use only clean and dry copper tubing and
components that satisfy standard DIN 8964.
Danfoss oers a comprehensive and integral
range of products for the necessary cooling
automation. Please contact your Danfoss
dealer for additional information.
When laying the tubing, you should try to make
the shortest and most compact pipe work
possible. Low-lying areas (oil traps), where oil
might accumulate should be avoided.
1. Condensing unit and evaporator are
located on the same level.
The suction line should be arranged slightly
downward from the compressor. The max.
permissible distance between the condensing
unit and the cooling position (evaporator) is
30 m.
TL 8 6
FR 10 6
NL 10 6
SC 10 8
GS 12/16 10
SC-TWIN 16 10
Evaporator
Suction Line Liquid Line
Diameter copper pipe [mm]
Condenser
Compressor
6 DKRCC.PF.000.G3.02 / 520H6471
Fitters’ Notes Condensing units
Tubing layout of the
condensing units with
1-cylinder compressors
(types TL, FR, NL,SC, GS and
SC-TWIN) (continued)
To ensure the oil return, the following crosssections are recommended for the intake and
liquid lines:
2. The condensing unit is arranged above the
evaporator.
The ideal height dierence between the
condensing unit and the evaporator position
is a max. of 5 m. The tube length between
the condensing unit and the evaporator
should not exceed 30 m. The suction lines
must be laid out with double arcs in the form
of oil traps above and below. This is done
using a U-shaped arc at the lower end and a
P-shaped arc at the upper end of the vertical
riser. The max. distance between the arcs is
1 to 1.5 m. To ensure the oil return, the
following pipe diameters are recommended
for the suction and liquid lines:
Suction Line Liquid Line
Diameter copper pipe [mm]
TL 8 6
FR 10 6
NL 10 6
SC 12/15 10 8
All other SCs 12 8
GS 16 10
SC TWIN 16 10
3. The condensing unit is arranged under the
evaporator.
The ideal height dierence between the
condensing unit and the evaporator is a max.
of 5 m. The tube length between the
Evaporator
condensing unit and the evaporator should
not exceed 30 m. The suction lines must be
laid out with double arcs in the form of oil
traps above and below. This is done using a
U-shaped arc at the lower end and a P-shaped
arc at the upper end of the vertical riser. The
max. distance between the arcs is 1 to 1.5 m.
To ensure the oil return, the following pipe
diameters are recommended for the suction
and liquid lines:
Suction Line Liquid Line
Diameter copper pipe [mm]
TL 8 6
FR 10 6
NL 10 6
SC 12 8
GS 16 10
SC TWIN 16 10
Condenser
Compressor
Condensing
units
7DKRCC.PF.000.G3.02 / 520H6471
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