PRODUCT INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATIONGENERAL INFORMATION
Danfoss PSH019 to 039 compressors are
designed and manufactured according to the
state of the art and to valid European and US
regulations. Particular emphasis has been placed
on safety and reliability. Related instructions are
highlighted with the following icons:
This icon indicates instructions to avoid
safety risk.
R
This icon indicates instructions to avoid
reliability risk.
The purpose of this guideline is to help
customers qualify compressors in the unit.
You are strongly advise to follow these
instructions. For any deviation from the
guidelines, please contact Danfoss Technical
Support. In any case, Danfoss accepts no
liability as a result of the improper integration
of the compressor into the unit by the system
manufacturer.
4AB232986440751en-001301
Features
Overview
Danfoss PSH019 to 039 compressor is optimized
for heat pump application. Moreover, it benefits
from an improved design to achieve the highest
efficiency and increased life time.
New PTFE spring seal for even lower
leaks
Heat shield that lower the heat
transfer between discharge and
suction gas and the acoustic level
Pre-assembled liquid injection valve
and injection channel
R410A heating optimized and
dedicated scroll profile
Patented motor cap for optimal
motor cooling and higher resistance
to liquid slugging
GENERAL INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATIONPRODUCT INFORMATION
Lead free polymer bearings improve
behavior under poor lubrication
conditions
Pre-wired electrical box with liquid
injection control board (aka. OCS,
Operating Control System), integrate
below protections:
- Phase sequence/loss
- Over high discharge temperature
- Injection valve shut-off when power
loss by super capacitor
Patented motor centering spacer
Improved lower bearing centering
5AB232986440751en-001301
Features
Liquid injection
GENERAL INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATIONPRODUCT INFORMATION
Danfoss PSH019 to 039 requires liquid injection
to maintain sufficiently low discharge gas
temperature in the operating envelope. The
PSH019 to 039 compressors are provided with a
liquid injection connection.
The compressor’s liquid injection port should
be connected to the system main liquid
line after condenser & filter drier. The liquid
phase refrigerant is directly injected into the
compressor scroll set. Liquid refrigerant vaporize
in the scroll and absorb the heat, result in cooling
down the compressor’s discharge temperature.
A LIV (Liquid Injection Valve) is pre-installed on
the PSH019 to 039 compressor to control the
liquid injection mass flow, keep the constant
compressor discharge gas temperature. The
LIV’s liquid injection regulation is based on the
discharge gas temperature measured via PT1000
temperature sensor located on discharge line.
Considering the distance between PT1000 sensor
and scroll set, the liquid injection is activated
for when discharge temperature exceed 121°C
(250°F) at the measurement point.
A Danfoss PT1000 temperature sensor is supplied
with PSH compressor in the accessory bag.
Customer need attach this sensor on the surface
of discharge pipe with 40mm (1.6inch) away from
the compressor discharge port, the sensor should
be fixed by a metallic collar/clip tube, have good
thermal contact by adding thermal paste and be
insulated from ambient disturbance by thermal
wrap.
PSH019 to 039 compressor’s OCS is equipped
with super capacitor. In case of suddenly loss
the power supply, super capacitor can use its
stored energy to shut-off the LIV. This feature
could secure compressor without having liquid
migration via LIV, mitigate the compressor
failure risk at next time start-up. Thanks to this
feature, liquid injection line solenoid valve is not
mandatory.
A minimum 4K (7.2°F) subcooling is necessary to
ensure correct liquid injection.
6AB232986440751en-001301
Filter drier
Condenser
Discharge T sensor
LIV
Control
Evaporator
EXV
Compressor model designation
Nomenclature
Heat pump
application
Scroll (commercial /
large commercial)
Lubricant
R410A, POE
Heating capacity
in kW at 50Hz
-7°C/50°C/SH5K/SC4K
19.4°F/122°F/SH9°F/7.2°F
Danfoss PSH019 to 039 scroll compressors for
R410A are available as single and manifolding
compressors. The example below presents the
compressor nomenclature which equals to the
technical reference as shown on the compressor
nameplate. Code numbers for ordering are listed
in section “Ordering information”.
DLC4A039SHP
Evolution index
Motor protection type
L: Internal overload protector
Connections
A: simplified bare compressor(without oil
sight glass and oil equalization)
C: full package (including injection valve)
D: bare compressor
Motor voltage code
3: 200-230V/3~/60Hz
4: 380-400V/3~/50Hz - 460V/3~/60Hz
9: 380V/3~/60Hz - 342-418V/3~/60Hz
UL index
GENERAL INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATIONPRODUCT INFORMATION
Vavg = Mean voltage of phases 1, 2, 3
V1-2 = Voltage between phases 1 & 2
Wiring ConnectionsElectrical supply is connected to the compressor
terminals by Ø 4.8mm (3/16") screws. The
maximum tightening torque is 3Nm. Use a ¼"
ring terminal on the power leads. The compressor
must be connected to earth with the 5mm
(0.2inch) earth terminal screw.
The control board comes pre-installed within
the terminal box of full package compressor.
The control board comes with pre-wired liquid
injection valve connection, is used to provide
overheating and possible motor damage. Voltage
imbalance is given by the formula:
V1-3 = Voltage between phases 1 & 3
V2-3 = Voltage between phases 2 & 3
control of liquid injection valve according to
feedback of discharge temperature sensor.
The discharge gas temperature cable must be
plugged to the discharge temperature sensor
installed on discharge tube by customer.
In electrical box, three wires are pre-installed
between terminals and control board to monitor
the phase sequence and phase loss. This could
avoid compressor running at abnormal electrical
supply and protect the compressor.
The control board must be connected to:
• a power supply of the appropriate voltage
(230VAC) with a 2 poles 7.62mm (0.3inch) pitch
terminal block (an independent power supply is
recommended).
• a 1/4" fasten earth connection for 230V supply
models.
Control board power supply
3 phase sequence/loss
protection(pre-wired)
Discharge temperature
LED1 LED2
sensor PT1000
Liquid injection valve
control(pre-wired)
Relay output M1-M2
TTL communication port
Liquid injection valve
control
Plug and unplug connector on board with
electricity is forbidden. Never touch board with
electricity by hand or tool. Cable connected to
control board can not be short circuit or connect
to high voltage.
12AB232986440751en-001301
Electrical data, connections and wiring
Two LED indicators are located on control board
as picture showed above.
LED1 is the control board power supply status
indicator. When the power supply is ON, the LED1
presents GREEN color. LED2 is the protection
status indicator. When there is no alarm, the LED2
presents GREEN color. When there is a alarm, the
LED2 presents YELLOW/RED color blinking code.
More detail blinking code information refer to
related section.
IP RatingThe compressor terminal box according to IEC529 is IP54 for all models when correctly sized IP54 rated
cable glands are used.
First numeral, level of protection against contact and foreign object
5- Dust protected
Second numeral, level of protection against water
4- Protection against water splashing
Terminal box
temperature
The temperature inside the terminal box
R
may not exceed 70°C (158°F). Consequently,
if the compressor is installed in an enclosure,
precautions must be taken to avoid that the
temperature around the compressor and in
the terminal box would rise too much. The
installation of ventilation on the enclosure panels
may be necessary. If not, the control board may
not operate properly. Any compressor damaged
related to this will not be covered by Danfoss
warranty. In the same manner, cables must be
selected in a way to insure that terminal box
temperature does not exceed 70°C (158°F).
GENERAL INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATIONPRODUCT INFORMATION
13AB232986440751en-001301
Electrical data, connections and wiring
Three phase electrical
characteristics
GENERAL INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATIONPRODUCT INFORMATION
Compressor models
Motor code 3
Motor code 4
Motor code 9
LRAMCCMOCWinding resistance
AAAΩ
PSH01920343380.39
PSH02326751500.27
PSH02626761530. 27
PSH03030464560.24
PSH03431569640.22
PSH03935175710.22
PSH0199820191.47
PSH02314223221.05
PSH02614229241.05
PSH03014732280.92
PSH03415833310.83
PSH03919738.6360.83
PSH01912426231.05
PSH02316033260.72
PSH02616035290.72
PSH03016837330.62
PSH03417741370.57
PSH03923951440.57
LRA (Locked Rotor Amp)
MCC (Maximum
Continuous Current)
MOC (Maximum
Operating Current)
Locked Rotor Amp value is the highest average
current as measured on mechanically blocked
compressor tested under nominal voltage. The
LRA value can be used as rough estimation for
The MCC is the current at which the motor
protection trips under maximum load and
low voltage conditions. This MCC value is the
The MOC is the current when the compressors
operates at maximum load conditions and 10%
below nominal voltage. MOC can be used to
select cables and contactors.
the starting current. However in most cases, the
real starting current will be lower. A soft starter
can be applied to reduce starting current (See
section “soft star t”).
maximum at which the compressor can be
operated in transient conditions and out of the
application envelope.
In normal operation, the compressor current
consumption is always less than the MOC value.
14AB232986440751en-001301
Electrical data, connections and wiring
Winding resistance
Motor protection
Phase sequence/loss
protection
Winding resistance is the resistance between
phases at 25°C (77°F) (resistance value +/- 7%).
Winding resistance is generally low and it
requires adapted tools for precise measurement.
Use a digital ohm-meter, a “4 wires” method and
measure under stabilised ambient temperature.
Winding resistance varies strongly with winding
temperature; if the compressor is stabilised at a
different value than 25°C (77°F), the measured
resistance must be corrected with following
formula:
The compressors models PSH019 to 039 have
been provided with an internal overload
protection to prevent against excessive current
and temperature caused by overloading, low
refrigerant flow or phase loss. The cutout current
is the MCC value listed before.
The protector is located in the star point of the
motor and, should it be activated, will cut out all
three phases. It will be reset automatically. While
Use a phase meter to establish the phase
orders and connect line phases L1, L2 and L3
to terminals T1, T2 and T3, respectively. The
compressor will only operate properly in a single
direction, and the motor is wound so that if the
connections are correct, the rotation will also be
correct.
a + t
R
= R
amb
25°C (77°F)
a + t
t
: reference temperature = 25°C (77°F)
25°C (77°F)
t
: temperature during measurement °C(°F)
amb
R
: winding resistance at 25°C (77°F)
25°C (77°F)
R
: winding resistance at tamb
amb
amb
__________
25°C (77°F)
Coefficient a = 234.5
not compulsory, an additional external overload
is still advisable for either alarm or manual reset.
Then it must be set below MCC value:
• When the motor temperature is too high, then
the internal protector will trip.
• When the current is too high the external
overload protection will trip before the internal
protection therefore offering possibility of
manual reset.
determine the cause of the phase problem before
re-energizing the control circuit.
The phase sequence and phase loss monitoring
functions are active during a 5 seconds window
1 second after compressor start-up (power on
L1-L2-L3).
GENERAL INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATIONPRODUCT INFORMATION
R
PSH019 to 039 control board provides protection
against phase reversal and phase loss at startup. Apply the recommended wiring diagram
from the section “Wiring information”. The
circuit should be thoroughly checked in order to
LED2 status displayBlinking sequenceStatus
••••••••••••
••••••••••••
••••••••••••
Continuous onNo alarm
Yellow 2 times/Red 1 time
Yellow 2 times/Red 2 time
The pre-wired lines between compressor
power terminals and control board are NOT
allowed to disconnect! Disconnection of those
pre-wired lines may loss this protection and
cause other function abnormal.
ALARM: Phase loss error
ACTION: Relay output M1-M2 open, compressor
RESET: Power off, power on the OCS board
ALARM: Phase sequence error
ACTION: Relay output M1-M2 open, compressor
RESET: Power off, power on the OCS board
stopped
stopped
15AB232986440751en-001301
Approvals and certificates
Approvals and
certificates
Pressure equipment
GENERAL INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATIONPRODUCT INFORMATION
directive 2014/68/EU
Low voltage directive
2014/35/EU
PSH019 to 039 scroll compressors comply with
the following approvals and certificates.
Maximum allowable pressure (Low side) - Ps33.3 bar(g) (483psig)
Declaration of conformityContact Danfoss
ProductsPSH019 to 039
Declaration of conformity
ref. Low voltage Directive 2014/35/EU
Certificates are listed on the product datasheets:
http://www.danfoss.com/odsg
All PSH models
All 60 Hz PSH models
Contact Danfoss
Machines directive
2006/42/EC
Internal free volume
ProductsPSH019 to 039
Manufacturer's declaration of incorporation
ref. Machines Directive 2006/42/EC
ProductsInternal free volume without oil
PSH01912. 4757
PSH023-026-030-03414. 3873
PSH03914.6891
Contact Danfoss
litrecu.inch
16AB232986440751en-001301
Design piping
General requirementsProper piping practices should be employed to:
1. Ensure adequate oil return, even under
minimum load conditions (refrigerant speed,
piping slopes…). For validation tests see section
“Manage oil in the circuit”.
To condenser
HP
max. 4m
(13ft)
max. 4m
(13ft)
0.5% slope
4m/s (13ft/s)
or more
U-trap, as short as possible
8 to 12m/s
(26 to 40ft/s)
0.5% slope
4m/s (13ft/s)
or more
U trap, as short as possible
LP
Evaporator
2. Avoid condensed liquid refrigerant from
draining back to the compressor when stopped
(discharge piping upper loop). For validation
tests see section “Manage off cycle migration”.
General recommendations are described in the
figures below:
Upper loop
HP
Condenser
LP
3D exibility
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
3. Piping should be designed with adequate
three-dimensional flexibility to avoid excess
vibration. It should not be in contact with the
surrounding structure, unless a proper tubing
mount has been installed. For more information
on noise and vibration, see section on: “Sound
and vibration management”.
17AB232986440751en-001301
Design piping
Tandem Configuration
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
PSH019 to 039 are qualified with even tandem
combination use static system to balance the oil
level between the compressors.
- Tubings, according to specific outline drawings
indicated in the following table.
- Tandem kit.
- Compressors.
By default, PSH tandems are not factory-built. To
complete an assembly in the field, you will need:
Suction
1"3/8 PSH019 tandem
1"5/8 PSH023-039 tandem
Supplied with the compressor
Included in tandem kit
Not supplied
Oil equalisation
1"1/8
1"1/8 PSH019 tandem
1"3/8 PSH023-039 tandem
Tightening torque 100N.M
18AB232986440751en-001301
Design compressor mounting
General requirements
Single requirements
Tandem Kits
Compressors used in single applications must be
mounted with flexible grommets.
Compressors used in parallel applications must
be mounted with rigid spacers onto rails and
Compressor PSH019 to 039 are delivered with
rubber grommets and steel mounting sleeve
used to isolated the compressor from the base
frame.
The grommets must be compressed until contact
between the flat washer and the steel mounting
sleeve is established. The required bolt size for
the PSH019 to 039 compressors is HM8-40. This
bolt must be tightened to a torque of 15Nm.
The compressors must be mounted with rigid
mounting spacers on rails. Rubber grommets and
spacers must be installed below rails.
the manifold assembly must be mounted with
flexible grommets onto the frame.
During operation, the maximum inclination from
the vertical plane must not exceed 3 degrees.
HM 8 bolt
Lock washer
Flat washer
Steel mounting
sleeve
Rubber grommet
Nut
Tightening torque 15 Nm
15 mm
The rigid mounting spacers are included in
tandem accessory kits. The rubber grommets are
supplied with compressor.
For more details about parallel mounting feet,
please see parallel unit outline drawing.
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
Not supplied
Φ8x75mm
0.31x2.95inch
Tightening
torque
15Nm
4mm
(0.16inch)
thickness
Supplied with the compressor
Included in tandem kit
Not supplied
Tightening
torque
15Nm
19AB232986440751en-001301
Manage oil in the circuit
Requirement
System evaluation
R
Oil level must be visible or full in the sight
glass when the compressor is running and when
all compressors of the circuit are stopped.
Single compressorManifold compressors
Non splitTes t N °1Tes t N° 1+2
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
Test, criteria and solutions
Tes t N °PurposeTest conditionsPass criteriaSolutions
1
2
Check proper
oil return
Check oil
balancing
SplitTe st N °1+3Test N° 1+2+3
A
Lowest foreseeable evaporation,
and highest foreseeable
condensation.
Minimum number of compressor
running for 6 hours.
For reversible system, perform test
in both heating and cooling mode.
A
Lowest foreseeable evaporation,
and highest foreseeable
condensation.
All compressor running for 6
hours.
For reversible system, perform test
in both heating and cooling mode.
Oil level must be visible or full in the
sight glass when the compressor is
running and when all compressors
of the circuit are stopped.
Oil level must be visible or full
in the sight glass when the
compressors are running and when
all compressors of the circuit are
stopped
1. Top-up with oil, generally 3% of
the total system refrigerant charge
(in weight). Above 3% look for
potential oil trap in the system.
2. Integrate a function in control
logic to run all compressors
simultaneously in order to boost oil
return (for more details see section
“Control Logic”)
3. Oil separator can be added
1. Top-up with oil, generally 3% of
the total system refrigerant charge
(in weight).
2. Check that manifold piping is
conform to Danfoss requirements.
3. Integrate a function in control
logic to stop manifold periodically in
order to balance oil (for more details
see section “Control Logic”)
3
Oil return in
split systems
20AB232986440751en-001301
Since each installation is unique,
test 1 and 2 can not fully validate
the oil return. Oil level must
be checked and adjusted at
commissioning.
Oil level must be visible or full in the
sight glass when the compressor is
running and when all compressors
of the circuit are stopped.
1. Pay special attention to “Piping
design”
2. Oil separator is strongly
recommended, espacially in case of
part load.
Manage sound and vibration
Compressor sound
radiation
Mechanical vibrations
Typical sounds and vibrations in systems can be
broken down into the following three categories:
• Sound radiation (through air)
• Mechanical vibrations (through parts and
structure)
For sound radiating from the compressors,
the emission path is air and the sound waves
are travelling directly from the machine in all
directions.
Sound power
dB(A)
PSH0197577
PSH02376.578.5
PSH02677.579
PSH03077. 579
PSH0347981
PSH0397880
Sound Power and attenuation are given at -7/50°C condition.
Sound power dB(A)
50Hz60Hz
A compressor generates come from vibrations
that propagate into the surrounding parts and
structure. The vibration level of a PSH019 to 039
compressor alone does not exceed 120μm peak
to peak. However, when system structure natural
frequencies are close to running frequency,
vibrations are amplified due to resonance
phenomenon.
• Gas pulsation (through refrigerant)
The following sections focus on the causes and
methods of mitigation for each of the above
sources.
Sound levels are as follows:
• For compressors running alone:
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
requirements (mounting feet, rails etc..). For
further information on mounting requirements,
please refer to section “Design compressor
mounting”.
2. Ensure that there is no direct contact (without
insulation) between vibrating components and
structure.
Gas pulsation
A high vibration level is damageable for piping
reliability and generates high sound levels.
Mitigations methods:
1. To ensure minimum vibrations transmission to
the structure, strictly follow Danfoss mounting
PSH019 to 039 have been designed and tested
to ensure that gas pulsation is optimized for the
most commonly encountered air conditioning
pressure ratio. Manifolded compressors are
equivalents to lagged sources of gas pulsation.
Therefore, pulse level can vary during time.
3. To avoid resonance phenomenon, pipings and
frame must have natural frequencies as far as
possible from running frequencies (50 or 60Hz).
Solutions to change natural frequencies are to
work on structure stiffness and mass (brackets,
metal sheet thickness or shape…)
Mitigations methods:
If an unacceptable level is identified, a discharge
muffler with the appropriate resonant volume
and mass can be installed.
21AB232986440751en-001301
Condensing temperature (°C)
Condensing temperature (°F)
Evaporating temperature (°C)
Evaporating temperature (°F)
Manage operating envelope
Requirement
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
R
The operating envelope for PSH019 to
039 scroll compressor is given in the figure
below and guarantees reliable operations of
the compressor for steady-state operation.
The discharge temperature is controlled by
OCS and limited at 131°C (268°F) (at PT1000
-31-22-414325068-13523415977
70
60
50
40
30
20
measurement location). Steady-state operation
envelope is valid for a suction superheat within
5K (9°F) to 30K (54°F) range at nominal voltage.
And a subcooling below 4K (7.2°F) is not
recommended to ensure proper liquid injection.
S.H. = 5K (9°F)
158
140
122
104
86
68
10
-35-30- 20-1001020-25-15-551525
Working range high side
Working range low side
Maximum high pressure safety switch setting
Minimum low pressure safety switch setting
Minimum low pressure pump-down switch setting
Pressure settingsR410A
bar(g)13.6-44.4
psig197-64 4
bar(g)1.7-15.7
psig25 -228
bar(g)4 6.1
psig669
bar(g)1.5
psig22
1.5 bar below nominal evap. pressure with
bar(g)
minimum of 1.7 bar(g)
22 psi below nominal evap. pressure with
psig
minimum of 25psig
50
22AB232986440751en-001301
Manage operating envelope
High and low pressure
protection
R
Low-pressure (LP) and high-pressure (HP)
safety switches must never be bypassed nor
delayed and must stop all the compressors.
LP switch auto restart must be limited to 5 times
within 12 hours.
HP safety switch must be reset manually.
Depending on application operating envelope,
you must define HP and LP limits within
operating envelope and pressure setting table
above.
Discharge gas
temperature (DGT)
protection
PSH compressor is equipped with DGT sensor
PT1000 linked to OCS board. DGT is permanently
monitored by OCS board. OCS has a relay
function so called M1-M2 connected to unit
safety chain.
If the DGT is higher than tripping set point
(default is 131°C (268°F)) for more than 1 second,
DGT protection is activated, relay output M1M2 is open. This DGT protection function is
automatically reset when the DGT is lower than
reset set point (default is 106°C (223°F)) for more
than 5 minutes.
LED2 status displayBlinking sequenceStatus
••••••••••••
••••••••••••
••••••••••••
Continuous onNo alarm
Yellow 1 time/Red 1 time
Yellow 1 time/Red 2 times
If DGT protection occurs more than 5 times
within a 1 hour window, relay M1-M2 open and
OCS requires manual reset. Manual reset is done
by power off, power on the OCS board
If DGT measurement is out of range (-50°C
(-58°F) to 180°C (356°F)), or if a fault is detected
on sensor, relay M1-M2 open and OCS requires
manual reset.
ALARM: DGT too high, automatic reset delay on-going
System evaluationHP and LP must be monitored to respect
operating envelope limitations. We consider two
types of operating envelope management:
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
Test, criteria and solutions
Tes t N °PurposeTest conditionPass criteriaSolutions
1
2
compressor
operate within
Ensure
envelope
Basic:
• HP and LP switch
• MOP (Max Operating Pressure) ensured by expansion
device
• Condensing pressure control
See “Test, criteria and solutions”
DGT
LP switch setting
Condensing pressure control
Start test at minimum foreseeable
evaporating temperature (minimum
ambient temerature...)
Continuous running within envelope
Perform a defrost test if reversible
unit
Advanced:
• HP and LP sensor
• Operating envelope limits integrated into control
logic
HP switch setting
MOP < Max evap T°
tests N
o
1 and 2
Work on compressor staging, fan
staging, water flow etc.
24AB232986440751en-001301
Manage superheat
During normal operation, refrigerant enters
the compressor as a superheated vapor. Liquid
flood back occurs when a part of the refrigerant
Liquid flood back can cause oil dilution and, in
extreme situations lead to liquid slugging that
can damage the compressor.
entering the compressor is still in liquid state.
Requirement
In steady state conditions the expansion device
must ensure a suction superheat within 5K to 30K
(9 to 54°F).
System evaluation
Use the table in relation with the application to
quickly evaluate the potential tests to perform.
ApplicationTests to perform
Non reversibleLiquid flood back test
Reversible
Liquid flood back test
Test, criteria and solutions
Tes t N °PurposeTest conditionPass criteriaSolutions
A
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
Defrost test
Steady-state
Liquid flood
back test
Transient
Check liquid
Defrost test
*Suction accumulator offers protection by trapping the liquid refrigerant upstream from the compressor. The accumulator should be sized at least 50 % of the total system
charge. Suction accumulator dimensions can impact oil return (gas velocity, oil return hole size…), therefore oil return has to be checked according to section “Manage oil in the
circuit”.
floodback
during defrost
cycle
Liquid flood back testing must be
carried out under expansion valve
threshold operating conditions:
• Lowest foreseeable evaporation,
and highest foreseeable
condensation.
• Minimum number of compressor
running.
For reversible system, perform test
in both heating and cooling mode.
Tests must be carried out with most
unfavorable conditions :
• fan staging,
• compressor staging
• …
Defrost test must be carried out in
the most unfavorable conditions
(at 0°C (32°F) evaporating
temperature).
Suction superheat >5K (9°F)
Oil superheat shall not be more than
30 sec below the safe limit defined in
the Dilution Chart. (see graph below)
Oil superheat shall not be more than
30 sec below the safe limit defined in
the Dilution Chart. (see graph below)
1. Check expansion valve selection
and setting.
• For Thermostatic expansion valve
(TXV) check bulb position...
• For Electronic expansion valve
(EXV) check measurement chain and
PID....
2. Add a suction accumulator*.
1. Check defrost logic.
In reversible systems, the defrost
logic can be worked out to limit
liquid floodback effect. (for more
details see “Control Logic”).
2. Add a suction accumulator*.
25AB232986440751en-001301
Manage superheat
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
Oil temperature sensor must be placed between
the oil sight glass and the compressor baseplate.
Some thermal paste shall be used to improve the
conductivity. The sensor must also be correctly
thermally insulated from the ambiance.
The Oil superheat is defined as:
(Oil temperature - Evaporating temperature)
PSH019 to
PSH039
Dilution Chart (reference at 20°C / 68°F ambient temperature)
-13-22-45142332415059687786
30
27.5
25
22.5
20
17.5
15
12.5
Oil Superheat (K)
10
7.5
5
2.5
0
-25-30-20-15-10-5051015202530
Evaporating Temperature °F
Safe Area
Unsafe Area
54
49.5
45
40.5
36
31.5
27
22.5
Oil Superheat (°F)
18
13.5
9
4.5
0
Evaporating Temperature °C
26AB232986440751en-001301
Manage off cycle migration
Requirement
System evaluation
R
Off -cycle refrigerant migration happens:
• when the compressor is located at the coldest
part of the installation, refrigerant vapor
condenses in the compressor.
• or directly in liquid-phase by gravity or pressure
the refrigerant diluted in the oil, or stored
in evaporator, generates poor lubrication
conditions, and may reduce bearings life time. In
extreme situations, this leads to liquid slugging
that can damage the compressor scroll set.
difference. When the compressor restarts,
• Compressor can tolerate occasional flooded
start, but it should remain exceptional situation
and unit design must prevent that this situation
happen at each start.
• Right after start, liquid refrigerant must not flow
massively to compressor.
• The charge limit is a threshold beyond some
protective measures must be taken to limit risk
of liquid slugging and extreme dilution at start.
Use the table below in relation with the system
charge and the application to quickly define
necessary safeties to implement.
ApplicationBELOW charge limitABOVE charge limit
Ensure tightness between condenser & evaporator when system is OFF
• Electronic expansion valve (EXV) must close when system stop including in power shut
down situation
External Non-return Mandatory for unit
with water condenser (W/W or reversible
A/C Chiller)
Since each installation is unique, refrigerant charge may vary
• Surface Sump Heater *
• Liquid Line Solenoid Valve**+ pump-down cycle
• External Non-Return Valve
• Surface Sump Heater *
• External Non-Return Valve
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
*Surface Sump heater
The surface sump heaters are designed to protect
the compressor against off-cycle migration of
refrigerant.
For PSH019 to 039, the surface sump heater is
located on the compressor shell.
The heater must be turned on whenever all the
compressors are off.
Surface sump heater accessories are available
from Danfoss (see section “Accessories”).
**Liquid line solenoid valve (LLSV)
A LLSV is used to isolate the liquid charge
on the condenser side, thereby preventing
against charge transfer to the compressor
Charged limits are defined in the table below:
Model
PSH0195.913
PSH023-026-030-034-0397.917
Refrigerant charge limit
in the compressor
kglbs
PSH019 to 039
during off -cycles. The quantity of refrigerant
on the low-pressure side of the system can be
further reduced by using a pump-down cycle in
association with the LLSV.
27AB232986440751en-001301
Provide power supply and electrical protection
CONTROL CIRCUIT
85 52 019 - A
Wiring information
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
Requirements:
PSH019 to 039 models are delivered with an
integrated phase protection and discharge
temperature protection on the liquid injection
control board in electrical box.
• HP safety switch and control board output (M1M2 relay) must be wired in the safety chain. Other
safety devices such as LP switch can be either
• Provide separate electrical supply for the sump
heater so that they remain energized even when
the machine is out of service (e.g. seasonal
shutdown).
• Provide separate electrical supply to liquid
injection control board. Normally the control
board should be energized together with the
unit controller.
hardware or software managed.
The wiring diagrams below are examples for a safe and reliable compressor wiring:
Control circuit ............................................................................................CC
Operating Control System ..................................................................OCS
KS
28AB232986440751en-001301
Provide power supply and electrical protection
R
Soft startsSoft starters are designed to reduce the
starting current of 3-phase AC motors.
Soft starter must be set so compressor start-up
time is always less than 0.5 seconds to ensure
proper lubrication of compressor parts.
Selection table:
Compressor model
PSH019MCI15CMCI15c
PSH023 to 030MCI25CMCI25C*
PSH034 to 039MCI50CMMCI50CM
* by-pass contactor K1 is required
• MCI15C, MCI25C, MCI50CM replaces the
contactor KM . All settings such as initial torque,
ramp-up time (less than 0.5 sec) and rampdown time are preset and do not require any
modification.
See wiring diagram:
Soft start reference
Ambient max. 40°C
Ramp-down must be set to minimum to ensure
proper discharge valve closing.
Danfoss MCI soft-start controller are available as
accessories: MCI can reduce the inrush current up
to 40%.
Soft start reference
Ambient max. 55°C
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
• MCI25C* requires a by-pass contactor K1. This
configuration is needed to withstand current
or temperature levels. All settings such as initial
torque, ramp-up time (less than 0.5 sec) and
ramp-down time are preset and do not require
any modification.
See wiring diagram:
29AB232986440751en-001301
Control logic
Safety control logic
requirements
Safeties
HP safety switch
LP safety switch
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
Integrated protection (phase
sequence/loss, DGT)
Cycle rate limit
requirements
Oil management logic
recommendations
Tripping conditionsRe-start conditions
ValueTimeValueTime
See Pressure settings table
from section “Manage
operating envelope”
Contact M1-M2 opened
Immediate, no delay.
No by-pass
Danfoss requires a minimum compressor running
time of 3 minutes to ensure proper oil return and
sufficient motor cooling.
In some cases, oil management can be enhanced
by control logic:
• If oil return test failed, a function can be
integrated in control logic to run all compressors
simultaneously during 2 minutes every hour in
order to boost oil return. Time and delay can
be fine-tuned by oil return test N°1 in section
“Manage oil in the circuit”. During oil boost, pay
special attention to superheat management to
avoid liquid flood back.
Manual reset
Maximum 5 auto reset during
Conditions back to normal.
Switch closed again
a period of 12 hours, then
manual reset.
Maximum 5 auto reset during
a period of 12 hours, then
manual reset.
Additionally, compressor must not exceed 12
starts per hour.
• In manifold system, after running long time in
full load, oil unbalance may appears. A function
can be implemented in control logic to stop all
manifold compressors during one minute every
two hours in order to balance oil. Time and delay
can be fine-tuned by Oil balancing test N°2 in
section “Manage oil in the circuit”.
Defrost logic
recommendations /
Reversible systems
Compressor 1
Compressor 2
4WV
EXV
ON
ON
Heating
100%
In reversible systems, the defrost logic can be
worked out to limit liquid flood back effect by:
1. Running full load during defrost to share liquid
refrigerant between all compressors.
The following defrost logic combines both
advantages:
2. Reducing refrigerant flooding to compressor
by transferring liquid refrigerant from one
exchanger to the other before reversing valve
thanks pressures.
Defrost
Defrost start. Stop all compressors
* EXV Opening degree and time have to be set to keep a minimum pressure for 4 way valve moving.
In any case, defrost logics must respect requirements and tests described in sections “Manage superheat” and “Manage operating envelope”.
In reversible systems, to ensure compressor reliability, the 4-way valve must not reverse when the compressor is stopped due to heating or
R
cooling demand (stop on thermostat).
30AB232986440751en-001301
4 Way Valve (4WV) stays in heating
mode.
EXV opened to transfer liquid from
outdoor to indoor exchanger thanks
to pressure difference
When pressures are almost balanced*,
Start Cp1 and Cp 2 with 0.5 seconds
change 4WV to cooling mode.
delay between 2 successive starts
4 WV stays in cooling mode.
Defrost end. Stop all compressors
EXV opened to transfer liquid from
indoor to outdoor exchanger thanks
to pressure difference
When pressures are almost balanced*,
Start Cp1 and Cp 2 with 0.5 seconds
change 4WV to heating mode.
delay between 2 successive starts
Control logic
Pump-down logic
recommendations
Pump down is initiated prior to shutting
down the last compressor on the circuit by
de-energizing a liquid line solenoid valve
or closing electronic expansion valve. When
suction pressure reached the cut-out pressure,
compressor is stopped, and liquid solenoid valve
or electronic expansion valve remains closed.
Two types of pump-down exist:
For PSH019 to 039 compressors, an external
Non-Return Valve (NRV) in the discharge line is
recommended.
• One shot pump down (preferred): when
last compressor of the circuit stops, suction
presssure is decreased 1.5 bar (22 psi) below
nominal evaporating pressure with minimum
of 1.7 bar(g) (25 psig). Even if suction pressure
increases again, the compressor will not restart.
• Continuous pump-down: traditional pumpdown, Compressor restarts automatically
when suction pressure increases up to 4 cycles
maximum.
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
31AB232986440751en-001301
Reduce moisture in the system
Requirements
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
Solutions
R
Excessive air and moisture
• can increase condensing pressure and cause
high discharge temperatures.
• can create acid giving rise to copper platting.
• can destroy the lubricating properties of the oil.
PSH019 to 039 compressors are delivered with
< 100ppm moisture level.
At the time of commissioning, system moisture
content may be up to 100ppm.
To achieve this requirement, a properly sized
and type of drier is required. Important selection
criteria’s include:
• driers water content capacity,
• system refrigeration capacity,
• system refrigerant charge.
All these phenomena can reduce service life
and cause mechanical and electrical compressor
failure.
During operation, the filter drier must reduce this
to a level between 20 and 50ppm.
For new installations with PSH019 to 039
compressors with polyolester oil, Danfoss
recommends using the Danfoss DML (100%
molecular sieve) solid core filter drier.
32AB232986440751en-001301
Assembly line procedure
R
Compressor storage
Compressor holding
charge
Handling
Store the compressor not exposed to rain,
corrosive or flammable atmosphere between
-35°C (-31°F) and 70°C (158°F) when charged
Each compressor is shipped with a nominal dry
nitrogen holding charge between 0.3bar (4psi)
and 0.7bar (10psi) and is sealed with elastomer
plugs.
Respect the following sequence to avoid
discharge check valve gets stuck in open
position:
Each Danfoss PSH019 to 039 scroll
compressor is equipped with two lift rings on the
top shell.
• Always use both these rings when lifting the
compressor.
• Use lifting equipment rated and certified for
the weight of the compressor or compressor
assembly.
• A spreader bar rated for the weight of the
compressor is highly recommended to ensure a
better load distribution.
with nitrogen and between -35°C (-31°F) and
Ts max value (see section "Pressure equipment
directive") when charged with R410A refrigerant.
• Remove the suction plug first
• Remove the discharge plug afterwards
An opened compressor must not be
exposed to air for more than 20 minutes to avoid
moisture is captured by the POE oil.
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATIONSYSTEM DESIGN
• The use of lifting hooks closed with a clasp is
recommended.
• For tandem and trio assemblies, use a spreader
bar and all compressor rings as shown in picture
below.
• Never use the lift rings on the compressor to lift
the full unit.
Maintain the compressor in an upright position
during all handling manoeuvres (maximum of
15° from vertical).
HEAVY
do not lift
manually
Spreader bar
Spreader bars
Slings
Frame
33AB232986440751en-001301
Assembly line procedure
Piping assemblyGood practices for piping assembly is a pre-requisite to ensure compressor life time (system
cleanliness, brazing procedure etc.)
System cleanliness
Circuit contamination possible cause:Requirement:
Brazing and welding oxidesDuring brazing, flow nitrogen through the system.
Particles and burrs
GENERAL INFORMATIONPRODUCT INFORMATIONSYSTEM DESIGNORDERING INFORMATIONINTEGRATION INTO SYSTEM
Moisture and air
Remove any particles and burrs generated by tube
cutting and hole drilling.
Use only clean and dehydrated refrigeration grade
copper tubing.
Opened compressor must not be exposed to air more
than 20 minutes to avoid moisture captured by oil.
Brazing procedure:
• Brazing operations must be performed by
qualified personnel.
• Make sure that no electrical wiring is connected
to the compressor.
• To prevent compressor shell and electrical box
overheating, use a heat shield and/or a heatabsorbent compound.
• Clean up connections with degreasing agent
• Flow nitrogen through the compressor.
• Use flux in paste or flux coated brazing rod.
• Use brazing rod with a minimum of 5% silver
content.
Before eventual un-brazing of the
compressor or any system component, the
refrigerant charge must be removed.
System pressure test and
leak detectionThe compressor has been strength tested
and leak proof tested (<3g/year) at the factory.
For system tests:
• Always use an inert gas such as Nitrogen or
Helium.
• It is recommended to use double-tipped torch
using acetylene to ensure a uniform heating of
connection.
• For discharge connections brazing time should
be less than 2 minutes to avoid NRVI damages
if any.
• To enhance the resistance to rust, a varnish on
the connection is recommended.
heat shield
C
A
B
• Pressurize the system on HP side first then LP
side.
• Do not exceed the following pressures indicated
in table below
34AB232986440751en-001301
Maximum compressor test pressuresPSH019-023-026-030-034-039
Maximum compressor test pressure high side (HP)
Maximum compressor test pressure low side (LP)
48.7 bar (g) (706 psig)
HP-LP<37bar (537 psi)
33.3 bar (g) (483 psig)
HP-LP<5bar (73 psi)
Maximum speed 4.8 bar/s (70 psi/s)
Assembly line procedure
Vacuum evacuation and
moisture removal
Refrigerant charging
Dielectric strength and
insulation resistance tests
R
Requirements:
• Never use the compressor to evacuate the
system.
• Connect a vacuum pump to both the LP and HP
sides.
• Evacuate the system to a pressure of 500μm Hg
(0.67mbar/0.02 in.Hg) absolute.
R
Initial charge:
• For the initial charge, the compressor must not
run.
• Charge refrigerant as close as possible to the
nominal system charge.
• This initial charging operation must be done in
liquid phase between the condenser outlet and
the filter drier.
Several tests have been performed on each
compressor at the factory between each phase
and ground.
• Dielectric strength test is done with a high
potential voltage (hi-pot) of 2Un +1000V AC
at least, and leakage current must be less than
5mA.
• Insulation resistance is measured with a 500V
DC megohm tester and must be higher than
1megohm.
Recommendations:
• Energized heaters improve moisture removal.
• Alternate vacuum phases and break vacuum
with Nitrogen to improve moisture removal.
For more detailed information see “Vacuum
pump-down and dehydration procedure”
TI-026-0302.
GENERAL INFORMATIONPRODUCT INFORMATIONSYSTEM DESIGNORDERING INFORMATIONINTEGRATION INTO SYSTEM
If needed, a complement of charge can be
done before evaporator, in liquid phase while
compressor is running by slowly throttling liquid
in.
Never bypass safety low pressure switch.
For more detailed information see
“Recommended refrigerant system charging
practice“ FRCC.EN.050.
Recommendations:
• Additional dielectric test is not recommended
as it may reduce motor lifetime. Nevertheless, if
such as test is necessary, it must be performed
at a lower voltage.
• Insulation resistance test can be done.
• The presence of refrigerant around the
motor windings will result in lower resistance
values to ground and higher leakage current
readings. Such readings do not indicate a faulty
compressor. To prevent this, the system can be
first operated briefly to distribute refrigerant.
Do not use a megohm meter nor apply
R
power to the compressor while it is under
vacuum as this may cause internal damage.
35AB232986440751en-001301
Commissioning
Preliminary check
Check electrical power supply:
• Phase order: Reverse rotation is obvious if the
compressor don’t build up pressure and sound
level is abnormal high. For PSH019 to 039
compressor have phase protection function
on OCS. Reverse rotation will be automatically
detected and trip the compressor by opening
the M1-M2 relay output. For more details refer
to section “Motor protection”.
• Voltage and voltage unbalance within tolerance:
For more details refer to section “Motor voltage”.
Initial start-up
GENERAL INFORMATIONPRODUCT INFORMATIONSYSTEM DESIGNORDERING INFORMATIONINTEGRATION INTO SYSTEM
System monitoring
• Surface sump heaters must be energized at least
6 hours in advance to remove refrigerant.
• A quicker start-up is possible by “jogging” the
compressor to evacuate refrigerant. Start the
The system must be monitored after initial
startup for a minimum of 60 minutes to ensure
proper operating characteristics such as:
• Correct superheat and subcooling.
• Current draw of individual compressors within
acceptable values (max operating current).
• No abnormal vibrations and noise.
• Correct oil level.
compressor for 1 second, then wait for 1 to 2
minutes. After 3 or 4 jogs the compressor can
be started. This operation must be repeated for
each compressor individually.
If Oil Top-up is needed, it must be done while the
compressor is idle. Use the schrader connector
or any other accessible connector on the
compressor suction line. Always use original
Danfoss POE oil 160SZ from new cans.
For more detailed information see “Lubricants
filling in instructions for Danfoss Commercial
Compressors” TI 2-025-0402.
36AB232986440751en-001301
Dismantal and disposal
Danfoss recommends that compressors and compressor oil should be recycled by a
suitable company at its site.
GENERAL INFORMATIONPRODUCT INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATION
37AB232986440751en-001301
Ordering information and packaging
Packaging
Single pack
GENERAL INFORMATIONPRODUCT INFORMATIONSYSTEM DESIGNINTEGRATION INTO SYSTEMORDERING INFORMATION
Compressor
model
PSH01956522.2447018.5071828. 2769152
PSH02356522.2447018.5071828.2776168
PSH02656522.2447018.5071828.277616 8
PSH03056522.2447018. 5071828. 2779174
PSH03456522. 2447018. 5071828.2781179
PSH03956522.2447018 .5071828.2784185
LengthWidthHeightGross weight
mminchmminchmminchkglbs
Industrial pack
Compressor
model
PSH019
PSH023
PSH026
PSH030
PSH034
PSH039
* Nbr: number of compressor per pack
: Full package version
: Bare compressor version
Nb *
6 / 8
6 / 8
6 / 8
6 / 8
6 / 8
6 / 8
LengthWidthHeightGross weight
mminchmminchmminchkglbs
115045.2895037.4 068026.773868512
115045.2895037.4 075029.534249352
115045.2895037.4 075029.534249352
115045.2895037.4 075029.534409702
115045.2895037.4 075029.534529962
115045.2895037.4 075029.5347010362
Static
stacking
pallets
38AB232986440751en-001301
Ordering information and packaging
Ordering information
Single pack
Danfoss PSH019 to 039 scroll compressors can
be ordered in either industrial or single packs.
8154001 Danfoss Commercial Compressors blue spray paintAll modelsSingle pack1
42AB232986440751en-001301
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