Danfoss HHP Series Instruction Manual

Danfoss Heat Pump scroll
compressors, HHP-Series
50Hz - R407C
Application guidelines
http://cc.danfoss.com

Content
Scroll compression principle ........................................................................................... 6
Scroll compressor components.................................................................................................................................6
The scroll compression process.................................................................................................................................7
Performance .....................................................................................................................................................................7
Compressor model designation ...................................................................................... 8
Nomenclature ..................................................................................................................................................................8
Label....................................................................................................................................................................................8
Technical specications ................................................................................................... 9
50-Hz data .........................................................................................................................................................................9
Performance table..........................................................................................................................................................9
Dimensions ...................................................................................................................... 10
HHP015-019-021-026...................................................................................................................................................10
HHP030-038-045............................................................................................................................................................11
Electrical data, connections and wiring......................................................................... 12
Motor voltage .................................................................................................................................................................12
Wiring connections.......................................................................................................................................................12
IP rating .............................................................................................................................................................................13
LRA (Locked Rotor Amp).............................................................................................................................................13
MCC (Maximum Continuous Current)....................................................................................................................13
Max Oper. A (Maximum Operating Amp) .............................................................................................................13
Winding resistance........................................................................................................................................................13
Electrical connections ..................................................................................................................................................13
Nominal capacitor value .............................................................................................................................................14
Internal motor protection...........................................................................................................................................14
Phase sequence and reverse rotation protection..............................................................................................14
Voltage imbalance ........................................................................................................................................................14
Approvals and certications........................................................................................... 15
Approvals and certicates..........................................................................................................................................15
Pressure equipment directive 97/23/EC................................................................................................................15
Low voltage directive 73/23/EC, 93/68/EC...........................................................................................................15
Internal free volume .....................................................................................................................................................15
Operating conditions ...................................................................................................... 16
Refrigerant and lubricants..........................................................................................................................................16
Motor supply...................................................................................................................................................................16
Compressor ambient temperature..........................................................................................................................16
Application envelope...................................................................................................................................................17
R407C ................................................................................................................................................................................17
Maximum discharge gas temperature...................................................................................................................17
High and low pressure protection...........................................................................................................................18
On/o cycling (cycle rate limit).................................................................................................................................18
4FRCC.PC.017.A2.02
Application Guidelines

Content
System design recommendations.................................................................................. 19
General ..............................................................................................................................................................................19
Essential piping design considerations.................................................................................................................19
Refrigerant charge limit ..............................................................................................................................................20
Reversible heat pump systems.................................................................................................................................20
Crankcase heater............................................................................................................................................................22
Minimum sump superheat.........................................................................................................................................22
Loss of charge protection ...........................................................................................................................................22
Oil level checking and top-up...................................................................................................................................22
High pressure ratio........................................................................................................................................................22
Preventing liquid ood back .....................................................................................................................................22
Testing for excessive liquid ood back ..................................................................................................................22
Water utilising systems................................................................................................................................................22
Sound and vibration management................................................................................ 23
Running sound level.....................................................................................................................................................23
Sound generation in a refrigeration system / air conditioning system .....................................................23
Compressor sound radiation.....................................................................................................................................23
Mechanical vibrations..................................................................................................................................................23
Gas pulsation...................................................................................................................................................................23
Installation ....................................................................................................................... 24
System cleanliness.........................................................................................................................................................24
Compressor handling and storage..........................................................................................................................24
Compressor mounting.................................................................................................................................................24
Compressor holding charge ......................................................................................................................................24
Tube brazing procedure..............................................................................................................................................24
Brazing material .............................................................................................................................................................24
Vacuum evacuation and moisture removal .........................................................................................................25
Liquid line lter driers ..................................................................................................................................................26
Refrigerant charging.....................................................................................................................................................26
Insulation resistance and dielectric strength ......................................................................................................26
Compressor replacement after motor burn out.................................................................................................26
Ordering information and packaging............................................................................ 27
Packaging .........................................................................................................................................................................27
Packaging details...........................................................................................................................................................27
Ordering information and packaging....................................................................................................................27
Spare parts & accessories................................................................................................ 28
Run capacitors for PSC wiring ...................................................................................................................................28
Rotolock adaptor set ....................................................................................................................................................28
Rotolock adaptor ...........................................................................................................................................................28
Crankcase heater............................................................................................................................................................28
Discharge temperature protection .........................................................................................................................29
Lubricant...........................................................................................................................................................................29
Mounting hardware......................................................................................................................................................29
5FRCC.PC.017.A2.02
Application Guidelines

Scroll compression principle
The motor stator is rigidly attached to the shell.
The rotor is shrink-t onto the eccentric shaft. The
shaft is supported by two bearings, one in the
crankcase and the second below the motor.
Scroll compressor
components
6FRCC.PC.017.A2.02
Application Guidelines

Scroll compression principle
Danfoss Heat Pump scroll compressors are
manufactured using the most advanced
machining, assembly, and process control
techniques. In design of both the compressor
and the factory, very high standards of reliability
and process control were rst priority. The result
is a highly ecient product with the highest
reliability obtainable, and a low sound level.
The Danfoss Heat Pump scroll compressor
referenced in this guide is a fully compliant
scroll and actually improves with run time in
it's early commissioning. A seventy-two hour
run-in is recommended to meet performance
expectations.
The entire scroll compression process is illustrated
below. The centre of the orbiting scroll traces a
circular path around the centre of the xed scroll.
This movement creates compression pockets
between the two scroll elements.
Low pressure suction gas is trapped within each
crescent-shaped pocket as it forms; continuous
motion of the orbiting scroll serves to seal
the pocket, which decreases in volume as the
pocket moves towards the centre of the scroll
set, with corresponding increase in gas pressure.
Maximum compression is achieved, as the pocket
reaches the discharge port at the centre.
Scroll compression is a continuous process: when
one pocket of gas is being compressed during
the second orbit, another gas quantity enters
a new pocket formed at the periphery, and
simultaneously, another is being discharged.
The scroll compression
process
SUCTION
COMPRESSION
DISCHARGE
Performance
7FRCC.PC.017.A2.02
Application Guidelines

Compressor model designation
Label
Nomenclature
Serial number
S K 1234509
03
Production year
Production week
Manufacturing location
Incremental number
Type FeaturesMotorSize
HHP P6T4L
030
Application:
H: high temperature
Family:
HP: heat pump R407C PVE
Nominal capacity:
Model variation
T motor design
Motor voltage code
4: 380-400V/3~/50 Hz
5: 220-240V/1~/50 Hz
Motor protection
L: internal motor protection
Tubing and electrical connections
P: brazed connections, spade terminals
C: brazed connections, screw terminals
Other features
Oil sight
glass
Oil equali-
sation
Oil
drain
LP gauge
port
Gas equali-
sation port
None
6
None None None None
8FRCC.PC.017.A2.02
Application Guidelines

Technical specications
Performance table
50-Hz data
Model
Heating
capacity Power input Max. A. Heating eciency Swept volume Displacement Oil charge Net weight
W W A COP W/W (cm3/rev) m3/hr @2900
rpm Lkg
HHP015T4LP6 4800 1540 5.1 3.13 34 5.9 1.06 31
HHP015T5LP6 4880 1660 14.2 2.93 34 5.9 1.06 31
HHP019T4LP6 5780 1910 5.8 3.02 41 7.1 1.06 33
HHP019T5LP6 5830 2040 17.7 2.86 41 7.1 1.06 33
HHP021T4LP6 6410 2030 5.8 3.16 46 81.06 33
HHP021T5LP6 6630 2110 18.2 3.15 46 81.06 33
HHP026T4LP6 8100 2520 7.1 3.22 57 10 1.06 33
HHP026T5LP6 8160 2680 22.7 3.04 57 10 1.06 33
HHP030T4LC6 9700 3070 8.6 3.17 67 11.7 1.57 33
HHP030T5LC6 9790 3190 27.7 3.07 67 11.7 1.57 42
HHP038T4LC6 12050 3730 10.8 3.23 82 14.2 1.57 42
HHP038T5LC6 12140 3850 35.2 3.16 82 14.2 1.57 42
HHP045T4LC6 13940 4300 12.6 3.25 99 17.2 1.57 42
Evaporating temperature: -7° C Condensing temperature: 50°C Superheat: 10 K Subcooling: 5 K
Subject to modication without prior notication Conditions: 400V/3ph/50Hz (motor T4), 230V/1ph/50 Hz (motor T5)
For full data details and capacity tables refer to Online Datasheet Generator : www.danfoss.com/odsg
Model To -25 -20 -15 -10 -5 0 5 10 15
Tc HPe HPe HPe HPe HPe HPe HPe HPe HPe
HHP015T4
40 2 550 1.1 3 070 1.1 3 720 1.2 4 510 1.3 5 450 1.3 6 520 1.4 7 730 1.4 9 080 1.4 10 570 1.4
50 2 620 1.5 3 050 1.5 3 620 1.5 4 320 1.5 5 150 1.6 6 120 1.6 7 220 1.7 8 460 1.7 9 840 1.7
60 - - - - 3 860 2.2 4 410 2.1 5 090 2.1 5 890 2.1 6 830 2.1 7 900 2.1 9 100 2.1
HHP019T4
40 3 070 1.3 3 680 1.4 4 450 1.5 5 400 1.5 6 520 1.6 7 810 1.7 9 270 1.7 10 900 1.7 12 690 1.7
50 3 180 1.7 3 680 1.7 4 340 1.8 5 180 1.9 6 180 1.9 7 340 2.0 8 670 2.1 10 160 2.2 11 830 2.2
60 - - - - 4 660 2.3 5 300 2.4 6 110 2.4 7 070 2.5 8 200 2.6 9 480 2.7 10 930 2.8
HHP021T4
40 3 530 1.4 4 250 1.5 5 090 1.6 6 080 1.7 7 230 1.7 8 570 1.8 10 100 1.8 11 84 0 1.7 13 820 1.7
50 3 430 1.6 4 080 1.8 4 860 1.9 5 770 2.0 6 830 2.1 8 070 2.1 9 500 2.2 11 140 2.2 13 000 2.2
60 ----4 710 2.2 5 530 2.3 6 510 2.5 7 650 2.6 8 970 2.7 10 490 2.8 12 240 2.8
HHP026T4
40 4 540 1.7 5 410 1.9 6 440 2.0 7 650 2.1 9 070 2.1 10 740 2.2 12 690 2.2 14 950 2.1 17 550 2.0
50 4 590 2.0 5 350 2.1 6 260 2.3 7 330 2.4 8 610 2.6 10 120 2.6 11 90 0 2.7 13 970 2.7 16 370 2.7
60 ----6 240 2.7 7 150 2.9 8 250 3.0 9 560 3.2 11 130 3.3 12 980 3.3 15 150 3.3
HHP030T4
40 4 910 2.1 6 100 2.3 7 480 2.4 9 050 2.6 10 830 2.6 12 830 2.7 15 060 2.7 17 520 2.8 20 240 2.9
50 4 830 2.3 5 940 2.6 7 230 2.8 8 690 3.0 10 350 3.1 12 200 3.2 14 270 3.4 16 560 3.5 19 090 3.6
60 ----7 000 3.1 8 330 3.4 9 850 3.6 11 550 3.8 13 440 4.0 15 540 4.2 17 870 4.4
HHP038T4
40 6 150 2.4 7 600 2.8 9 360 3.0 11 390 3.2 13 660 3.2 16 130 3.3 18 750 3.3 21 510 3.4 24 360 3.6
50 5 730 2.2 7 120 2.8 8 800 3.3 10 740 3.6 12 890 3.8 15 220 4.0 17 700 4.1 20 280 4.2 22 940 4.4
60 - - - - 8 090 3.2 9 930 3.8 11 970 4.2 14 170 4.5 16 500 4.7 18 920 5.0 21 400 5.2
HHP045T4
40 7 110 3.0 8 800 3.1 10 830 3.3 13 180 3.5 15 800 3.7 18 660 3.8 21 700 3.9 24 890 3.8 28 180 3.7
50 6 630 3.5 8 240 3.7 10 190 3.9 12 420 4.2 14 910 4.4 17 610 4.6 20 480 4.7 23 460 4.8 26 540 4.8
60 - - - - 9 360 4.5 11 490 4.8 13 850 5.1 16 400 5.5 19 100 5.7 21 890 6.0 24 760 6.1
Legend: To: Evaporating temperature in °C H: Heating capacity in W Superheat = 5 K
Tc: Condensing temperature in °C Pe: Power input in kW Subcooling = 5 K
9FRCC.PC.017.A2.02
Application Guidelines

Dimensions
Mounting grommetTerminal box
Refer to section "Spare parts and accessories" for over-
view of shipped mounting accessories
HHP015-019-021-026
Quick connect spade terminals
P terminal box type
1.7
41
Ø 41
29.5
5/16” - 18 UNC
self tapping
Recommended torque for mounting bolts:
11 Nm (±1 Nm)
Ø11
238.8
4 x Ø 19.0 - 20.0
95.25
128.5
111.3
69.4 - 71.4 34° 31°
45°
14°
109.7
95.25
190.25 - 190.50
238.8
190.25 - 190.75
HHP 015-019-021-026
394.4
Suction line
(1) 19.13-19.23
(3/4 inch)
163.5 - 165.5
72.1 - 75.1
360.4
194.9 230.8
10.7
19
Discharge line
12.75-12.85
(1/2 inch)
P6
All dimensions in mm
10 FRCC.PC.017.A2.02
Application Guidelines

Dimensions
Mounting grommetTerminal boxes
Refer to section "Spare parts and accessories" for over-
view of shipped mounting accessories
HHP030-038-045
1.7
41
Ø 41
29.5
5/16” - 18 UNC
self tapping
Recommended torque for mounting bolts:
11 Nm (±1 Nm)
Ø11
Ring connect screw terminals
C terminal box type
C
T₁
S
T₂
R
T₃
239
190.25 - 190.75
95.25
133.6
121
78.5 - 80.5
182.54 - 184.54
Suction line
22.30-22.48
(7/8 inch)
Discharge line
12.75-12.85
(1/2 inch)
92.0 - 94.0
402.7
202.4
261
19
10.9
435.9
34° 31° 45°
14°
4 x Ø 19.0 - 20.0
239
190.25 - 190.75
119.2
95.25
HHP030-038-045
All dimensions in mm
C6
11FRCC.PC.017.A2.02
Application Guidelines

Electrical data, connections and wiring
Danfoss Heat Pump scroll compressors are available in 2 dierent motor voltages.Motor voltage
Danfoss Heat Pump scroll compressors will only
compress gas while rotating counter-clockwise
(when viewed from the compressor top). Since
single-phase motors will start and run in only
one direction, reverse rotation is not a major
consideration. Three-phase motors, however,
will start and run in either direction, depending
on the phase angles of the supplied power. Care
must be taken during installation to ensure that
the compressor operates in the correct direction
(see “Phase sequence and reverse rotation
protection”).
The drawings below show electrical terminal
labelling and should be used as a reference
when wiring the compressor. For three phase
applications, the terminals are labelled T1, T2, and
T3. For single-phase applications the terminals
are labelled C (common), S (start), and R (run).
Prior to energizing, verify that leads and terminal
connectors are in proper working condition.
Warning: For safety reasons, make voltage
measurements at the unit contactor, not at
compressor terminals. Always keep the terminal
cover in place when the compressor is energized.
The terminal cover and gasket should be installed
prior to operation of the compressor. The terminal
cover has two outside tabs, 180 degrees apart,
that engage the terminal fence. When installing
the cover, check that it is not pinching the lead
wires. Both the inside of the terminal cover and
the gasket have labels for the terminal pins: C
(common), R (run), and S (start).
Wiring connections
Terminal cover mounting
Terminal cover removal
Quick connect spade terminals
P terminal box type
push
push
push
Motor voltage code 4 Motor voltage code 5
Nominal voltage 50 Hz 380-400V-3-50 Hz 220-240V-1-50 Hz
Voltage range 50 Hz 340 - 440 198 - 264
Ring connect screw terminals
C terminal box type
C
T₁
S
T₂
R
T₃
12 FRCC.PC.017.A2.02
Application Guidelines

Electrical data, connections and wiring
The compressor terminal box IP rating according to CEI 529 is IP22 for all models. IP ratings is only valid
when correctly sized cable glands of the IP rating is applied.
• First numeral, level of protection against contact and foreign objects
2protection against object size over 12.5 mm (ngers of similar)
• Second numeral, level of protection against water
2protection against dripping water when tilted up to 15°
IP rating
LRA is the higher average current as measured on
a mechanically blocked compressor tested under
nominal voltage. LRA is printed on the nameplate.
The LRA value can be used as a rough estimation
for the starting current. However in most cases,
the real starting current will be lower. Many
countries have dened limits for the starting
current in domestic use. A soft starter can be
applied to reduce starting current.
The MCC is the current at which the internal
motor protection trips under maximum load and
low voltage conditions.
This MCC value is the maximum at which
the compressor can be operated in transient
conditions and out of the application envelope.
Above this value the overload will switch o to
protect the motor.
MCC (Maximum
Continuous Current)
LRA (Locked Rotor Amp)
Winding resistance Winding resistance is the resistance between
indicated terminal pins at 25°C (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
dierent value than 25°C, the measured resistance
must be corrected with following formula:
a + tamb
Rtamb = R25°C
a + t25°C
t25°C: reference temperature = 25°C
tamb: temperature during measurement (°C)
R25°C: winding resistance at 25°C
Ramb: winding resistance at tamb
coecient a= 234.5
The Danfoss Heat Pump scroll compressors are
designed to operate without any assistance if
running within the dened nominal voltage. PSC
wiring is sucient (see below).
Electrical connections
The start winding (C-S) of the motor remains in
circuit through a permanent (run) capacitor.
This permanent (run) capacitor is connected
between the start winding (C-S) and the run
winding (C-R).
PSC wiring
The Max Oper. A is the current when the
compressor operates at maximum load conditions
and 10% below nominal voltage.
This value which is the max rated load current for
the compressor is new on the nameplate.
Max Oper. A can be used to select cables and
contactors.
In normal operation, the compressor current
consumption is always less than the Max Oper. A
value.
Max Oper. A (Maximum
Operating Amp)
C
S
R
Line Run
Capacitor
13FRCC.PC.017.A2.02
Application Guidelines

Electrical data, connections and wiring
Nominal capacitor value
The Danfoss Heat Pump scroll compressors will
only operate properly in a single direction. Use
a phase meter to establish the phase orders and
connect line phases L1, L2 and L3 to terminals
T1, T2 and T3, respectively. For three-phase
compressors, the motor will run equally well
in both directions. Reverse rotation results in
excessive noise; no pressure dierential between
suction and discharge; and suction line warming
rather than immediate cooling. A service
technician should be present at initial start-up to
verify that supply power is properly phased and
that compressor and auxiliaries are rotating in the
correct direction.
Danfoss Heat Pump scroll compressors are
designed to operate for a maximum of 150 hours
in reverse, but as a reverse rotation situation can
go unnoticed for longer periods, phase monitors
are recommended.
At brief power interruptions, reverse rotation can
occur with single phase compressors. In this case
the internal protector will stop the compressor.
It will have to cool down and will restart safely
afterwards.
For three-phase applications the voltage
measured at the compressor terminals for each
phase should be within ± 2% of the average for
all phases.
Phase sequence and
reverse rotation
protection
Voltage imbalance
Internal motor protection The Danfoss Heat Pump scroll compressors are
equipped with an internal line break protector
mounted on the motor windings. The protector
is an automatic reset device, containing a snap
action bimetal switch.
Internal protectors respond to over-current and
overheating. They are designed to interrupt
motor current under a variety of fault conditions,
such as failure to start, running overload, and fan
failure.
If the internal overload protector trips out, it must
cool down to about 60°C to reset. Depending on
ambient temperature, this may take up to several
hours.
In single-phase compressors, internal protectors
guard against external miswiring, such as
reversing electrical connections to the Run (R) and
Start (S) terminals. In three-phase compressors
the internal protectors provide protection during
secondary single-phase conditions (loss of phase).
If start assist is required, in case of operating
below the nominal voltage, a CSR starting device
is required.
During start-up, the start winding (C-S) is
energised through an electromagnetic potential
relay and a start capacitor.
A permanent (run) capacitor is wired between the
start winding (C-S) and the run winding (C-R).
CSR wiring
PSC wiring
Run capacitor
HHP015T5LP6 40
HHP019T5LP6 60
HHP021T5LP6 60
HHP026T5LP6 70
HHP030T5LC6 50
HHP038T5LC6 55
Start
Capacitor
Potential
Relay
1
2
5
C
S
R
Line Run
Capacitor
14 FRCC.PC.017.A2.02
Application Guidelines

Approvals and certications
The Danfoss Heat Pump scroll compressors
comply with the following approvals and
certicates.
Certicates are listed on the product datasheets:
http://www.danfoss.com/odsg
Approvals and certicates
Pressure equipment
directive 97/23/EC
Low voltage directive
73/23/EC, 93/68/EC
Internal free volume
CE 0062 or CE 0038
(European Directive) All models
UL
(Underwriters Laboratories) All models
Other approvals / certicates CB certicate available upon request
Products
Manufacturer's declaration of incorporation
ref. EC Machines Directives 98/392/CE Contact Danfoss
Products Internal free volume at LP side without oil (litre)
HHP015-019-021-026 2.93
HHP030-038-045 3.44
Products HHP015-019-021-026-030-038
Refrigerating uids Group 2
Category PED I
Evaluation module no scope
15FRCC.PC.017.A2.02
Application Guidelines

Operating conditions
The Danfoss Heat Pump scroll compressors
application range is inuenced by several
parameters which need to be monitored for a
safe and reliable operation.
Theseparametersandthemainrecommendations
for good practice and safety devices are explained
hereunder.
• Refrigerant and lubricants
• Motor supply
• Compressor ambient temperature
• Application envelope (evaporating
temperature, condensing temperature, return
gas temperature)
General information
Refrigerant and lubricants
When choosing a refrigerant, dierent aspects
must be taken into consideration:
• Legislation (now and in the future)
• Safety
• Application envelope in relation to expected
running conditions
• Compressor capacity and eciency
• Compressor manufacturer recommendations &
guidelines
Additional points could inuence the nal choice:
• Environmental considerations
• Standardisation of refrigerants and lubricants
• Refrigerant cost
• Refrigerant availability
Oil type - PVE Polyvinyl ether (PVE) is an innovative refrigeration
lubricant for HFC refrigerant systems. PVE is as
hygroscopic as existing polyolester lubricants
(POE), but PVE doesn’t chemically react with
water; no acids are formed and compressor
evacuation is easier.
The compressor technology applied in the
Danfoss Heat Pump scroll compressors in
combination with PVE lubricant provides the
best possible result in terms of reliability and
compressor lifetime.
The PVE lubricant is compatible with R22 which
makes the Danfoss Heat Pump scroll compressors
a very versatile multi- refrigerant solution.
Motor supply The Danfoss Heat Pump scroll compressors can
be operated at nominal voltages as indicated in
section "Electrical data, connections and wiring".
Under-voltage and over-voltage operation is
allowed within the indicated voltage ranges. In
case of risk of under-voltage operation, special
attention must be paid to current draw and
start assist for single-phase compressors may be
required.
The Danfoss Heat Pump scroll compressors
can be applied from -35°C to 50°C ambient
temperature. The compressors are designed
as 100  % suction gas cooled without need for
additional fan cooling. Ambient temperature has
very little eect on the compressor performance.
In case of enclosed tting and high ambient
temperature it’s recommend to check the
temperature of power wires and conformity to
their insulation specication.
In case of safe tripping by the internal compressor
overload protection the compressor must cool
down to about 60°C before the overload will
reset. A high ambient temperature can strongly
delay this cool-down process.
Although the compressor itself can withstand low
ambient temperature, the system may require
specic design features to ensure safe and reliable
operation. See section ‘Specic application
recommendations’.
Compressor ambient
temperature
High ambient temperature
Low ambient temperature
16 FRCC.PC.017.A2.02
Application Guidelines

Operating conditions
Application envelope
The discharge temperature depends mainly on
the combination of evaporating temperature,
condensing temperature and suction gas
superheat. Discharge gas temperature should
be controlled with an isolated thermocouple or
thermostat attached to the discharge line 15 cm
from the compressor shell. Maximum discharge
gas temperature must not exceed 140°C when
the compressor is running within the approved
operating envelope.
Maximum discharge gas
temperature
Discharge gas temperature
protection (DGT)
DGT protection is required if the high and low
pressure switch settings do not protect the
compressor against operations beyond its
specic application envelope. Please refer to
the examples below, which illustrate where DGT
protection is required (n°1) and where it is not
(n°2).
The compressor must not be allowed to cycle
on the discharge gas thermostat. Continuous
operations beyond the compressor’s operating
range will cause serious damage to the
compressor!
A DGT accessory is available from Danfoss: refer to
section "Spare parts and accessories".
The operating envelope for Danfoss Heat
Pump scroll compressors are given in the gure
below, where the condensing and evaporating
temperatures represent the range for steady-state
operation. Under transient conditions, such as
start-up and defrost for heat pump applications,
the compressor may operate outside this
envelope for short periods.
The operating limits serve to dene the
envelope within which reliable operations of the
compressor are guaranteed:
• Maximum discharge gas ow temperature:
140°C,
• A suction superheat below 5 K is not
recommended due to the risk of liquid ood
back,
• Maximum superheat of 30 K as long as maximum
discharge gas temperature is not exceeded,
• Minimum and maximum evaporating and
condensing temperatures as per the operating
envelopes.
R407C
10
20
30
40
50
60
70
-25 -20 -15 -10 -5 0 5 10 15 20
Continuous operation ranges - R407C dew
Evaporating temperature (°C)
Condensing temperature (°C)
SH = 5 K
SH = 10 K
17FRCC.PC.017.A2.02
Application Guidelines

Operating conditions
Example 1 (R407C)
LP switch setting: LP1= 1.1 bar (g) (-20°C)
HP switch setting: HP1= 24.3 bar (g) (60°C)
The LP and HP switches don't protect
suciently from operation outside the
envelope. A DGT protection is required
to avoid operation in the hatched area.
Example 2 (R407C)
LP switch setting: LP2 = 2.3 bar (g) (-9°C)
HP switch setting: HP2 = 18.8 bar (g) (50°C)
The LP and HP switches protect from
operation outside the envelope. No
DGT protection required.
A high-pressure (HP) safety switch is
recommended to shut down the compressor
should the discharge pressure exceed the values
shown in the table below. The high-pressure
switch can be set to lower values depending on
the application and ambient conditions. The HP
switch must either be placed in a lockout circuit or
consist of a manual reset device to prevent cycling
around the high-pressure limit. If a discharge
valve is used, the HP switch must be connected
to the service valve gauge port, which must not
be isolated.
Note: because power consumption of scroll
compressors is almost directly proportional to
discharge pressure, the high-pressure control can
be used to indirectly limit the maximum current
draw. A high-pressure control used in this manner
however can never replace an external overload
protector.
High pressure
High and low pressure
protection
A low pressure (LP) safety switch is recommended.
Deep vacuum operations of a scroll compressor
can cause internal electrical arcing and scroll
instability. Danfoss Heat Pump scroll compressors
exhibit high volumetric eciency and may draw
very low vacuum levels, which could induce such
a problem. The minimum low-pressure safety
switch (loss of charge safety switch) setting is
given in the above table. For systems without
pump-down, the LP safety switch must either be
a manual lockout device or an automatic switch
wired into an electrical lockout circuit. The LP
switch tolerance must not allow for vacuum
operations of the compressor. LP switch settings
for pump-down cycles with automatic reset are
also listed in the table above.
Low pressure
On/o cycling (cycle rate
limit)
Danfoss recommends a restart delay timer to limit
compressor cycling. The timer prevents reverse
compressor rotation, which may occur during
brief power interruptions.
The system must be designed in a way that
guarantees a minimum compressor running time
of 2 minutes so as to provide for sucient motor
cooling after start-up along with proper oil return.
Note that the oil return may vary since it depends
upon system design.
There must be no more than 12 starts per hour, a
number higher than 12 reduces the service life of
the motor-compressor unit. A three-minute (180-
sec) time out is recommended.
The discharge gas thermostat accessory kit
includes all components required for installation,
as shown below. The thermostat must be
attached to the discharge line within 150 mm
from the compressor discharge port.
Continuous operation ranges - R407C dew
10
20
30
40
50
60
70
-30 -25 -20 -15 -10 -5 0 5 10 15 20
Evaporating temperature °C
Condensing temperature °C
Example 1
HP2
LP2
LP1
HP1
Example 2


R407C
Working pressure range high side bar (g) 7.8 - 27.4
Working pressure range low side bar (g) 0.7 - 6.6 
Maximum high pressure safety switch setting bar (g) 30
Minimum low pressure safety switch setting bar (g) 0.5
Maximum test pressure bar (g) 30
 LP safety switch shall never be bypassed.  Depends on the models, check on the nameplate
Discharge line
Insulation
Bracket
Thermostat
18 FRCC.PC.017.A2.02
Application Guidelines

System design recommendations
Essential piping design
considerations
Proper piping practices should be employed to
ensure adequate oil return, even under minimum
load conditions with special consideration given
to the size and slope of the tubing coming
from the evaporator. Tubing returns from the
evaporator should be designed so as not to trap
oil and to prevent oil and refrigerant migration
back to the compressor during o-cycles.
If the evaporator lies above the compressor, the
suction line must have a loop at the evaporator
outlet to prevent refrigerant from draining into
the compressor during o-cycles.
If the evaporator were situated below the
compressor, the suction riser must be trapped so
as to prevent liquid refrigerant from collecting at
the thermal bulb location (see g. 1).
When the condenser is mounted at a higher
position than the compressor, a suitably sized
«U»-shaped trap close to the compressor is
necessary to prevent oil leaving the compressor
from draining back to the discharge side of the
compressor during o cycle. The upper loop also
helps avoid condensed liquid refrigerant from
draining back to the compressor when stopped
(see g. 2). The maximum elevation dierence
between the indoor and outdoor section cannot
exceed 8 m. System manufacturers should specify
precautions for any applications that exceed
these limits to ensure compressor reliability.
Piping should be designed with adequate three-
dimensional exibility. It should not be in contact
with the surrounding structure, unless a proper
tubing mount has been installed. This protection
proves necessary to avoid excess vibration, which
can ultimately result in connection or tube failure
due to fatigue or wear from abrasion. Aside from
tubing and connection damage, excess vibration
may be transmitted to the surrounding structure
and generate an unacceptable noise level within
that structure as well (for more information on
noise and vibration, see the section on: "Sound
and vibration management").
General Successful application of scroll compressors is
dependent on careful selection of the compressor
for the application. If the compressor is not correct
for the system, it will operate beyond the limits
given in this manual. Poor performance, reduced
reliability, or both may result.
0.5 % slope,
4 m/s or more
0.5 % slope,
4 m/s or more
U-trap
U-trap, as short as possible
U-trap, as short as possible
max. 4 m
g.1
max. 4 m
8 to 12 m/s
To condenser
Evaporator
Condenser
HP
U-trap
3D exibility
Upper loop
LP
g. 2
19FRCC.PC.017.A2.02
Application Guidelines

System design recommendations
Refrigerant charge limit Danfoss Heat Pump scroll compressors can
tolerate liquid refrigerant up to a certain extend
without major problems. However, excessive
liquid refrigerant in the compressor is always
unfavourable for service life. Besides, the
installation cooling capacity may be reduced
because of the evaporation taking place in the
compressor and/or the suction line instead of the
evaporator. System design must be such that the
amount of liquid refrigerant in the compressor
is limited. In this respect, follow the guidelines
given in the section: “Essential piping design
recommendations” in priority.
Use the tables below to quickly evaluate the
required compressor protection in relation
with the system charge and the application.
More detailed information can be found in the
paragraphs hereafter. Please contact Danfoss for
any deviation from these guidelines.
Notes: for reversible heat pump systems and
other specic applications, please refer to section
"Specic application recommendations".
Reversible heat pump
systems
Transients are likely to occur in reversible heat
pump systems, i.e. a changeover cycle from
cooling to heating, defrost or low-load short
cycles. These transient modes of operation may
lead to liquid refrigerant carryover (or ood back)
or excessively wet refrigerant return conditions. As
such, reversible cycle applications require specic
precautions for ensuring a long compressor
life and satisfactory operating characteristics.
Regardless of the refrigerant charge in the
system, specic tests for repetitive ood back
are required to conrm whether or not a suction
accumulator needs to be installed. A crankcase
heater and discharge gas thermostat are required
for reversible heat pump applications.
These considerations cover the most important
issues in the realm of common applications.
Each application design however should be
thoroughly tested to ensure acceptable operating
characteristics.
Split unit heating mode Repeat the test, but with the system in heating
mode and the outdoor temperature at -18°C
dry bulb. If the sump superheat is not in the
“ACCEPTABLE ZONE” shown in the Flood back
Requirement graph on the next page, a suction
accumulator is required.
Note: for special conditions such as low ambient temperature, low load operation or brazed plate heat exchangers please refer to corresponding sections
Recommended Required No test or additional safeties required
REQREC 
BELOW charge limit ABOVE charge limit
Packaged units No test or additional safeties required O cycle migration test
Liquid ood back test
System with remote heat exchanger O cycle migration test O cycle migration test
Liquid ood back test
REC REQ
REQ
REQ
REQ

Depending on test results, crankcase heaters, Liquid Line Solenoid Valve or suction accumulator must
be applied see below.
Compressor models Refrigerant charge limit (kg)
HHP015-019-021-026 3.6
HHP030-038-045 5.4
20 FRCC.PC.017.A2.02
Application Guidelines