Danfoss Inverter scroll compressor VRJ Application guide

Application Guidelines
Danfoss Inverter scroll compressor, VRJ
For Residential Applications - R410A
http://danfoss.us.com/
Application Guidelines
Content
Introduction ................................................... 4
Compressor model designation ................... 5
Technical specications ................................ 6
Performance data ..............................................................6
Bearings lubrication .......................................................... 6
Dimensions .................................................... 7
Electrical data, connections and wiring ....... 8
LRA (Locked Rotor Amp)..................................................8
Winding resistance ............................................................8
Wiring connections .......................................................... 9
Approvals and certicates ........................... 10
Approval and certicates ...............................................10
Pressure equipment directive 97/23/EC ..................10
Low voltage directive 73/23/EC, 93/68/EC...............10
Internal free volume .........................................................10
Operating conditions ................................... 11
Refrigerant and lubricants .............................................11
Motor supply.......................................................................11
Compressor ambient temperature .............................11
Application envelope ......................................................12
High and low pressure protection ..............................13
Crankcase heating ............................................................13
Oil return management ..................................................13
On/o cycling (cycle rate limit) ....................................14
Start-up sequence .............................................................14
System design recommendations .............. 15
General ..................................................................................15
Essential piping design considerations .....................15
Refrigerant charge limit .................................................16
Reversible heat pump systems ....................................16
Minimum sump superheat ............................................16
Preventing liquid ood back ........................................16
Water utilising systems ..................................................17
Loss of charge protection...............................................17
Oil level checking and top-up ......................................17
Sound and vibration management ............. 18
Starting sound level .........................................................18
Running sound level ........................................................18
Stopping sound level .......................................................18
Sound generation in a refrigeration system and air
conditioning system ........................................................18
Installation .................................................... 20
System cleanliness ............................................................20
Compressor handling and storage .............................20
Compressor mounting ....................................................20
Compressor holding charge ..........................................20
Tube brazing procedure .................................................20
Brazing material .................................................................20
Compressor connection .................................................21
Vacuum evacuation and moisture removal .............21
Liquid line lter driers ......................................................22
Refrigerant charging ........................................................22
Insulation resistance and dielectric strength ..........22
Compressor replacement after motor burn out ....22
Ordering information and packaging ........ 23
Packaging ............................................................................23
Ordering code numbers .................................................23
3AB141686422149en-US0301
Application Guidelines

Introduction

Scroll compressor components

Danfoss VRJ for residential applications developed by Danfoss is a complete package consisting of a dedicated variable speed compressor, variable speed drive, application controller, electronic expansion valve (EEV), EEV controller and sensors. Three nominal system
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.
sizes are available (3, 4 and 5 TR), based on three compressor models.
These Selection & Application Guidelines focus on the variable speed scroll compressor.

Compressor size

Performance

Variable speed technology oers more exibility in compressor selection than xed speed compressors. Selection of the right variable speed compressor size can be done by dierent methods:
Maximum cooling capacity: select a compressor size that achieves the peak load system cooling capacity demand at its maximum speed.
Nominal cooling capacity: select a compressor size that achieves the nominal system cooling capacity at a rotational speed of 3000-4200 rpm (50-70Hz).
Best Seasonal Eciency Ratio: select a compressor size that achieves the minimum
The Danfoss VRJ compressors referenced in this guide is a fully compliant scroll and actually improves with run time in its early commissioning.
system cooling demand at its minimum speed. Ensure that the compressor is able to cover the peak load system cooling capacity. This selection makes the compressor to run for a maximum of time at part load where the system eciency is highest.
Danfoss 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.
A seventy-two hour run-in is recommended to meet performance expectations.
4 AB141686422149en-US0301
Application Guidelines

Compressor model designation

Nomenclature

Label

Application,
Family
& Refrigerant
VRJ
Application, Family & refrigerant V: Variable speed R: Residential J: R410A, PVE lubricant
Swept Volume
Displacement in cc/rev
Model Variation U: Design optimised for high SEER
Compressor Model no : VRJ044UKNP6
Serial no :
Tech no : VGK46PHA001
LK2500000333
Swept
Volume
028
Model
Variation
U
245 Max Inverter Driven Drive Model: 178L002
LR: 12.0 A MAX OPER: 30.0A Lubricant:PVE / 45 oz/1.33 L
VoltageNMotor
K
MADE IN CHINA
Protection
Equipment
Version
P
Other
Features
6
Other features 6: No other features
Equipment version P: Brased connections,
spade terminals
Motor protection N: No internal motor
protection (protection by drive)
Voltage K: 420V DCL IPM

Serial number

2020
INVERTER PROTECTED
PROTECTED BY DOMESTIC AND FOREIGN PATENTS
1000000052
12345678A 25B
Year code 8 Digit serial number
Month code
Plant assembly line code
5AB141686422149en-US0301
Application Guidelines

Technical specifications

Compressor specications

Performance data

Compressor
model
VRJ028 1.64 51 103 206 240 36 68
VRJ035 2.12 66 133 265 310 45 71
VRJ044 2.65 83 166 332 387 45 71
Conditions
High SEER
conditions
(H)
CHEER
conditions
Heat Pump conditions
SEER
conditions (I)
Swept
volume
cu.in/rev
Compressor model
VRJ028 3 Tons
VRJ035 4 Tons
VRJ044 5 Tons
VRJ028 3 Tons
VRJ035 4 Tons
VRJ044 5 Tons
VRJ028 3 Tons
VRJ035 4 Tons
VRJ044 5 Tons
VRJ028 3 Tons 1800 30 21000 1.75 68.5
VRJ035 4 Tons 1800 30 26800 2.23 69.7
VRJ044 5 Tons 1800 30 34500 2.88 70.9
Min speed 30 Hz 60 Hz Max speed
900 rpm 1800 rpm 3600 rpm 4200 rpm
Nominal Tons
Displacement Oil charge Net weight
oz lb
Compressor speed Compressor capacity
rpm Hz Btu/hr Ton
3600 60 36700 3.06 66.2
4200 70 42700 3.56 64.9
3600 60 46400 3.87 67.6
4200 70 53400 4.45 65.1
3600 60 57800 4.82 68.3
4200 70 68100 5.68 67.0
3600 60 36500 3.04 65.9
4200 70 42300 3.53 64.3
3600 60 46200 3.85 67.3
4200 70 53000 4.42 64.6
3600 60 57900 4.83 68.8
4200 70 68300 5.69 67.5
3600 60 25100 2.09 59.7
4200 70 29300 2.44 58.8
3600 60 31800 2.65 61.0
4200 70 36700 3.06 59.0
3600 60 40200 3.35 62.2
4200 70 47300 3.94 61.2
Compressor
isentropic eciency
Variable speed drive specications

Bearings lubrication

6 AB141686422149en-US0301
Conditions
High SEER
conditions (H)
CHEER
conditions
Heat Pump
conditions
SEER
conditions (I)
Evaporating
Temperature
(°F)
50 115 20 15
45 100 20 15
30 110 20 15
55 100 20 15
Condensing
Temperature
(°F)
For dedicated variable speed drive specications, refer to “Danfoss VRJ Installation and Operation instructions”.
A specic oil pump ensures optimal bearing lubrication at all compressor speeds. This to have sucient bearing lubrication at low speeds as well
Superheat
(°F)
Subcooling
(°F)
as avoid excessive Oil Circulation Ratio (OCR) at high speeds.
Application Guidelines
9.40
All dimensions in inch

Dimensions

VRJ 028 - 035 - 044

4.38
5.06
2.74 - 2.80
7.491 - 7.509
3.750
34°
6.438 - 6.515
31°
45°
4.32
14°
4 x Ø 0.75 - 0.78
3.750
9.40
7.491 - 7.509
14.19
Discharge port 1/2” ODF
2.84 - 2.95
7.76
Suction port 3/4” ODF
9.09
0.42
0.75

Mounting grommet

0.067
1.161
1.614
15.53
5/16” - 18 UNC self tapping
Ø 0.433
Recommended torque for mounting bolts: 8 ft.lbs (±1ft.lbs)
Ø 1.614
7AB141686422149en-US0301
Application Guidelines

Electrical data, connections and wiring

Supply Voltage VRJ compressors must not be connected directly

to the mains supply. They must only be powered through the dedicated Danfoss variable speed drive.
Compressor model Variable Speed Drive Model
VRJ028 176L7000
VRJ035 176L7001
VRJ044 176L7002
Compressor electrical specications

LRA (Locked Rotor Amp)

MCC (Maximum Continuous Current)

Winding resistance

Nominal voltage 208-230V – 1Ph – 60Hz Voltage range 187 – 253 V
Refer to “Danfoss VRJ Installation and Operation instructions” for more details about supply voltage.
Compressor model LRA MCC Winding resistance
A A Ohm
VRJ028 10.2 18 0.255
VRJ035 12 23.5 0.210
VRJ044 12 30 0.210
LRA is the higher average current as measured on a mechanically blocked compressor tested under nominal voltage. LRA is printed on the
VRJ compressors, the LRA value is low because the variable speed drive reacts very rapidly (far below 1 second).
nameplate, according to UL requirements. With
The MCC value is the maximum at which the compressor can be operated in transient
MCC value is measured based on UL conditions (max load) and at low voltage.
conditions and out of the operating envelope. The
VRJ scroll compressors are equipped with an IPM (permanent magnet) motor.
temperature ; If the compressor is stabilised at a dierent value than 77°F, the measured resistance must be corrected with following formula:
a + t
Winding resistance is the resistance between indicated terminal pins at 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.
R
= R
tamb
77°F
t
: reference temperature = 77°F
77°F
: temperature during measurement (°F)
t
amb
: winding resistance at 77°F
R
77°F
: winding resistance at t
R
tamb
a: Coecient a= 390
a + t
amb
77°F
amb
Winding resistance varies strongly with winding
8 AB141686422149en-US0301
Application Guidelines
Electrical data, connections and wiring

Wiring connections

VRJ scroll compressors will only compress gas while rotating counter-clockwise (when viewed from the compressor top).
The drawing shows electrical terminal labelling and should be used as a reference when wiring the compressor.
T1, T2 and T3 of the drive and the compressor must be connected accordingly. Refer to “Danfoss VRJ Installation and Operation instructions” for details and cable sizes.

Terminal cover mounting 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

Terminal cover removal

push
Quick connect spade terminals
P terminal box type
engage the terminal fence. When installing the cover, check that it is not pinching the lead wires.
push

IP rating

Internal motor protection

Phase sequence and reverse rotation protection

push
The compressor terminal box IP rating according to CEI 529 is IP22 for all models. This IP rating is only valid when correctly sized cable glands with the same IP rating are applied.
• First numeral, level of protection against contact and foreign objects 2 protection against object size over 1/2 inch (ngers of similar)
• Second numeral, level of protection against water 2 protection against dripping water when tilted up to 15°
VRJ scroll compressors are not equipped with an internal motor protector. Motor protection is provided by the variable speed drive. All
The compressor will only operate properly in a single direction. If electrical connections are done correctly between the drive and the compressor terminals (compressor and drive terminals T1, T2 and T3 matching), the drive will provide correct phase supply to the compressor, and reverse rotation will be not possible.
motor para-meters are factory preset in order to guaranty optimal locked rotor or overload current protection.
If compressor and drive T1, T2 and T3 terminals are not matching, the compressor can go in reverse rotation. This results in excessive noise, no pressure dierential between suction and discharge, and suction line warming rather than immediate cooling. The compressor can be rapidly severely damaged in these conditions.
9AB141686422149en-US0301
Application Guidelines

Approvals and certificates

Approval and certicates VRJ scroll compressors comply with the following
approvals and certicates.

Pressure equipment directive 97/23/EC

Low voltage directive 73/23/EC, 93/68/EC

Internal free volume

UL (Underwriters Laboratories)
Other approvals / certicates Contact Danfoss
Refrigerating uids Group 2 Category PED I Evaluation module no scope
Manufacturer's declaration of incorporation ref. EC Machines Directives 98/392/CE
Products Internal free volume at LP side without oil (in.3)
VRJ028 - 035 - 044 179
All models
Contact Danfoss
10 AB141686422149en-US0301
Application Guidelines

Operating conditions

Refrigerant and lubricants

General information
PVE
VRJ scroll compressor application range is inuenced by several parameters which need to be monitored for a safe and reliable operation.
These parameters and the main recommendations for good practice and safety devices are explained hereunder:
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
Polyvinyl ether (PVE) is an innovative refrigeration lubricant for HFC refrigerant systems. PVE is as hygroscopic as existing polyolester lubricants (POE), but PVE does not chemically react with water; no acids are formed and compressor evacuation is easier.
Refrigerant and lubricants Motor supply Compressor ambient temperature Application envelope (evaporating
temperature, condensing temperature, return gas temperature)
Additional points could inuence the nal choice:
Environmental considerations
Standardisation of refrigerants and lubricants
Refrigerant cost
Refrigerant availability
The compressor technology applied in Danfoss VRJ scroll compressors in combination with PVE lubricant provides the best possible result in terms of reliability and compressor lifetime.
Residual moisture

Motor supply

Compressor ambient temperature

High ambient temperature
Low ambient temperature
Prior to shipment from the factory, every compressor is dehydrated, evacuated, and charged with dry nitrogen. Maximum residual
VRJ scroll compressors can be operated only connected to the dedicated variable speed drive, at nominal voltages as indicated in “supply
VRJ scroll compressors can be applied from
-13°F to 125°F ambient temperature. The compressors are designed as 100 % suction gas
In case of enclosed tting and high ambient temperature, it is recommend to check the
Although the compressor itself can withstand low ambient temperature, the system may require specic design features to ensure safe
moisture levels are 0.0082 oz. for model VRJ028, and 0.0120 oz. for VRJ035 and VRJ044.
voltage” section. Under-voltage and over-voltage operation is allowed within the indicated voltage range.
cooled without need for additional fan cooling. Ambient temperature has very little eect on the compressor performance
temperature of power wires and conformity to their insulation specication.
and reliable operation. See below sections for recommendations.
11AB141686422149en-US0301
Application Guidelines
Operating conditions

Application envelope

The operating envelope for VRJ scroll compressors is 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:
-40 -36 -32 -28 -24 -20 -16 -12 -8 -4 0 4 8 12 16 20 24
155
145
135
125
115
105
95
85
75
65
2300 - 2850 RPM 2200 - 3300 RPM
2100 - 3750 RPM
1800 - 4200 RPM
1500 - 4200 RPM
1300 - 4500 RPM
1100 - 4500 RPM
Saturated condensing temp. (°F)
55
45
35
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Saturated evaporating temp. (°F)
Maximum discharge gas temperature: +275°F
Suction superheat is dedictated by the minimum sump superheat (see graph p16).
Maximum superheat of 40°F
Minimum and maximum evaporating and condensing temperatures, as per the operating envelopes.
All the below limits, temperatures and speeds, are secured by the parameters in the drive and application controller software’s.
(°C)
2400 RPM Derated
900 - 4500 RPM
70
66
62
58
54
50
46
42
38
34
30
26
22
18
14
10
6
2
(°C)
Maximum discharge gas temperature
12 AB141686422149en-US0301
The discharge temperature depends mainly on the combination of evaporating temperature, condensing temperature and suction gas superheat and speed. Discharge gas temperature should be controlled with an insulated sensor attached to the discharge line, 6 in. from the compressor shell. Maximum discharge gas temperature must not exceed 275°F when the compressor is running within the approved operating envelope.
Refer to “Danfoss VRJ Installation and Operation instructions” for connection details, and to “Sensor Selection Guideline” manual for selection details and technical brochures about temperature sensors.
Application Guidelines
Operating conditions

High and low pressure protection

Pressure settings
High pressure
Low pressure
Suction and discharge pressure transmitters have to be installed and connected to the variable speed drive to ensure the compressor operates within the application envelope described above.
Refer to “Danfoss VRJ Installation and Operation instructions” for connection details, and to “Sensor Selection Guideline” manual for selection details and technical brochures about pressure transmitters.
R410A
Working pressure range high side psig 119 - 645
Working pressure range low side psig 28 - 202
Maximum high pressure safety switch setting psig 653
Minimum low pressure safety switch setting
psig 22
: LP safety switch shall never be bypassed
According to UL requirements, a high pressure safety switch is still mandatory in any system, even with high pressure transmitters connected and used via the variable speed drive.
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 HP switch settings shall not exceed the maximum service pressure of any system components. The
switch must be connected to the service valve
gauge port, which must not be isolated. high-pressure switch can be set to lower values
A low pressure (LP) safety switch is recommended. Deep vacuum operations of a scroll compressor can cause internal electrical arcing and scroll instability. Danfoss 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. Either
the LP safety switch must 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.
High pressure ratio

Crankcase heating

Oil return management

Scroll compressors are machines with xed volume ratio, and operate more eciently near the design pressure ratio. In the extreme, do not exceed a 7.5:1 pressure ratio (absolute discharge pressure to absolute suction pressure)
A crankcase heating function can be provided by injecting a DC current in the motor of the compressor, to keep the compressor warm, and avoid liquid migration during o cycle.
A specic function can be enabled to secure the oil return to the compressor. When the compressor is running at minimum speed for
for extended periods. The Danfoss VRJ scroll
compressor is equipped with an internal pressure
relief valve for protection against blocked
condenser and fan failure conditions.
Refer to “Danfoss VRJ Installation and Operation
instructions” for details.
extended periods, every half hour, speed will be
increased to 2400 rpm for a 80 seconds period.
13AB141686422149en-US0301
Application Guidelines
Operating conditions
On/o cycling (cycle rate limit)

Start-up sequence To ensure correct lubrication of all the

The on/o cycling protection is included in the variable speed drive. There is no need for extra on/o cycling protection.
mechanical parts, VRJ compressors start with a dened ramp-up, and stay at a xed speed
for some seconds. Then the compressor speed increases up to the desired set point according to capacity request.
14 AB141686422149en-US0301
Application Guidelines
U-trap, as short as possible

System design recommendations

General

Essential piping design considerations

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
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.
It is particularly important and critical with variable capacity systems, where very low velocities can be achieved for long periods of time, generating oil return issues.
If the evaporator lies above the compressor, as is often the case in split or remote condenser systems, the addition of a pump-down cycle is strongly recommended. If a pump-down cycle were to be omitted, 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).
beyond the limits given in this manual. Poor
performance, reduced reliability, or both may
result.
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 26 feet. 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” section.
g.1
max. 13 ft
max. 13 ft
0.5 % slope, 13 ft/s or more
U-trap, as short as possible
26 to 40 ft/s
0.5 % slope, 13 ft/s or more
U-trap
Evaporator
To condenser
g. 2
Upper loop
Condenser
HP
U-trap
LP
3D exibility
15AB141686422149en-US0301
Application Guidelines
Saturated suction temp. °F
System design recommendations

Refrigerant charge limit

Reversible heat pump systems

Minimum sump superheat

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
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
The minimum sump temperature is in the range from 10°F to 30°F above saturated suction
Floodback requirement
40
35
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.
require specic precautions for ensuring a long compressor life and satisfactory operating characteristics. Specic tests for repetitive ood back are required to conrm whether or not special system design considerations should be considered.
temperature. Refer to the ood back test criteria.
Preventing liquid ood back
30
25
Acceptable
20
15
Sump superheat, °F
10
5
0
-10 0 10 20 30 40 50 55
Danfoss recommends the use of an electronic expansion valve for all air conditioning and heat pump applications with VRJ compressors. An
Exceptions to the use of EXV’s with Danfoss VRJ must be approved by Danfoss application
engineering. EXV has two key benets: it provides modulating control of the system under varying load conditions, and it protects the compressors from ood back during adverse running conditions.
Unacceptable
16 AB141686422149en-US0301
Application Guidelines
System design recommendations

Water utilising systems Apart from residual moisture in the system

after commissioning, water could also enter the refrigeration circuit during operation. Water in the system shall always be avoided. Not only because it can shortly lead to electrical failure, sludge in sump and corrosion but in particular because it can cause serious safety risks.
Common causes for water leaks are corrosion and freezing.
Corrosion: Materials in the system shall be compliant with water and protected against corrosion.

Loss of charge protection

Oil level checking and top-up

VRJ scroll compressors together with the variable speed drive include a loss of charge protection function. This protection is ensured if pressure
In installations with good oil return and line runs up to 50 ft, no additional oil is required. If installation lines exceed 50 ft, additional oil may be needed. 1 or 2% of the total system refrigerant charge (in weight) can be used to roughly dene the required oil top-up quantity.
Freezing: When water freezes into ice its volume expands which can damage heat exchanger walls and cause leaks. During o periods water inside heat exchangers could start freezing when ambient temperature is lower than 32°F. During on periods ice banking could occur when the circuit is running continuously at too low load. Both situations should be avoided by connecting a pressure and thermostat switch in the safety line.
and temperature sensors are connected to the drive.
Always use oil from new cans.
Top-up the oil while the compressor is idle. Use any accessible connector on the compressor suction line and a suitable pump.
17AB141686422149en-US0301
Application Guidelines

Sound and vibration management

Starting sound level

Running sound level

During start-up transients, it is natural for the compressor sound level to be slightly higher than during normal running. Danfoss scroll
VRJ scroll compressors are designed with optimised discharge ports and wrap geometry
Sound level vs Speed
78
76
74
72
70
68
66
64
62
Sound power level (dBA)
60
58
56
45/130
4200
45/130
3600
Condition (Tsat(suction) / Tsat (discharge) and speed (RPM)
45/100
compressors exhibit very little increased start-up
transient sound.
to reduce the sound level when a compressor is
running.
3600
45/100
2400
45/100
1800
45/100
900

Stopping sound level

Sound generation in a refrigeration system and air conditioning system

Compressor sound radiation
VRJ scroll compressors have very low shutdown sound due to minimal volume of discharge volume to push scrolls in reverse at shutdown.
Typical sound and vibration in refrigeration and air conditioning systems encountered by design and service engineers may be broken down into the following three source categories. Sound radiation: This generally takes an airborne path. Mechanical vibrations: These generally extend
For sound radiating from the compressor, the emission path is airborne and the sound waves are travelling directly from the machine in all directions.
The VRJ scroll compressor is designed to be quiet and the frequency of the sound generated is pushed into the higher ranges, which not only are easier to reduce but also do not generate the penetrating power of lower-frequency sound.
Use of sound-insulation materials on the inside of unit panels is an eective means of substantially
Due to this small re-expansion, there is no
internal break mechanism required to prevent
reverse spin of the scroll set.
along the parts of the unit and structure.
Gas pulsation: This tends to travel through the
cooling medium, i.e. the refrigerant.
The following sections will focus on the causes
and methods of mitigation for each of the above
sources.
reducing the sound being transmitted to the
outside. Ensure that no components capable
of transmitting sound/vibration within the unit
come into direct contact with any non-insulated
parts on the walls of the unit.
Because of the Danfoss unique design of a full-
suction gas & oil cooled motor, compressor body
insulation across its entire operating range is
possible.
18 AB141686422149en-US0301
Application Guidelines
Sound and vibration management
Mechanical vibrations
Speed bypass
Gas pulsation
Vibration isolation constitutes the primary method for controlling structural vibration. VRJ scroll compressors are designed to produce minimal vibration during operations. The use of rubber isolators on the compressor base plate is very eective in reducing vibration being transmitted from the compressor to the unit. Rubber grommets are supplied with all Danfoss compressors. Once the supplied rubber grommets have been properly mounted, vibrations transmitted from the compressor base plate to the unit are held to a strict minimum. In addition, it is extremely important that the frame supporting the mounted compressor be of sucient mass and stiness to help dampen any residual vibration potentially transmitted to the frame. The tubing should be designed so as
If vibrations still occur at some typical frequencies, a speed bypass function is available within the VRJ. This function allows avoiding
The VRJ scroll compressor has been designed and tested to ensure that gas pulsation has been optimised for the most commonly encountered air conditioning pressure ratio. On heat pump installations and other installations where the pressure ratio lies beyond the typical range, testing should be conducted under all expected
to both reduce the transmission of vibrations to other structures and withstand vibration without incurring any damage. Tubing should also be designed for three-dimensional exibility.
During unit development, the complete compressor speed range should be covered, in order to dene if abnormal vibrations occur or not. As ultimate solution, speed bypass can be applied.
For more information on piping design, please see the section entitled “Essential piping design considerations”.
some frequency ranges and avoiding vibrations to occur. Refer to “Danfoss VRJ Installation and Operation instructions” for setting details.
conditions and operating congurations to ensure that minimum gas pulsation is present. If an unacceptable level is identied, a discharge muer with the appropriate resonant volume and mass should be installed. This information can be obtained from the component manufacturer.
19AB141686422149en-US0301
Application Guidelines

Installation

Each VRJ scroll compressor is shipped with printed Instructions for installation.

System cleanliness

Compressor handling and storage

The refrigerant compression system, regardless of the type of compressor used, will only provide high eciency and good reliability, along with a long operating life, if the system contains solely the refrigerant and oil it was designed for. Any other substances within the system will not improve performance and, in most cases, will be highly detrimental to system operations.
The presence of non-condensable substances and system contaminants, such as metal shavings, solder and ux, has a negative impact on compressor service life. Many of these contaminants are small enough to pass through a mesh screen and can cause considerable damage within a bearing assembly. The use of highly hygroscopic PVE oils in R410A compressors requires that the oil be exposed to the atmosphere just as little as possible.
Compressors are provided with a lifting lug. This lug should always be used to lift the compressor. Once the compressor is installed, the lifting lug should never be used to lift the complete installation. The compressor must be handled
System contamination is one of main factors
aecting equipment reliability and compressor
service life. It is important therefore to take
system cleanliness into account when assembling
a refrigeration system.
During the manufacturing process, circuit
contamination may be caused by:
Brazing and welding oxides,
Filings and particles from the removal of burrs in pipe-work,
Brazing ux,
Moisture and air.
Consequently, when building equipment and assemblies, the following precautions must be taken: never drill holes into the pipe-work after installation.
with caution in the vertical position, with a maximum inclination of 15° from vertical. Store the compressor between -30°F and 120°F, not exposed to rain or corrosive atmosphere.

Compressor mounting

Compressor holding charge

Tube brazing procedure

Brazing material

Maximum inclination from the vertical plane, while operating must not exceed 7 degrees. All compressors are delivered with 4 rubber
Each compressor is shipped with a nominal dry nitrogen holding charge between 6 psi and 10 psi, and is sealed with elastomeric plugs. The plugs should be removed with care to avoid oil loss when the holding charge is released. Remove the suction plug rst and the discharge plug
Do not bend the compressor discharge or suction lines or force system piping into the compressor connections, because this will increase
For copper suction and discharge ttings, use copper-phosphorus brazing material. Sil-Fos® and other silver brazing materials are also acceptable.
grommets and metal sleeves. Compressors must always be mounted with these grommets.
afterwards. The plugs shall be removed only just before connecting the compressor to the installation in order to avoid moisture entering the compressor. When the plugs are removed, it is essential to keep the compressor in an upright position to avoid oil spillage.
stresses that are a potential cause of failure. Recommended brazing procedures and material, are described on following page.
If ux is required for the brazing operation, use coated rod or ux core wire. To avoid system contamination, do not brush ux on.
20 AB141686422149en-US0301
Application Guidelines
Installation

Compressor connection

When brazing the compressor ttings, do not overheat the compressor shell, which could severely damage certain internal components due to excessive heating. Use of a heat shield and/or a heat-absorbent compound is highly recommended. For brazing the suction and discharge connections, the following procedure is advised:
Make sure that no electrical wiring is connected to the compressor.
Protect the terminal box and compressor painted surfaces from torch heat damage (see diagram).
Use only clean refrigeration-grade copper tubing and clean all connections.
Purge nitrogen or CO2 through the compressor in order to prevent against oxidation and ammable conditions. The compressor should not be exposed to the open air for extended periods.
Use of a double-tipped torch is recommended.
Apply heat evenly to area A until the brazing temperature is reached. Move the torch to area B and apply heat evenly until the brazing temperature has been reached there as well, and then begin adding the brazing material. Move the torch evenly around the joint, in applying only enough brazing material to ow the full circumference of the joint.
Move the torch to area C only long enough to draw the brazing material into the joint, but not into the compressor.
Remove all remaining ux once the joint has been soldered with a wire brush or a wet cloth. Remaining ux would cause corrosion of the tubing.
Heat shield
C B A
Ensure that no ux is allowed to enter into the tubing or compressor. Flux is acidic and can cause substantial damage to the internal parts of the system and compressor.
The PVE oil used in VRJ compressors is highly hygroscopic and will rapidly absorb moisture from the air. The compressor must therefore not be left open to the atmosphere for a long period of time. The compressor tting plugs shall be removed just before brazing the compressor.
Before eventual unbrazing the compressor or any system component, the refrigerant charge must be removed from both the high and low pressure sides. Failure to do so may result in serious personal injury. Pressure gauges must be used to ensure all pressures are at atmospheric level.
For more detailed information on the appropriate materials required for brazing or soldering, please contact the product manufacturer or distributor. For specic applications not covered herein, please contact Danfoss Commercial Compressors for further information.

Vacuum evacuation and moisture removal

Moisture obstructs the proper functioning of both the compressor and the refrigeration system.
Air and moisture reduce service life and increase condensing pressure, which causes abnormally high discharge temperatures that are then capable of degrading the lubricating properties of the oil. The risk of acid formation is also increased by air and moisture, and this condition can also lead to copper plating. All these phenomena may cause both mechanical
and electrical compressor failures. The typical method for avoiding such problems is a vacuum pump-down executed with a vacuum pump, thus creating a minimum vacuum of 0.02 in Hg (500 µm Hg). Please refer to Bulletin “Vacuum pump down and dehydration procedure”.
Be sure to follow all government regulations regarding refrigerant reclamation and storage.
21AB141686422149en-US0301
Application Guidelines
Installation
Liquid line lter driers A properly sized lter drier is required for all
Danfoss scroll applications. Danfoss recommends DML (100% molecular sieves) driers for HFC refrigerants R410A with PVE oil. For servicing of existing installations where acid formation is present the Danfoss DCL solid core lter driers

Refrigerant charging

Insulation resistance and dielectric strength

It is recommended that system charging be done using the weighed charge method, adding refrigerant to the high side of the system. Charging the high and low sides of a system with gas simultaneously at a controlled rate is also an acceptable method.
Insulation resistance must be greater than 1 megohm when measured with a 500 volt direct current megohm tester.
Each compressor motor is tested at the factory with a high potential voltage (hi-pot) that exceeds the UL requirement both in potential and in duration. Leakage current is less than 0.5 mA.
VRJ scroll compressors are congured with the pump assembly at the top of the shell, and the motor below. As a result, the motor
containing activated alumina are recommended. The drier is to be over sized rather than under sized. When selecting a drier, always take into account its capacity (water content capacity), the system refrigeration capacity and the system refrigerant charge.
Never exceed the recommended system charge mentioned by the unit manufacturer, and never charge liquid to the low pressure side.
can be partially immersed in refrigerant and oil. 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, and should not be cause for concern.
In testing insulation resistance, Danfoss recommends that the system be rst operated briey to distribute refrigerant throughout the system. Following this brief operation, retest the compressor for insulation resistance or current leakage.

Compressor replacement after motor burn out

If there has been a motor burnout follow the evacuation procedure described on previous page. Remove and replace the liquid line lter drier and install a Danfoss type DAS burnout drier of appropriate capacity.
Refer to the DAS drier instructions and technical information on correct use and monitoring of the burnout drier and the liquid line and suction line lter driers.
22 AB141686422149en-US0301
Application Guidelines

Packaging

Single pack

Ordering information and packaging

Compressors are packed individually in a cardboard box. They can be ordered in any quantity. Minimum ordering quantity = 1.
As far as possible, Danfoss will ship the boxes on full pallets of 9 compressors.
Each box contains following accessories:
• 4 grommets
• 4 assemblies of self tapping US thread bolts, washers and sleeves
Industrial pack

Ordering code numbers

Compressor model
Single pack Yes 1 120G0283 120G0291 120G0299 Industrial pack Yes 12 120G0284 120G0292 120G0300
Compressors are not packed individually but are shipped all together on one pallet. They can be ordered in quantities of full pallets only, multiples 12 compressors.
Industrial pack pallet, with mounting hardware, contains following accessories:
• 4 grommets per compressor
• 4 sleeves per compressor
Mounting hardware
included
Qty of compressors
Code number
3 Tons 4 Tons 5 Tons
VRJ028 VRJ035 VRJ044
23AB141686422149en-US0301
Danfoss Commercial Compressors
Danfoss Inverter Scrolls
is a worldwide manufacturer of compressors and condensing units for refrigeration and HVAC applications. With a wide range of high quality and innovative products we help your company to find the best possible energy efficient solution that respects the environment and reduces total life cycle costs.
We have 40 years of experience within the development of hermetic compressors which has brought us amongst the global leaders in our business, and positioned us as distinct variable speed technology specialists. Today we operate from engineering and manufacturing facilities spread across three continents.
Danfoss Turbocor Compressors
Our products can be found in a variety of applications such as rooftops, chillers, residential air conditioners, heatpumps, coldrooms, supermarkets, milk tank cooling and industrial cooling processes.
http://danfoss.us.com
Danfoss Commercial Compressors, BP 331, 01603 Trévoux Cedex, France | +334 74 00 28 29
AB141686422149en-US0301
Danfoss Scrolls
Danfoss Optyma Condensing Units
Danfoss Maneurop Reciprocating Compressors
Secop Compressors for Danfoss
© Danfoss | DCS | 2020.12
Loading...