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Specific application recommendations

The use of a suction line accumulator is strongly 
recommended in reversible-cycle applications. 
This because of the possibility of a substantial 
quantity of liquid refrigerant remaining in the 
evaporator, which acts as a condenser during the 
heating cycle. 

This liquid refrigerant can then return to the 
compressor, either flooding the sump with 
refrigerant or as a dynamic liquid slug when the 
cycle  

switches back to a defrost cycle or to normal 
cooling operations.

Sustained and repeated liquid slugging and 
flood back can seriously impair the oil’s ability 
to lubricate the compressor bearings. This 
situation can be observed in wet climates where 
it is necessary to frequently defrost the outdoor 
coil in an air source heat pump. In such cases a 
suction accumulator becomes mandatory.

Suction line accumulator

Defrost and reverse cycle

The Danfoss WSH scroll compressor has the 
ability to withstand a certain amount of liquid 
refrigerant dynamic slug. However we advise that 

the system is unloaded to the minimum capacity 
step for defrost or when the cycle is reversed.

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 quickly 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.

Freezing: When water freezes into ice its volume 
expands which can damage heat exchanger 
walls and cause leaks. During off periods water 
inside heat exchangers could start freezing when 
ambient temperature is lower than 0°C. 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.

Water utilizing systems

29

FRCC.PC.028.A5.02

Application Guidelines

Summary of Contents for WSH 090

Page 1: ...Danfoss scroll compressors WSH090 to WSH184 50 60 Hz R410A Application guidelines http cc danfoss com ...

Page 2: ......

Page 3: ...w pressure protection 19 Cycle rate limit 20 System design recommendations 21 General 21 Essential piping design recommendations 21 Refrigerant charge limit 22 Off cycle migration 23 Liquid flood back 25 Specific application recommendations 26 Low ambient application 26 Low load operation 27 Brazed plate heat exchangers 27 Electronic expansion valve 27 Reversible heat pump systems 27 Water utilizi...

Page 4: ...ow illustrates the entire compression process The centre of the orbiting scroll in grey traces a circular path around the centre of the fixed scroll in black This movement creates symmetrical compression pockets between the two scroll elements Low pressure suction gas is trapped within each crescent shaped pocket as it gets formed continuous motion of the orbiting scroll serves to seal the pocket ...

Page 5: ...e and suction gas and the acoustic level New PTFE spring seal for even lower leaks R410A optimised and dedicated scroll profile Liquid slug protection per suction fitting in upper position Improved lower bearing centring Patented motor centring spacer Patented motor cap WSH range is composed of WSH090 105 120 140 161 184 which is based on current SH range light commercial platform The WSH range be...

Page 6: ... Z C 4 WSH A AL 184 Motor voltage code 3 200 230V 3 60 Hz 4 380 400V 3 50 Hz 460V 3 60 Hz 7 500V 3 50 Hz 575V 3 60 Hz 9 380V 3 60 Hz UL index Nominal capacity in thousand Btu h at 60 Hz R410A ARI conditions Danfoss WSH scroll compressors for R410A are available as single compressors The example below presents the compressor nomenclature which equals the technical reference as shown on the compress...

Page 7: ... 12 34100 116400 10 70 3 19 10 87 133 00 23 12 3 3 67 0 WSH161 13 39000 133100 12 10 3 22 11 00 151 70 26 40 3 3 69 0 WSH184 15 44000 150200 13 65 3 22 11 00 170 30 29 60 3 6 71 5 60Hz WSH090 7 5 27500 93900 8 62 3 19 10 88 88 40 18 60 3 0 58 0 WSH105 9 32700 111600 10 24 3 19 10 90 103 50 21 80 3 3 64 0 WSH120 10 37000 126300 11 38 3 25 11 08 116 90 24 60 3 3 64 0 WSH140 12 41600 142000 12 65 3 2...

Page 8: ... x hole Ø 19 05 1 SH090 2 SH105 120 140 161 except code 3 All dimensions in mm Ø 22 1 Ø 29 2 Ø 35 1 235 2 278 1 94 2 101 1 94 2 101 Equalisation line 15 mm HM 8 bolt Lock washer Flat washer Steel mounting sleeve Rubber grommet Nut WSH090 105 120 140 and 161 except code 3 Flexible grommet 8 FRCC PC 028 A5 02 Application Guidelines ...

Page 9: ...4 x holes Ø19 05 230 230 190 5 190 5 173 1 154 2 159 200 30 30 Ø 22 Ø 35 60 1 SH140 161 code 3 2 SH184 All dimensions in mm Equalisation line 15 mm HM 8 bolt Lock washer Flat washer Steel mounting sleeve Rubber grommet Nut WSH 140 and 161 code 3 and WSH184 Flexible grommet 9 FRCC PC 028 A5 02 Application Guidelines ...

Page 10: ... 4 1 1 8 sleeve This connection must be used to mount an oil equalisation line when two or more compressors are mounted in parallel Schrader Oil equalisation connection Connection details Brazed version Tube ODF Brazed WSH090 Suction 1 1 8 Discharge 7 8 WSH105 120 140 161 184 Suction 1 3 8 Discharge 7 8 WSH 090 105 120 140 161 184 Version AL Suction and discharge connections Brazed Oil sight glass...

Page 11: ...rranty In the same manner cables must be selected in a way to insure that terminal box temperature does not exceed 70 C Terminal box temperature IP rating The 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 objects 5 Dust protected Second numeral level of protectio...

Page 12: ...itions and 10 below nominal voltage 15 C evaporating temperature and 68 C condensing temperature 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 operating Current Compressor model LRA MCC Max Operating current Winding Resistance A A A Ω Motor voltage code 3 200 230V 3ph 60 Hz WSH090 203 43 42...

Page 13: ... of high starting torque surges and costly demand charges from the resultant current spike Upon starting the controller gradually increases the voltage supplied to the motor until full line voltage has been reached All settings such as ramp up time less than 0 5 sec and initial torque are preset and do not require modification Danfoss MCI soft start controller When the control voltage is applied t...

Page 14: ...eliable compressor wiring In case an alternative wiring logic is chosen it is imperative to respect the following rules When a safety switch trips the compressor must stop immediately and must not re start until the tripping condition is back to normal and the safety switch is closed again This applies to the LP safety switch the HP safety switch the discharge gas thermostat and the motor safety t...

Page 15: ...l also be correct Phase sequence and reverse rotation protection Compressor models WSH090 105 120 140 161 184 incorporates an internal reverse vent valve which will react when the compressor is run in reverse and will allow refrigerant to circulate through a by pass from the suction to the discharge Although reverse rotation is not destructive for these models it should be corrected as soon as pos...

Page 16: ...0 Hz WSH models Other approvals certificates Contact Danfoss Products WSH090 to 184 Manufacturer s declaration of incorporation ref Machines Directive 2006 42 EC Contact Danfoss Products WSH090 to 184 Declaration of conformity ref Low voltage Directive 2014 35 EU Contact Danfoss Products Internal free volume without oil litre WSH090 12 4 WSH105 120 140 161 14 3 WSH184 14 6 Products WSH090 105 120 ...

Page 17: ...d the best refrigerant As a near azeotropic mixture refrigerant R410A behaves like an homogeneous substance whereas other zeotropic mixtures such as R407C and other blends suffer a temperature glide during phase change that lessens thermal efficiency and makes them difficult to transfer from a container to another Reduced refrigerant mass flow permitted by a higher heat capacity induce a lower sou...

Page 18: ...ors can be applied from 35 C to 55 C ambient temperature The compressors are designed as 100 suction gas cooled without need for additional fan cooling Ambient temperature has very little effect on the compressor performance Application envelope Compressor ambient temperature POE oil Polyolester oil POE is miscible with HFC s while mineral oil is not but has to be evaluated regarding lubrication a...

Page 19: ...harge pressure exceed the values shown in the table section System pressure test 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 serv...

Page 20: ...oper 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 Note that these two different low pressure switches also require different settings The low pressure pump down switch setting must always be wi...

Page 21: ...To maintain acceptable pressure drops and acceptable minimum gas velocities the refrigerant piping must be reduced in size compared to R22 R407C systems Take care not to create too high pressure drops or since in R410A systems the negative impact of high pressure drops on the system efficiency is stronger than in R22 R407C systems Piping should be designed with adequate three dimensional flexibili...

Page 22: ...high degree of vapour at the expansion device inlet leading to low efficiency Heat exchangers Refrigerant charge limit Danfoss WSH compressors can tolerate liquid refrigerant up to a certain extent 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 ...

Page 23: ...und level The presence of liquid in the crankcase can be easily detected by checking the sump level through the oil sight glass Foam in the oil sump indicates a flooded start A noisy start oil loss from the sump and sump cool down are indications for migration Depending on the amount of migration graduate measures shall be taken Sump heater Liquid line solenoid valve Pump down cycle More detailed ...

Page 24: ...switch can be delayed In this case a low pressure safety switch without any delay timer is mandatory Sump heater The surface sump heaters are designed to protect the compressor against off cycle migration of refrigerant When the compressor is idle the oil temperature in the sump of the compressor must be maintained at no lower than 10 K above the saturation temperature of the refrigerant on the lo...

Page 25: ...nd minimum evaporator load along with the measurement of suction superheat oil sump temperature and discharge gas temperature During operations liquid flood back may be detected by measuring either the oil sump temperature or the discharge gas temperature If at any time during operations the oil sump temperature drops to within 10K or less above the saturated suction temperature or should the disc...

Page 26: ... fans with a head pressure controller will ensure that the fans remain off until the condensing pressure has reached a satisfactory level Variable speed fans can also be used to control the condensing pressure In water cooled units the same can be performed using a water regulator valve that is also operated by head pressure thereby ensuring that the water valve does not open until the condensing ...

Page 27: ...d refrigerant carry over or flood back or excessively wet refrigerant return conditions As such reversible cycle applications require specific precautions for ensuring a long compressor life and satisfactory operating characteristics Regardless of the refrigerant charge in the system specific tests for repetitive flood back are required to confirm whether or not a suction accumulator needs to be i...

Page 28: ...ons with heat recovery or condenser partialisation servo piloted solenoid valve have to be properly sized or associated with a second small valve in parallel in order to avoid quick discharge pressure drops when opening This phenomenon could lead to hammering effects and create constraints on the non return valve integrated in discharge fitting SH180 to 380 Heat pumps frequently utilize high conde...

Page 29: ... a certain amount of liquid refrigerant dynamic slug However we advise that the system is unloaded to the minimum capacity step for defrost or when the cycle is reversed 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 quickly lead to electrical failur...

Page 30: ...compressor sound level to be slightly higher than during normal running WSH scroll compressors exhibit very little increased start up transient sound If a compressor is miswired the compressor will run in reverse Reverse compressor rotation is characterised by an objectionable sound To correct reverse rotation disconnect power and switch any two of the three power leads at the unit contactor Never...

Page 31: ...ibration during operations The use of rubber isolators on the compressor base plate or on the frame of a manifolded unit is very effective in reducing vibration being transmitted from the compressor s to the unit 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 imp...

Page 32: ...rate from the base frame with extensive damage and possible personal injury as a result Never apply force to the terminal box with the intention of moving the compressor as the force placed upon the terminal box can cause extensive damage to both the box and the components contained inside Each WSH compressor is shipped with printed Instructions for installation These instructions can also be down...

Page 33: ...leanliness 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 flux Moisture and air Consequently when building equipment and assemblies the precautions listed in the following paragraphs must be taken Tubing Only use clean and dehy...

Page 34: ...material to flow 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 flux once the joint has been soldered with a wire brush or a wet cloth Remaining flux would cause corrosion of the tubing In addition for discharge connections equipped with a non return valve integrated in disch...

Page 35: ...ressor while it is under vacuum as this may cause internal damage Leak detection Vacuum evacuation and moisture removal Filter driers A properly sized and type of drier is required Important selection criteria include the driers water content capacity the system refrigeration capacity and the system refrigerant charge The drier must be able to reach and maintain a moisture level of 50 ppm end poin...

Page 36: ... 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 5mA WSH scroll compressors are configured with the pump assembly at the top of the shell and the motor below As a result the motor can be partially...

Page 37: ...WSH140 565 470 718 79 WSH161 565 470 718 81 WSH184 565 470 718 84 Compressor models Nbr Length mm Width mm Height mm Gross weight kg Static stacking pallets WSH090 8 1150 950 680 494 2 WSH105 8 1150 950 750 544 2 WSH120 8 1150 950 750 544 2 WSH140 8 1150 950 750 566 2 WSH161 8 1150 950 750 582 2 WSH184 8 1150 950 750 606 2 nbr number of compressors per pack 37 FRCC PC 028 A5 02 Application Guideli...

Page 38: ...120H1026 WSH120 120H1028 120H1030 120H1032 120H1034 WSH140 120H1036 120H1038 120H1040 120H1042 WSH161 120H1044 120H1046 120H1048 120H1050 WSH184 120H1052 120H1054 120H1056 120H1058 Compressor model code no 3 4 7 9 WSH090 120H1013 120H1015 120H1017 120H1019 WSH105 120H1021 120H1023 120H1025 120H1027 WSH120 120H1029 120H1031 120H1033 120H1035 WSH140 120H1037 120H1039 120H1041 120H1043 WSH161 120H104...

Page 39: ...th 1 1 4 rotolock connection Multipack 10 P04 7953007 Solder sleeve P04 1 1 4 Rotolock 3 4 ODF Models with 1 1 4 rotolock connection Industry pack 50 P05 8153012 Rotolock connector P05 1 1 4 Rotolock 7 8 ODF Models with 1 1 4 rotolock connection Multipack 10 P05 7953008 Rotolock connector P05 1 1 4 Rotolock 7 8 ODF Models with 1 1 4 rotolock connection Industry pack 50 P07 8153013 Solder sleeve P0...

Page 40: ...120 140 161 184 Single pack 1 Type Code No Description Application Packaging Pack Size 7750009 Discharge thermostat kit All models Multipack 10 7973008 Discharge thermostat kit All models Industry pack 50 Code no Accessory description Application Packaging Pack size 120Z0388 80W 24V surface sump heater CE and UL WSH090 105 120 140 161 184 Multipack 8 120Z0389 80W 230V surface sump heater CE and UL...

Page 41: ...956005 Gasket for oil sight glass 1 1 8 white teflon All models Multipack 50 8154001 Danfoss Commercial Compressors blue spray paint All models Single pack 1 Type Code No Description Application Packaging Pack Size 120Z0034 Acoustic hood for scroll compressor WSH090 Single pack 1 120Z0035 Acoustic hood for scroll compressor WSH105 120 140 161 except WSH161 140 code 3 Single pack 1 120Z0135 Acousti...

Page 42: ...ion resistance and dielectric strength Leakage current is less than 0 5mA Page 12 Updated Motor voltage code3 WSH105 model in Three phase electrical characteristics Page 16 Pressure equipment directive 2014 68 EU Low voltage directive 2014 35 EU Page 26 Updated Low ambient operations Page 36 Insulation resistance and dielectric strength Leakage current is less than 5mA 42 FRCC PC 028 A5 02 Applica...

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Page 44: ...oned us as distinct variable speed technology specialists Today we operate from engineering and manufacturing facilities spanning across three continents FRCC PC 028 A5 02 Danfoss DCS CC 2016 07 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 cc dan...

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