Instructions
6 | AN245986497033en-000801 - 8510197P05J
© Danfoss | DCS (CC) | 2020.10
5 – Handling and storage
 •  Handle the compressor with care. Use the 
dedicated handles in the packaging. Use the 
compressor lifting lug and use appropriate 
and safe lifting equipment.
 •  Store and transport the compressor in an 
upright position.
 •   Store the compressor between Ts min and Ts 
max values for LP side indicated on compres-
sor nameplate. 
 •   Don’t expose the compressor and the packa-
ging to rain or corrosive atmosphere.
6 – Safety measures before assembly
 Never use the compressor in a ammable at-
mosphere.
 •  Check before assembly that the compressor 
does not show any obvious signs of deteriora-
tion that could have occurred during inappro-
priate transportation, handling or storage.
 •  The compressor ambient temperature may 
not exceed Ts max value for LP side indicated 
on compressor nameplate during o-cycle.
 •  Mount the compressor on a horizontal at 
surface with less than 3° slope.
 •  Verify that the power supply corresponds to 
the compressor motor characteristics (see  
nameplate).
 •  When installing DSH, SH, WSH or SZ, use 
equipment specically reserved for HFC re-
frigerants which was never used for CFC or 
HCFC refrigerants.
 •   Use clean and dehydrated refrigeration-grade 
copper tubes and silver alloy brazing material.
  •   Use clean and dehydrated system components.
  •   The piping connected to the compressor must be 
exible in 3 dimensions to dampen vibrations.
7 – Assembly
 •   The compressor must be mounted on rails or 
chassis according to Danfoss recommenda-
tions described in related product guidelines 
(type of spacer, tightening torques).
 •  Slowly release the nitrogen holding charge 
through the schrader port.
 •  Remove the gaskets when brazing rotolock 
connectors.
  •   Always use new gaskets for assembly.
 •  Connect the compressor to the system as 
soon as possible to avoid oil contamination 
from ambient moisture.
  •   Avoid material entering into the system while 
cutting tubes. Never drill holes where burrs 
cannot be removed.
 •  Braze with great care using state-of-the-art 
technique and vent piping with nitrogen gas 
ow.
 •  Connect the required safety and control de-
vices. When the schrader port is used for this, 
remove the internal valve.
 •  Do not exceed the maximum tightening 
torque for rotolock connections: 
Rotolock connections Tightening torque
1" rotolock 80 Nm
1 1/4 " rotolock 90 Nm
1 3/4" rotolock 110 Nm
2 1/4" rotolock 145 Nm.
8 – Leak detection
 Never pressurize the circuit with oxygen or 
dry air. This could cause re or explosion.
 •   SM 084 to 185, SY 380, SZ 084 to 185, SZ 380, 
DSH / SH / WSH 090 to 184: Pressurize the 
system on HP side rst and then on LP side. 
Never let the pressure on LP side exceed the 
pressure on HP side with more than 5 bar. 
Such pressure dierence could cause internal 
compressor damage.
  •   Do not use dye for leak detection.
  •   Perform a leak detection test on the complete 
system.
 •  The test pressure must not exceed 1.1 x PS 
value for LP side and PS value for HP side indi-
cated on compressor nameplate.
 •   When a leak is discovered, repair the leak and 
repeat the leak detection.
9 – Vacuum dehydration
 •  Never use the compressor to evacuate the 
system.
  •   Connect a vacuum pump to both the LP & HP 
sides.
 •   Pull down the system under a vacuum of 500 
µm Hg (0.67 mbar) absolute.
 •   Do not use a megohmmeter nor apply power 
to the compressor while it is under vacuum as 
this may cause internal damage.
10 – Electrical connections
 •   Switch o and isolate the main power supply. 
See overleaf for wiring details.
  •   All electrical components must be selected as 
per local standards and compressor require-
ments.
 •  Refer to section 4 for electrical connections 
details.
 •  The Danfoss scroll compressors only works 
correctly in one rotation direction. Line 
phases L1, L2, L3 must absolutely be connec-
ted to compressor terminals T1, T2, T3 to 
avoid reverse rotation.
 •  According to compressor model, electrical 
power is connected to the compressor termi-
nals either by  4.8mm (10-32) screws or  by M5 
studs and nuts . In both cases use appropriate 
ring terminals, fasten with 3Nm torque.
 •   The thermostat connection (if present) is a ¼” 
AMP-AWE spade connector.
 •  The compressor must be connected to ear-
th with the 5 mm earth terminal screw. The 
maximum torque is 4Nm.
11 – Filling the system
  •   Keep the compressor switched o.
 •  Fill the refrigerant in liquid phase into the 
condenser or liquid receiver. The charge must 
be as close as possible to the nominal system 
charge to avoid low pressure operation and 
excessive superheat. Never let the pressure on 
LP side exceed the pressure on HP side with 
more than 5 bar. Such pressure dierence 
could cause internal compressor damage.
 •  Keep the refrigerant charge below the in-
dicated charge limits if possible. Above this 
limit; protect the compressor against liquid 
ood-back with a pump-down cycle or suc-
tion line accumulator.
 •  Never leave the lling cylinder connected to 
the circuit.
Compressor models Refrigerant charge 
limit (kg)
SM/SZ 084, 090, 100 8.5
SM/SZ 110, 120 10
SM 112, 124, 147 , SZ147 7.9
SM/SZ 115, 125 11
SM/SZ 148, 160, 161 12.5
SM/SZ 175, 185 13.5
SY/SZ 240 16
SY/SZ 380 20
DSH / SH / WSH 090 5.9
DSH / SH / WSH 105, 120, 
140, 161, 184
7.9
SH 180, 240, 295, 300 13.5
DSH 240,295 15
SH 380 14.5
SH 485, DSH600,  
DSH 381,485
17
12 – Verification before commissioning
 Use safety devices such as safety pressure 
switch and mechanical relief valve in compliance 
with both generally and locally applicable regu-
lations and safety standards. Ensure that they 
are operational and properly set. 
 Check that the settings of high-pressure swit-
ches and relief valves don’t exceed the maximum 
service pressure of any system component.
 •  A low-pressure switch is recommended to 
avoid vacuum operation. Minimum setting 
for SM/SY/SZ: 0.5 bar g. Minimum setting for 
DSH / SH / WSH: 1.7 bar g.
 •  Verify that all electrical connections are pro-
perly fastened and in compliance with local 
regulations.
 •   When a crankcase heater is required, it must 
be energized at least 12 hours before initial 
start-up and start-up after prolonged shut-
down for belt type crankcase heaters (6 hours 
for surface sump heaters).
13 – Start-up
 Never operate the compressor without the 
electrical box cover tted.
 •   Never start the compressor when no refrige-
rant is charged.
 •  All service valves must be in the open posi-
tion.
  •   Balance the HP/LP pressure.
  •   Energize the compressor. It must start promp-
tly. If the compressor does not start, check wi-
ring conformity and voltage on terminals.
 •  Eventual reverse rotation can be detected 
by following phenomena; the compressor 
doesn’t build up pressure, it has abnormal-
ly high sound level and abnormally low 
power consumption. In such case, shut down 
the compressor immediately and connect 
the phases to their proper terminals. Most 
Danfoss scroll compressors are protected 
against reverse rotation either by an internal 
reverse rotation protection or by the exter-
nal electronic protection module. They will 
shut o automatically. Only SM 112, 124, 147, 
SZ147 have no reverse rotation protection. 
Prolonged reverse rotation will damage these 
compressors.
 •  If the internal overload protector trips out 
(SM/SZ 084, 090, 100, 110, 112, 120, 124, 147,