FRCC.PI.036.A2.02
1- 8510278P01B
© Danfoss | DCS (CC) | 2016.04
Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products
already on order provided that such alterations can be made without subsequential changes being necessary in specifications already agreed.
All trademarks in this material are property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.
Danfoss A/S, 6430 Nordborg, Denmark
1 – Introduction
These instructions pertain to the Danfoss scroll
compressors MLZ/MLM116 scroll compressors
used for refrigeration systems. They provide
necessary information regarding safety and
proper usage of this product.
2 – 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 -35°C and 50°C.
•
Don’t expose the compressor and the
packaging to rain or corrosive atmosphere.
3 – Safety measures before assembly
Never use the compressor in a flammable
atmosphere.
• The compressor ambient temperature may not
exceed 50°C during off-cycle.
• Mount the compressor on a horizontal flat
surface with less than 3° slope.
• Verify that the power supply corresponds to
the compressor motor characteristics (see
nameplate).
• When installing MLZ/MLM116, use equipment
specifically reserved for HFC refrigerants 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
flexible in 3 dimensions to dampen vibrations.
4 – Assembly
•
In parallel assemblies of MLZ/MLM116 the
compressor requires a rigid mounting on the
rails. Use the rigid spacers from mounting kit
777045 to connect compressor to rails. For rail
and frame connection, use rubber grommet from
manifolding kit (7777041 for tandem and quadro
/ 7777049 for trio). Never use rigid connection
between rail and frame.
• 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 flow.
•
Connect the required safety and control
devices. 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 3/4” rotolock
110 Nm
2 1/4” rotolock
130 Nm.
5 – Leak detection
Never pressurize the circuit with oxygen or
dry air. This could cause fire or explosion.
• Pressurize the system on HP side first 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 difference 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 :
Models
LP side
HP side
MLZ/MLM116
25 bar
32 bar
• When a leak is discovered, repair the leak and
repeat the leak detection.
6 – 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
500µm 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.
7 – Electrical connections
• Switch off and isolate the main power supply.
See overleaf for wiring details.
• All electrical components must be selected as per
local standards and compressor requirements.
• Refer to page 2 for electrical connections details.
•
The Danfoss scroll compressors scroll
compressor only works correctly in one
rotation direction. Line phases L1, L2, L3
must absolutely be connected to compressor
terminals T1, T2, T3 to avoid reverse rotation.
• Please make sure M1/M2 is connected to OEM
controller and L/N is connected to ouside
power supply, otherwise, there will be no
motor protection.
• Use ø 4.8 mm (3/16”) screws and ¼” ring
terminals for the power connection. Fasten
with 3 Nm torque.
• The thermostat connection (if present) is a ¼”
AMP-AWE spade connector.
• The compressor must be connected to earth
with the 5 mm earth terminal screw.
8 – Filling the system
• Keep the compressor switched off.
• 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 difference
could cause internal compressor damage.
•
Keep the refrigerant charge below the
indicated charge limits if possible. Above this
limit; protect the compressor against liquid
flood-back with a pump-down cycle or suction
line accumulator.
• Never leave the filling cylinder connected to
the circuit.
Compressor models Refrigerant charge limit (kg)
MLZ/MLM116
13.5
9 – Verification before commissioning
Use safety devices such as safety pressure
switch and mechanical relief valve in compliance
with both generally and locally applicable
regulations and safety standards. Ensure that
they are operational and properly set.
Check that the settings of high-pressure
switches 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 MLM116: 0.5 bar g. Minimum setting for
MLZ116 : 0.7 bar g.
•
Verify that all electrical connections are
properly 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 shutdown for
belt type crankcase heaters (6 hours for surface
sump heaters).
10 – Start-up
• Never start the compressor when no refrigerant
is charged.
• All service valves must be in the open position.
• Balance the HP/LP pressure.
• Energize the compressor. It must start promptly.
If the compressor does not start, check wiring
conformity and voltage on terminals.
•
Eventual reverse rotation can be detected
by following phenomena; the compressor
doesn’t build up pressure, it has abnormally
high sound level and abnormally low power
consumption. In such case, shut down the
compressor immediately and connect the
phases to their proper terminals. MLZ/MLM116
scroll compressors scroll compressors are
protected against reverse rotation by the
external electronic protection module. They
will shut off automatically.
11 – Check with running compressor
• Check current draw and voltage.
• Check suction superheat to reduce risk of slugging.
• Observe the oil level in the sight glass for about 60
minutes to ensure proper oil return to the compressor.
• Respect the operating limits.
•
Check all tubes for abnormal vibration.
Movements in excess of 1.5 mm require
corrective measures such as tube brackets.
•
When needed, additional refrigerant in liquid
phase may be added in the low-pressure side as far
as possible from the compressor. The compressor
must be operating during this process.
• Do not overcharge the system.
• Never release refrigerant to atmosphere.
• Before leaving the installation site, carry out
a general installation inspection regarding
cleanliness, noise and leak detection.
• Record type and amount of refrigerant charge
as well as operating conditions as a reference
for future inspections.
12 – Maintenance
Internal pressure and surface temperature
are dangerous and may cause permanent injury.
Maintenance operators and installers require
appropriate skills and tools. Tubing temperature
may exceed 100°C and can cause severe burns.
Ensure that periodic service inspections to
ensure system reliability and as required by local
regulations are performed.
To prevent system related compressor
problems, following periodic maintenance is
recommended:
• Verify that safety devices are operational and
properly set.
• Ensure that the system is leak tight.
• Check the compressor current draw.
• Confirm that the system is operating in a way
consistent with previous maintenance records
and ambient conditions.
• Check that all electrical connections are still
adequately fastened.
•
Keep the compressor clean and verify the
absence of rust and oxidation on the compressor
shell, tubes and electrical connections.
13 - Warranty
Always transmit the model number and serial
number with any claim filed regarding this product.
The product warranty may be void in following
cases:
• Absence of nameplate.
• External modifications; in particular, drilling,
welding, broken feet and shock marks.
• Compressor opened or returned unsealed.
• Rust, water or leak detection dye inside the
compressor.
• Use of a refrigerant or lubricant not approved
by Danfoss.
• Any deviation from recommended instructions
pertaining to installation, application or
maintenance.
• Use in mobile applications.
• Use in explosive atmospheric environment.
• No model number or serial number transmitted
with the warranty claim.
14 – Disposal
Danfoss recommends that compressors
and compressor oil should be recycled
by a suitable company at its site.
L N S1 S2 M1 M2
L1 L2 L3
Black Blue Brown
Phase sequence input
Internal control contact
Safety
circuit
Thermistor
connection
Module power
L N
M1 M2
