Instructions
© Danfoss | DCS (CC) | 2018.03  | 3
8510196P04H - FRCC.PI.049.A4.02
1 - Introduction
These instructions pertain to the Maneurop® MT, 
MTZ,VTZ & NTZ compressors used for refrigera-
tion systems. They provide necessary informa-
tion 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 packa-
ging to rain or corrosive atmosphere.
3 – Safety measures before assembly
 Never use the compressor in a ammable at-
mosphere.
 •  The compressor ambient temperature may 
not exceed 50°C 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 MTZ,VTZ or NTZ, use equip-
ment specically reserved for HFC refrigerants 
which was never used for CFC 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.
4 - Assembly
 •  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 tech-
nique 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.
5 – Leak detection
 Never pressurize the circuit with oxygen or 
dry air. This could cause re or explosion.
  •   Do not use dye for leak detection.
  •   Perform a leak detection test on the complete 
system.
 •   The low side test pressure must not exceed 25 
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.
 •   Evacuate the system to a pressure 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.
7 – Electrical connections
 •   Switch o and isolate the main power supply. 
See overleaf for wiring details.
 •  The compressor is protected against excess 
current and temperature by an internal over-
load protector. Follow local regulations regar-
ding power line protection. The compressor 
must be connected to earth.
  •   All electrical components must be selected as per 
local standards and compressor requirements.
8 – 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.
 •   Keep the refrigerant charge below 2.5 kg per 
compressor cylinder 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 to avoid overlling.
9 – 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 
0.1 bar.
 •  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 shutdown.
10 – Start-up
  •   All service valves must be in the open position.
  •   Balance the HP/LP pressure.
 •  Energize the compressor. It must start 
promptly. If it does not, switch it o 
immediately. Possible single phase miswiring 
can cause burn-out within seconds.
  •   If the compressor does not start, check wiring 
conformity and voltage on terminals.
 •   If the internal overload protector trips out, it 
must cool down to 60°C to reset. Depending 
on ambient temperature, this may take up to 
several hours.
11 – Check with running compressor
  •   Check current draw and voltage.
 •  Check suction superheat to reduce risk of 
slugging.
  •   When a sight glass is provided observe the oil 
level at start and during operation to conrm 
that the oil level remains visible.
  •   Respect the operating limits as printed overleaf.
  •   Check all tubes for abnormal vibration. Move-
ments in excess of 1.5 mm require corrective 
measures such as tube brackets.
 •  When needed, additional refrigerant in the 
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 the 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 inju-
ry.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.
 •   Conrm that the system is operating in a way 
consistent with previous maintenance re-
cords and ambient conditions.
 •  Check that all electrical connections are still 
adequately fastened.
 •   Keep the compressor clean and verify the ab-
sence of rust and oxidation on the compres-
sor shell, tubes and electrical connections.
13 - Warranty
Always transmit the model number and serial nu-
mber with any claim led regarding this product.
The product warranty may be void in following 
cases:
  •   Absence of nameplate.
 •  External modications; 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 instruc-
tions pertaining to installation, application or 
maintenance.
  •   Use in mobile applications.
  •   Use in explosive atmospheric environment.
 •  No model number or serial number trans-
mitted with the warranty claim.
14 – Disposal
Danfoss recommends that compressors 
and compressor oil should be recycled 
by a suitable company. 
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 specications already agreed. All trade-
marks in this material are property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.