1 - Introduction
2 - Transportation, storage
3 - Safety measures prior to assembly
4 - Assembly
5 - Leak detection
6 - Vacuum dehydration procedure
7 - Electrical connections
8 - Filling the system
9 - Verification before commissioning
10 - Start up
11 - Troubleshooting
12 - Maintenance
13 - Replacement
14 - User advisory
1 - Introduction
These instructions pertain to Optyma™ Blue
condensing units used for refrigeration purposes.
They are intended to provide necessary information regarding safety features and proper handling
of this product.
Note that this is a general document for the entire range of condensing units; certain details
therefore may not be applicable to the particular
model you purchased. Please keep your manual
and all relevant information handy for future reference.
• Equipment description: condensing units are
available under different configurations. They
incorporate a compressor and a fan-cooled
condenser mounted on a base frame. In addition, they may include a liquid receiver, a pressure switch, a connecting box and service valves.
• Approved list of refrigerants:
- The MCRN and MGRN product line (fitted
with Maneurop® MTZ compressors) can be used
with R404A, R507, R134a, R407C, R407A, R452A,
R448A, R449A.
- The LCQN and LGQN product line (fitted with
Maneurop® NTZ compressors) can be used with
R404A, R452A and R507A.
• Note that Maneurop® compressors are filled
with lubricant before leaving the factory:
- The MTZ series with polyolester oil (ref. 175PZ),
- The NTZ series with polyolester oil (ref. 175Z).
These lubricants must not be mixed with one another.
sure limits displayed on the compressor nameplate or in the application guidelines.
Modifications or alterations to the compressor or receiver (such as brazing on the shell) not
expressly approved by the party responsible for
ensuring compliance could invalidate the user’s
authorization to operate the equipment.
2 - Transportation, storage
• The condensing unit must be handled in the
vertical position (maximum offset from the
vertical: 15°). Should the unit be handled in an
upside-down position, its performance may no
longer be insured.
• Beware that all condensing unit handling must
be carried out with extreme caution to avoid any
shocks. Appropriate and safe lifting equipment
is to be used during handling and unpacking. Be
careful with the condenser’s front surface (note
that the condenser side is indicated on the packaging).
• Any damage noticed on either the packaging
or the product itself upon reception should be
indicated on a Customer Claim addressed to the
shipping company. The same recommendation
applies to all instances when transport instructions have not been fully respected.
• Please review the safety instructions printed on
the cardboard packaging before storage.
• Verify that the condensing unit is never stored
in an ambient temperature of below -35°C
(-31°F) or above 50°C (122°F).
• Ensure that the condensing unit and its packaging are not exposed to rain and/or a corrosive,
flammable atmosphere.
3 - Safety measures prior to assembly
• All installation and servicing is to be performed
by qualified personnel in compliance with all
pertinent practices and safety procedures.
• The condensing unit must be located in a
well-ventilated area; air flow through unit shall
not be restricted in any way (refer to Fig.2). Make
sure that the ambient temperature never exceeds 50°C (122°F) during the off-cycle.
• Use only clean and dehydrated refrigerationgrade copper tubes as well as silver alloy
brazing material.
• Verify that all system components are appropriate (use of refrigerant, etc.), clean and dehydrated before being connected to the completed assembly.
Perform a check on the suction lines: horizontal
sections are to be sloped downwards towards
the compressor. Suction gas velocity must be
high enough to provide for an adequate oil return.This velocity must be within 8 to 12 m/s in
vertical risers. In horizontal pipes, this velocity
can decrease to 4 m/s. The use of U-trap and
double-suction risers may be required on vertical sections, but not in excess of 4 m unless a
second U-trap system has been fitted (refer to
Fig. 3).
Suction line piping must be insulated in order to
minimize the effects of superheating.
• The piping connected to the compressor must
be configured on the basis of a flexible 3-axis design to dampen vibrations and designed in such
a way as to prevent free liquid refrigerant migration and drainage back to the compressor sump.
When installing a liquid receiver or any other
pressure-containing component on the condensing unit, be sure that these components comply with the PED 2014/68/EU.
Make sure the installation is equipped with
high-pressure safety components (e.g. pressure
switch, pressure relief valve) to prevent against the
bursting of pressure-containing components.
• Note that all local and regional regulations and
safety standards, such as EN 378-2:2016, must be
taken into account when designing, connecting
and running the system.
4 - Assembly
The condensing unit’s time of exposure to the
atmosphere during installation shall be held to
a minimum. The condensing unit is fitted with
suction and liquid copper stubs equipped with
shut-off valves to enable connection to the circuit without ingress of air or moisture in the unit.
• Condensing units must only be used for their
designed purpose(s) and within their scope of
application (refer to Fig. 1a,1b).
Condensing units are delivered under nitrogen gas pressure (between 1 and 2 bar) and
hence cannot be connected as it is; please refer
to the «Assembly» section for further details.
Condensing units are not certified for mobile
and explosion-proof applications. Any use of
flammable refrigerant (e.g. hydrocarbons) or air
is also strictly forbidden.
• Under all circumstances, the EN 378-2:2016 (or other
applicable local regulation) requirement must be fulfilled.
When pressure tests are required on the system, they are to be performed by qualified personnel, in paying close attention to potential
pressure-related hazards and heeding the pres-
• For outdoor installations, provide a shelter or
use a Danfoss condensing unit housing.
• Make certain that the condensing unit can be
mounted onto a horizontal plane with a maximum slope of 3°.
• Check that the condensing unit model corresponds to system specifications (capacity, use of
refrigerant, etc.).
• Verify that the power supply corresponds to
compressor and fan motor characteristics (refer
to the condensing unit nameplate for precision).
• Ensure that the refrigerant charging equipment, vacuum pumps, etc. for HFC refrigerant
systems have been specifically reserved for
these refrigerants and never used with other
CFC, HCFC refrigerants.
Opening the shut-off valves before connection
will cause moisture contamination of the compressor lubricant.
• Silent block must be installed under the
condensing unit base frame, as shown in Fig
4, to prevent vibration interference from other
operating equipment or machinery and to reduce vibration transmission to the supporting
structure.
Before opening the compressor connection
fittings, it is mandatory to connect a 1/4” service
hose to the Schrader fitting on the compressor
shell in order to gradually release the nitrogen
holding charge.
• Ensure that no material enters into the system
while cutting the tubing. Moreover, never drill
holes in the pipe work after installation.
FRCC.PI.059.A1.02
Instructions
• Avoid flare-type connections and exercise great
care while brazing (use only state-of-the-art
practices); apply a nitrogen gas flow to prevent
oxidation inside the tubing, especially when
HFC refrigerants are being used. All brazing material is to contain a minimum of 5% silver.
• When brazing, protect the valves and all other
unit components from torch heat damage
(painted surfaces, gaskets, connecting box).
• Note that it is not necessary to remove compressor shut-off valves for connection to the
system, hence no need to replace associated
gaskets.
• Be sure to connect the required safety and control
devices onto compressor shut-off valves or fittings.
• In case of oil return through the Schrader fitting
on the compressor shell, make sure the internal
valve is removed.
5 - Leak detection
Never use oxygen or dry air in order to avoid the
risk of fire or explosion.
• Perform a leak detection test on the complete
system by means of: a dry nitrogen pressure test,
a mixture of nitrogen and the refrigerant to be
used in the system, a helium leak test and/or a
deep vacuum test.
• The test should be long enough in duration to
ensure the absence of any slow leaks in the system.
• Use tools specifically designed for detecting leaks.
• The low side test pressure must not exceed 1.1
x Ps pressure indicated on the compressor nameplate.
• For high side test pressure, do not exceed the pressure indicated on the condensing unit nameplate.
• Whenever the condensing unit is equipped
with suction and liquid shut-off valves, these
valves are to remain in the closed position while
performing the leak test (condensing unit leak
test already performed in the factory).
• Should a leak be discovered, proceed with repair steps and repeat the leak detection.
• When a deep vacuum leak detection test is selected, observe the following:
1) The level to reach is 500 μm Hg.
2) Wait 30 min.
3) If pressure increases rapidly, the system is
not airtight. Locate and repair leaks. Restart the
vacuum procedure, followed by steps 1, 2, etc.
4) If pressure increases slowly, the system
contains moisture inside. Break the vacuum with
nitrogen gas and restart the vacuum procedure,
followed by steps 1, 2, etc.
5) Connect the compressor to the system by
opening the valves.
6) Repeat the vacuum procedure, followed by
steps 1, 2, etc.
7) Break the vacuum with nitrogen gas.
8) Repeat the vacuum procedure, steps 1, 2;
a vacuum of 500 μm Hg (0.67 mbar) should be
reached and maintained for 4 hours. This pres-
sure is to be measured in the refrigeration system, and not at the vacuum pump gauge.
Do not use a megohmeter or apply power to the
compressor while it is under vacuum, as this may
cause motor winding damage (motor burn-out).
Do not use colored leak detection fluids. Do
not use chlorofluorocarbon in leak testing systems designed for HFC fluids.
6 - Vacuum dehydration procedure
Whenever possible (if shut-off valves are present), the condensing unit must be isolated from
the circuit. It is essential to connect the vacuum
pump to both the LP & HP sides, in order to avoid
dead-ending system parts.
Recommended procedure:
1) Once leak detection has been completed,
2) Pull down the system under a vacuum of
500 μm Hg (0.67 mbar).
3) When the vacuum level of 500 μm Hg has
been reached, the system must be isolated from
the pump.
4) A vacuum of 500 μm Hg (0.67 mbar) has
to be reached and maintained for 4 hours. This
pressure is to be measured in the refrigeration
system, and not at the vacuum pump gauge.
If pressure increases, restart the leak-detection
procedure (refer to the «Leak detection» section
of this manual if necessary).
Vacuum pump:
A two-stage vacuum pump with gas ballast
valve (0,04-mbar standing vacuum) shall be
used; its capacity is to be consistent with system
volume.
Never use the compressor as a vacuum pump. It
is recommended to use large-diameter connection lines and to connect these lines to the shutoff valves, rather than to the Schrader connection.
This recommendation allows avoiding excessive
pressure losses.
Moisture level:
At the time of commissioning, system moisture
content may be as high as 100 ppm. During operation, the liquid line filter dryer must reduce this
level to < 20 ppm.
Additional notes:
• To improve moisture removal, the temperature
of the system should not be lower than 10°C.
• A proper vacuum procedure is even more important with HFC and polyolester lubricant than
it has “traditionally” been with HCFC (R22) or CFC
and mineral oil.
• For further details, please refer to TI 3-026.
Do not use a megohmeter or apply power to
the compressor while it is under vacuum, as this
may cause motor winding damage (motor burnout).
7 - Electrical connections
• Make sure the main power supply to the system has been switched off and isolated, in accordance with applicable regulations, before
performing any electrical connection.
• Please refer to Figs 5 and 6 for typical wiring
connections and examine the specific wiring
diagram located in the electrical box cover.
For further details, refer to the condensing unit
guidelines.
• Note that Maneurop® compressors fitted on
condensing units are protected against overheating and overloading by an internal safety motor
protector. However, an external manual reset
overload is recommended for protecting the circuit against over-current.
• The “must trip” value of this overload relay must
be set in accordance with power line sizing and
design and shall never exceed the “A max.” value
stamped on the nameplate.
• On units equipped with an electrical box, all
electrical connections (condenser fan motor,
compressor motor, pressure control switch,
crankcase heater, etc.) have already been wired at
the factory. For single-phase compressors, startand-run capacitors are included in the connecting box.
• The connecting box is equipped with screw type
terminal blocks, for both power and control lines as
well as earth terminals for grounding connections.
• All electrical components must be selected as
per local standards and condensing unit component requirements.
8 - Filling the system
• Before charging the refrigerant, verify that the
oil level is between 1/4 and 3/4 on the compressor oil sight glass and/or ensure that the oil
charge of the original compressor is sufficient as
regards system dimension and piping design:
- An additional quantity of oil might be necessary for line lengths (back and forth) in excess of
20 m.
- In the event additional oil is required, use
only an approved lubricant (refer to the «Introduction» section of this manual).
• Make sure the refrigerant used to fill the system
is compatible with compressor design. Refer to
the «Introduction» section of this manual for an
approved list of refrigerants.
• Compressor switched off: the liquid refrigerant
is charged into the condenser and/or liquid receiver in the liquid phase (compulsory for refrigerant blends).The charge must be asclose to
the nominal system charge as possible in order
to avoid both low pressure operations and excessive superheating at start-up. Throughout
this operation, both compressor service valves
must remain closed.
• To the extent possible, maintain the refrigerant
charge below 2.5 kg per cylinder. Above this limit, install a system, such as a pump-down cycle
or suction line accumulator, to prevent against
liquid flood-back into the compressor.
• Be sure that the refrigerant charge is suitable
for both winter and summer operations.
Ensure that all service valves are in the open
position before start-up. A closed discharge or
suction service valve may cause serious damage
to the compressor and/or compromise safety
device operation, thereby resulting in potential
injury to personnel.
• Check that all safety devices are operational
and properly set (safety pressure switch set
point, mechanical relief valve if necessary, etc.).
Make sure that these devices comply with both
generally - and locally - applicable regulations
and standards (e.g. EN 378-2:2016).
• When using high-pressure switches or relief
valves, the setting must not exceed maximum
service pressure of any system component. Refer to the Application Guidelines for relevant
condensing unit pressure safety limits.
• A low-pressure switch is recommended to
prevent operation under vacuum. Use a minimum setting of 1.2 bar (absolute).
• Verify that all electrical connections are properly fastened and in compliance with local safety
regulations.
• A compressor crankcase heater is factory installed, ensure that it has been energized for a
minimum of 12 hours before initial start-up and/
or during prolonged shutdown periods.
10 - Start up
Never start the compressor in the absence of
a refrigerant charge.
• Do not bypass the LP or any other safety switches during start-up
• Check current draw and voltage levels.
• Monitor the oil sight glass to ensure proper oil
return to the compressor.After 2 to 4 hours of
operations under established conditions, check
the oil level and add oil if necessary (refer to TI
bulletin 3-025).
If oil return continues to perform poorly, further
investigation of the piping design is required.
• In all cases, the application limits of the compressor
must be respected; moreover, high superheat values
lead to high discharge temperatures and decrease
compressor capacity. The maximum discharge temperature is 130°C: operating at a higher temperature
may result in refrigerant decomposition.
• Under steady-state operating conditions, check
refrigerant piping or capillary tubes for abnormal vibrations (refrigeration line movement in
excess of 1.5 mm necessitates corrective actions,
pipe brackets, etc.).
• Ensure that refrigerant flow through the liquid
line sight glass (when mounted) is adequate and
that operating temperatures correspond with
system specifications.
• When needed, refrigerant may be added in the
liquid phase, carefully throttling the refrigerant
on the low-pressure side and as far as possible
from the compressor.The compressor must be
operating during this process.
Do not overcharge the system.
11 - Troubleshooting
• Compressor failure to start: verify that the
compressor is hooked up to the power supply;
check the power lead connections and all suitable capacitors on single-phase models. If these
verifications reveal no abnormality, control the
motor windings with an ohmmeter.
Note: when the internal motor protector has
tripped out, it may take up to several hours to
reset and restart the compressor.
• Compressor failure to build up pressure:
check to make sure that all bypass valves in the
system have not been opened. Also check that
all solenoid valves are in their proper position.
If the internal pressure relief valve is open, the
compressor sump will be warm and the compressor will trip out on the motor protector. If
this happens, it may take up to 2 or 3 hours to
reset and automatically restart the compressor.
• Abnormal running noise on the system:
- Ensure the absence of any liquid flood-back
to the compressor by means of measuring the
return gas superheat and compressor sump
temperature. The sump should be at least 10K
above the saturated suction temperature under
steady-state operating conditions.
- Check that the fans are running free and without vibration.
• The high-pressure switch trips out: check
condenser operations (condenser cleanliness,
fan operations, etc.). If above check out OK, the
problem may be due to either refrigerant overcharging or the presence of a non-condensable
(e.g. air, moisture) in the circuit.
• The low-pressure switch trips out: check evaporator operations (coil cleanliness, fan operations, water flow, water filter, etc.), liquid refrigerant flow and pressure drops (solenoid valve, filter
dryer, expansion valve, etc.), refrigerant charge.
• Low refrigerant charge: the correct refrigerant charge is given by the liquid sight glass
indication, the condenser delta T in relation to
the refrigerant pressure tables (pressure-temperature), the superheat and the sub-cooling, etc.
(if additional charge is deemed necessary, refer
to the «Filling the system» section).
• Compressor maximum short cycling: there
must be a minimum delay of five minutes
between two compressor starts. DCC recommends the compressor should run at least two
minutes after each start, and between each stop
and start must be three minutes standstill. Only
during pump down cycle, the compressor may
run much shorter until the pumpdown pressure
has been reached or when safety devices will
prohibit compressor further operation.
12 - Maintenance
• Proper operations and maintenance of the
condensing units serve to prevent against system-related problems.The following preventive
maintenance checks, to be performed at regular
intervals, are highly recommended:
- Control operating conditions (evaporating
temperature, condensing temperature, compressor discharge temperature, temperature
difference on heat exchangers, superheat,
sub-cooling). These conditions must always remain within compressor operation limits.
- Verify that safety devices are operational and
properly set.
- Check the compressor oil level and quality;
this step may include an acid test, humidity
check, spectrometer analysis, etc. whenever the
oil becomes discolored.
- Ensure that the circuit is leak tight.
- Verify the proper operation of heat exchangers and, if necessary, clean them.
- Check that the fans are running free (without
vibration) and current draw on the compressor
motor as well as proper voltage balance between
phases.
- Note 1: The condenser must be checked at
least once a year for clogging and be cleaned if
deemed necessary. Access to the internal side of
the condenser takes place through the fan panel.
Microchannel coils tend to accumulate dirt on
the surface rather than inside, which makes
them easier to clean than fin-&-tube coils.
- Change the filter dryer when necessary.
- Check that all electrical connections are still
adequately fastened.
- Make sure the condensing unit is clean and
in good working order; verify the absence of rust
or corrosion on components under pressure and
electrical connections.
- Make sure the refrigerant charge is suitable
for both winter and summer operation.
• Ensure that periodic in-service inspections required by local regulations are performed.
- Note 2: Remove surface dirt, leaves, fibers,
etc. with a vacuum cleaner, equipped with a
brush or other soft attachment. Alternatively,
blow compressed air through the coil from the
inside out, and brush with a soft bristle.
Do not use a wire brush. Do not impact or scrape
the coil with the vacuum tube or air nozzle.
13 - Replacement
Precaution must be taken when disconnecting any components, cutting or drilling holes in
the tubing to ensure that no refrigerant under
pressure is present in the system.
The refrigerant shall not be discharged directly into the atmosphere; rather, it must be removed using approved reclamation techniques and
equipment and then safely stored, inaccordance
with applicable legislation.
The presence of refrigerant vapor can displace
air and lead to suffocation. Proper ventilation is
mandatory at all times when servicing the equipment.
A condensing unit component change must be
carried out in compliance with local regulations.
• Make sure that the main power supply has
been switched off.
• Before replacement, it is necessary to determine the cause of failure and implement remedial action. If such analysis and repair are not
performed, repetitive failure may occur. Note
that an oil acidity test always proves helpful indiagnosis when undertaking compressor replacement.
• Check that the replacement component has
the same electrical and refrigeration performance characteristics as the original one.
• Whenever piping needs to be modified, please
refer to the «Safety measures prior to assem-bly» section.
• For further details on replacement steps,refer
to the previous sections of this manual.
Note: In the event of compressor motor failure,
flush and clean the entire circuit before replacing
the compressor in order to remove acids and contaminants. Systematically install a new filter dryer
on the liquid line. Prior to this step (if necessary),
run the system for at least 2 hours with anti-acid
cartridges (in such instances, the installation of a
suction filter might also be required). After an operating period of approximately 2 weeks, check the
level of oil acidity. If the oil acid test proves positive,
drain and replace the oil, replace the anti-acid liquid line filter dryer cartridges and the suction filter
previously installed. Repeat oil and filter dryer replacements until the system is clean and acid-free.
When there is no longer any sign of acidity, replace
the anti-acid cartridges by the standard model and
remove the suction strainer cartridge as required.
14 - User advisory
Insist that all service operations only be performed by qualified personnel.
The condensing unit tubing and compressor
surface temperatures may exceed 100°C (212°F)
and cause severe bodily burns. Special precaution must be taken when working around the
compressor and refrigerant tubing. Moreover, a
compressor in operation can generate very cold
surface temperatures (as low as -45°C / -49°F),
there by exposing personnel to the risk of freezing burns.
Pressure inside the compressor and refrigerant circuit can reach dangerously high levels
(e.g. abnormal operation, fire,…) leading to
personnel injury if suddenly released; therefore,
never drill, weld or cut the compressor shell and
adjacent tubing (release of liquid refrigerant can
cause flash freezing on exposed skin).
Even though fans are fitted with safety guard
it is recommended not to work on condenser
while fans are running.
Be aware that the product warranty may be
deemed null and void in the following cases:
• Modifications to the unit, unless approved by
Danfoss Commercial Compressors, absence
of nameplate, broken or dented components,
shock marks, etc...
• Compressor opened by the customer or returned unsealed (i.e. open discharge or suction
ports),
• Presence of rust or water inside the condensing
unit circuit,
• Addition of leak-detection fluid in the compressor lubricant,
• Use of a refrigerant or lubricant not approved
by Danfoss Commercial Compressors.,
• Any deviation from recommended instructionspertaining to installation, application or maintenance,
• Use in mobile applications (boats, trains, trucks,etc.) or under explosive atmospheric conditions.
The date of production of the condensing unit
is indicated on the nameplate. Ensure that the
model and serial number information is always
transmitted with any claim filed regarding this
product.