REMKO ML 351, ML, ML 251, ML 521, ML 681 Operation,technology,spare Parts

REMKO ML

ML 261, ML 351, ML 521, ML 681

Wall-mounted split design air conditioning unit

Operation · Technology · Spare parts

Edition GB – T07

Contents

Safety notes

Environmental protection and recycling

Warranty

Transportation and packaging

Description of the equipment

Operation

Shutdown

Care and maintenance

Troubleshooting and customer service

Installation instructions for qualified personnel

Installation

Tightness check

Condensation connection

4

4

4

5

5

6-12

12

12-13

14-15

15-18

18-19

20

20

Electrical connection

Electrical connection diagram

Electrical circuit diagram

Before commissioning

Adding refrigerant

Commissioning

Unit dimensions

Exploded view

Spare parts list

Technical data

Carefully read this operating manual prior to commissioning or
using the equipment!

20-21

21

22

23

23

23-24

24

25-26

25-26

27

Made by REMKO

This manual is an integral part of the unit and must be stored at the
installation location or in the immediate vicinity.

Subject to modifications; No liability accepted for errors or misprints!

3

REMKO ML

Safety notes

Carefully read this manual before
starting the unit for the first time. It
contains useful tips and notes as
well as hazard warnings to prevent
injury or material damage . Non­observance of this manual may
endanger persons, the environment
as well as the equipment itself and
will void any claims for liability.

■ Store this manual and the

refrigerant datasheet in the
vicinity of the unit.

■ The unit should only be set

up and installed by qualified
personnel.

■ The setup, connection and

operation of the unit and
its components must be in
accordance with the operating
conditions stipulated in this
manual and comply with all
applicable local regulations.

■ Units designed for mobile use

should be safely set up on a
suitable floor and in a vertical
position. Units designed for
stationary use should only be
operated in their permanently
installed state.

■ It is prohibited to make

modifications or changes to
equipment or components
supplied by REMKO as this may
cause malfunctions.

■ Equipment and components

should not be operated in areas
where there is a heightened
damage risk. Observe the
minimum clearances.

■ The electrical supply should

be adapted to fulfil the
requirements of the unit.

■ The operational safety of

equipment and components is
only assured providing they are
used as intended and in a fully
assembled state. Safety devices
should not be modified or
bypassed.

■ Do not operate equipment

or components with obvious
defects or signs of damage.

■ All housing parts and openings,

e.g. air inlets and outlets, must
not be blocked by foreign items,
fluids or gases.

■ The equipment and components

must be kept a safe distance
from inflammable, explosive,
combustible, agressive and dirty
areas or atmospheres.

■ Persons coming into contact

with equipment parts may suffer
burns or injury.

■ Installation, repair and

maintenance work should only
be carried out by authorised
specialists. Inspection and
cleaning can be performed
by the operator providing the
equipment is not under voltage.

■ Take appropriate hazard

prevention measures when
performing installation, repair or
maintenance work or cleaning
the equipment.

■ The equipment and components

should not be exposed to any
mechanical stresses, extreme
levels of humidity or direct
exposure to sunlight.

Environmental
protection
and recycling

Disposal of packaging

All products are carefully packaged
using environmentally friendly
materials prior to transportation.
Make a valuable contribution to
reducing waste and sustaining
raw materials. Only dispose of
packaging at approved collection
points.

Disposal of
old equipment

Equipment manufacture is subject
to continuous quality control. Only
high-quality materials are used, the
majority of which can be recycled.
Help protect the environment by
only disposing of old equipment in
accordance with local regulations
and in an environmentally safe
manner, e.g. through authorised
disposal and recycling specialists or
at collection points.

Warranty

In order to make warranty claims,
it is essential that the the ordering
party or their representative
complete and return the "certificate
of warranty" and commissioning
report to REMKO GmbH & Co. KG
at the time when the equipment
was purchased and commissioned.
The warranty conditions are
detailed in the "General terms
and conditions“. The contractual
parties can also agree additional
terms beyond the scope of the
above. In this case, first contact the
contractual partner.

4

Transportation and
packaging

The equipment was shipped in
sturdy packaging. Immediately
check the equipment on delivery
and make a note of any damage or
missing parts on the delivery note.
Inform the forwarding agent and
contractual partner.
Warranty claims at a later date will
not be accepted.

Schematic of exterior refrigerant circuit

Liquefier fan

M

Reverse flow valve

Compressor

Connection for
pressure gauge

M

Capillary tube flow regulatorFilter dryerLiquefier

Connection valve
Suction pipe

Connection valve
Injection pipe

Description of the
equipment

The ML 261-681 air conditioning

equipment consists of an REMKO
ML...AT outdoor component and
an ML...IT interior unit.

The outdoor component serves to

output the heat extracted by the
interior unit from the room being
cooled.
In heating mode, the interior unit
dissipates the heat extracted by
the outdoor component.

The outdoor component can be

installed outdoors or indoors. The
latter requires the fulfilment of
certain conditions. The indoor unit
is designed for interior use and
should be mounted high up on a
wall. It is operated by an infrared
remote control.

The outdoor component comprises

a refrigerant and compressor,
liquefier with fins, liquefier
fan, reverse flow fan and flow
regulator. The outdoor component
is controlled by the regulator in the
indoor unit.

The indoor unit comprises a finned

vaporiser, vaporiser fan, controller
and condensation tray.

Schematic of refrigerant circuit in indoor unit

Vaporiser fan

Vaporiser

System layout

Indoor area

Indoor unit

Condensation pipe

Outdoor area

Outdoor
component

Connection to

suction pipe

Connection to injection pipe

Control cable

Injection pipe

Mains cable

Stop valve

Suction pipe

Winter controllers, floor and wall
brackets, refrigerant pipes and
condensation pumps are also
available as accessories.

Liquefier fan

Condensation pipe

Refrigerant pipes are used to connect the indoor unit to the outdoor
component.

5

REMKO ML

Operation

The indoor unit is easy to operate using an infrared remote control. This is supplied as standard. The indoor unit
beeps to acknowledge the correct transmission of data. If it is not possible to program the indoor unit using the
remote control, it can also be manually operated.

Manual operation

The indoor unit can also be
started manually. Open the air inlet
guard. Press the button behind the
guard to activate automatic mode.
The following settings apply to
manual mode:

Cooling mode: last setting
Fan speed: AUTO
Heating mode : last setting
Fan: AUTO

Pressing any button on the infrared
remote control interrupts manual
operation.

Display on indoor unit

The display is lit according to the settings.

Display on indoor unit

Swing mode

Cooling
mode

Automatic mode

Sleep function

Unit of temperature

Display

Used to display

coded error

messages, room and

target temperature

Heating mode

Dehumidifying mode

Timer

Fan speed

Infrared remote control

The infrared remote control can
send the programmed settings
from a distance of 6 m to the
receiver on the indoor unit. Data
will only be received correctly if
the remote control is pointed at
the receiver and no objects are
obstructing the transmission path.

First of all, insert the batteries
(two type AAA) supplied with
the remote control. Remove the
cover on the battery compartment
and insert the batteries. Take into
account the correct polarity (see
markings).

Max. distance 6 m

max. 6 m

CAUTION

Errors are displayed in
coded format
(see chapter on trouble­shooting and customer service)

TIP

Help save on energy consump­tion in stand-by mode! If the
device, system or component
is not in use, we recommend
disconnecting the power sup­ply. Components with a safety
function is excluded from our
recommendation!

NOTE

Immediately replace flat batteries
with a new set, otherwise there is
a risk of leakage.
It is recommended that the
batteries are removed if the
equipment is shut down for long
periods

6

Buttons on the remote control

Buttons on the remote control

"ON/OFF" Button

Press this button to start the
equipment.

"TOO HOT" Button

Press this button to reduce the

desired temperature to a value
as low as 16 °C.

"TOO COLD" Button

Press this button to increase the

desired temperature to a value
as high as 31 °C.

"MODE" Button

Press this button to select the
operating mode. The indoor unit
has 4 modes:

1. Automatic mode
In this mode the equipment can
be running in cooling or heating
mode.

2. Cooling mode
In this mode the warm room
air is cooled to the required
temperature.

3. Dehumidfying mode
In this mode the room is
mainly dehumidfied, the set
temperature is maintained.

4. Heating mode
In this mode the warm room
air is heated to the desired
temperature.

"FAN" Button

Press this button to set the

required fan speed. 4 levels
are available: Automatic, high,
medium and low fan speed.

"FINS" Button

Press this button to adjust

the position of the outlet
fins. 5 fixed positions and
an oscillating function are
available.

"SLEEP" Button

Pressing this button will

automatically increase or
decrease the target temperature
by 1 °C every hour in cooling
and heating mode respectively.

"SWING" Button

This button activates the

oscillating fin function
to provide improved air
distribution in the room.

"TIMER ON" Button

Press this button to set an
automatic equipment switch-on
time in the next 24 hours.

"TIMER OFF" Button

Press this button to set an

automatic equipment switch-off
time in the next 24 hours.

"HR" Button

Press this button to set the

hours.

"MIN" Button

Press this button to set the

minutes.

"RESET button"

(in battery compartment)

Press this button to reset the

remote control to its factory
default configuration.

"CLOCK" Button

(in battery compartment)

Press this button to activate

clock setting mode.

"DISPLAY" Button

Press this button to switch

the display on and off (does
not affect the function of the
equipment )

7

REMKO ML

Button functions

A symbol is shown on the display to indicate that the settings are being transferred.

Remote control ready for operation

RESET Button

A flashing dot on the remote control indicates that the remote control is
ready for operation.

Pressing the RESET button in the battery compartment resets the remote
control. The current time then has to be reprogrammed (see "CLOCK
button“).

RESET 5 sec. Setting the clock

CLOCK Button

ON/OFF Button

Press the CLOCK button in the battery compartment to set the time.
"CLOCK" will flash on the display. The HR. and MIN. buttons are used
to set the current time. Press the CLOCK button again to complete the
programming procedure,
the display will stop flashing.

CLOCKHR/MINCLOCK

Press the ON / OFF button to activate or deactivate the air conditioning
unit. The programmed settings and parameters are shown on the display
before the unit switches off.

ON/OFF ON/OFF

8

▲/▼ Buttons

The▼ button is used to reduce the target temperature, the ▲ button
increases it. In automatic mode the temperature can be increased
or decreased by 1°C. Temperature adjustment is not possible in
dehumidifying mode.

MODE Button

Cooling mode

▼

▼

Automatic mode

▲

▲

The display extinguishes
after 1 min.

Press the MODE button to switch between the operating modes. A total
of 4 modes are available:

1. Automatic cooling or heating mode

2. Cooling Mainly used in summer

3. Dehumidify Used in summer or winter

4. Heating Mainly used in winter

Automatic Cooling Dehumidify Heating

MODEMODEMODE

AUTOMATIC Mode

COOLING Mode

In automatic mode, the controller automatically selects heating or cooling
mode after it is switched on. The control range is 22 °C to 26 °C. This
can be raised or lowered using the ▲/▼ buttons.

MODE

Automatic

In cooling mode the room air is cooled to the preset target temperature.
The desired room temperature is set in 1 °C steps using the ▲/▼
buttons. If the room temperature reaches 0.5 °C above the set target
temperature, the indoor unit starts to cool the room air. If the actual
temperature falls approx. 1 °C below the set room temperature, the
controller switches the cooling off. In order to protect the compressor, the
controller will only switch the cooling back on after a holding period of 3
minutes.

MODE

COOLING
MODE

9

REMKO ML

DEHUMIDIFY Mode

HEATING Mode

In dehumidifying mode, the room temperature is reduced to 24°C. The
low refrigerant temperature causes the air temperature at the finned heat
exchanger to fall below the dew point. Any excess humdity in the air
condenses in the vaporiser. As a result the room is dehumidified. The fan
speed should be set to automatic to achieve maximum dehumidification.
In automatic mode, the fan is intermittently switched on and off.

MODE

DEHUMIDIFICATION
MODE

One can also use heating mode to heat the room in spring or autumn.
The room temperature is set in 1 °C steps using the ▲/▼ buttons.If the
room temperature falls 1 °C below the set target temperature, the indoor
unit starts to heat the room air.If the actual temperature exceeds the set
room temperature by approx. 1 °C, the controller switches the heating
off.In order to protect the compressor, the controller will only switch the
heating back on after a holding period of 3 minutes.

MODE

HEATING MODE

FAN Button

FIN Button

SWING Button

Press this button to set the fan speed. One can choose between low,
medium, high and automatic fan speed.

FANFANFAN FAN

Press this button to individually adjust the air outlet fins.
One can choose between 5 fixed positions and an oscillating function.

Press this button to select the oscillating function for the air outlet
fins. This allows direct switching from a fixed position to the oscillating
function. The swing function improves air circulation in the room.

10

SWINGSWINGSWING

SLEEP Buttons

Press these buttons to activate a program which will raise the target
temperature in cooling mode by 1 °C and 2 °C after 1 and 2 hours
respectively. In heating mode, the target temperature is lowered by 1 °C
and 2 °C after 1 and 2 hours respectively. The unit automatically switches
off after 8 hours.

SLEEPSLEEPSLEEP

TIMER Buttons

TIMER Button ON

TIMER Button OFF

These buttons are used to program the switch-on and switch-off times.
Pressing the Timer On and Timer Off buttons activates the timer and
extinguishes the clock on the display. The timer symbol for the switch­on/off time will flash. The Timer symbol on the indoor unit is lit. Press
the HR. and MIN. buttons to set the desired switch-on/off time. If set
successfully, the Timer symbol will flash a further 30 seconds. The unit
automatically switches on or off once the programmed time is reached.
If the indoor unit is switched on automatically, the previously set mode,
temperature and fan speed are activated. The switch-on/off time can be
prematurely cancelled by pressing the appropriate Timer button or ON/
OFF button. The timer symbol on the indoor unit extinguishes.

Timer On HR/MIN 30 sec.

TIMER Button ON/OFF

Timer Off HR/MIN 30 sec.

The controller switches the unit on and off at the programmed times.
During operation, all the settings and the timer symbol are shown on the
display. If the unit is not running, the display indicates 0->1 and the timer
symbol is shown.

Example:

Unit On Unit Off

The controller switches on at 10:20.
The unit remains operational until 5:00.

11

REMKO ML

Manual air distribution

The air outlet side includes
individually adjustable fins
to control the horizontal air
distribution.

CAUTION

Interior moving parts, e.g.
fans, are potentially hazardous
during operation!
Only adjust when swing mode
is switched off .

Shutdown

Temporary shutdown

1. Let the indoor unit run for 2 to
3 hours in circulation mode, or
in cooling mode at maximum
temperature, to extract any
residual humidity from the unit.

2. Shut down the unit using the
remote control.

3. Switch off the voltage supply to
the unit.

Manual air distribution

Adjustment lever, left

Permanent shutdown

Ensure that equipment and
components are disposed of in
accordance with local regulations,
e.g. through authorised disposal
and recycling specialists or at
collection points.

REMKO GmbH & Co. KG or their
authorised partners will be pleased
to provide details of specialists in
your area.

Adjustment lever, right

Care and maintenance

Regular care and maintenance
ensure trouble-free operation and
a long service life.

CAUTION

Prior to performing any
work, ensure the equipment
is isolated from the voltage
supply and secured to prevent
accidental switch-on!

Care

4. Preferably cover the unit with
plastic film to protect it against
the weather.

12

■

Ensure the indoor unit and
outdoor component are
protected against dirt, mould
and other deposits.

■

Clean the equipment using a
damp cloth. Do not use any
caustic, abrasive or solvent­based cleaning products. Do
not use a jet of water.

■

Clean the fins on the indoor
unit and outdoor component
prior to long shutdown periods.

Maintenance

■

It is recommended that you
take out a maintenance
contract with an annual service
from an appropriate specialist
firm.

TIP

This ensures the operational
reliability of your equipment!

Cleaning the housing of the
indoor unit

1. Disconnect the supply voltage
to the equipment.

2. Open and lift the front air inlet
guard.

3. Clean the guard using a soft,
damp cloth.

4. Switch the supply voltage back
on.

Air filter for indoor unit

Type of task

Checks/Maintenance/Inspection

General

Measure voltage and current

Check compressor/fans are functioning correctly

Check fan is functioning correctly

Dirt on liquefier/vaporiser

Check refrigerant fill quantity

Check condensation drain

Test insulation

Check moving parts

5. Any dirt can be cleaned off
using lukewarm water and mild
cleaning agents. The dirty side
should be face down (Fig. 3).

6. If water is used, let the filter
dry out properly in air before
replacing it in the unit.

7. Carefully insert the filter. Ensure
it locates correctly.

Commissioning

Monthly

Six-monthly

• •

• •

• •

• •

• •

• •

• •

• •

• •

2 Clean with a vacuum cleaner

3

Cleaning with lukewarm water

Yearly

Clean the air filter at least every
2 weeks. Reduce this interval if the
air is especially dirty.

Cleaning the filter in the
indoor unit

1. Disconnect the supply voltage
to the equipment.

2. Open the front of the unit by
lifting the guard and latching it
in position (Fig. 1).

3. Lift the filter and pull it down
and out.

4. Clean the filter using a normal
vacuum cleaner. The dirty side
should be face up (Fig. 2).

8. Close the front of the unit
in the reverse order to that
described above.

9. Switch the supply voltage back
on.

10.

Switch the unit back on.

1 Lift the guard

Cleaning the condensation
pump (accessory)

The indoor unit may include a
built-in or separate condensation
pump for pumping the
condensation to a drain at a higher
level.
Observe the care and maintenance
instructions specified in the
separate manual.

13

REMKO ML

Troubleshooting and customer service

The equipment and components are manufactured using state-of-the-art production methods and tested several
times to verify their correct function. If malfunctions should occur, please check the functions as detailed in the
list below. Please inform your dealer if the unit is still not working correctly after all the functional checks have
been performed!

Malfunction

Fault possible cause Checks Remedial measures

The unit does not start or
switches itself off

The unit does not respond to
the remote control.

Power outage, undervoltage,
defective mains fuse / main circuit
breaker switched off

Damaged mains cable

Waiting time after switch-on too
short

Temperate outside operating
temperature range

Overvoltages caused by thunder
storms

Fault in external condensation
pump

Transmission distance too far /
receiver affected by interference

Defective remote control

Receiver&transmitter unit exposed
to excessive solar radiation

Electromagnetic fields are
interfering with transmission

Button in remote control jammed /
two buttons pressed at same time

Batteries in remote control are flat

Are all electrical installations
functioning correctly?

Are all electrical installations
functioning correctly?

Have approx. 5 minutes
elapsed since the restart?

Are the fans in the indoor unit
and outside component working
correctly?

Has there recently been lightning?

Did the pump shut down due to
a fault?

Does the indoor unit beep when
pressing a button?

Is the unit running in manual
mode?

Does it function correctly in the
shade?

Does it function when
switching off possible sources of
interference?

Does the “Send” symbol appear
on the display?

Have new batteries been inserted?
Is the display incomplete?

Check the voltage and if necessary
wait for it to come back on

Repair by specialist

Schedule longer waiting times

Take into account the temperature
range for the indoor unit and
outside component

Switch off the mains protection
and switch it back on /
have it checked by a specialist

Check and if necessary clean the
pump

Reduce the distance to less than 6
m or change position

Replace the remote control

Place the receiver&transmitter unit
in the shade

Signal is not transmitted
when interference sources are
operational

Release the button / only press
one button

Insert new batteries

The unit is running but only
provides reduced cooling or
heating performance

Condensation is leaking out of
the unit

Filter is unclean / air inlet / outlet
blocked by foreign items

Doors and windows open.
Heating/cooling output increases

Neither cooling nor heating mode
has been set

Fins on outdoor component
blocked by foreign items

Leaking refrigerant circuit

Drainage pipe on collection
container clogged / damaged

Faulty external condensation
pump or float

Condensation has not drained
away and has collected in the
condensation pipe

Condensation does not drain off

Have the filters been cleaned? Clean the filters

Have modifications been made to
the building?

Is the cooling/heating symbol
shown on the display?

Is the fan on the outdoor
component running ? Are the fins
unobstructed?

Are there signs of frost on the fins
of the indoor unit?

Can the condensation drain off
without any obstruction?

Is the condensation tray full and
the pump running?

Is there a steady fall on the
condensation pipe? Check there is
no blockage in the pipe.

Are the condensation pipes
unblocked and is there a steady fall?
Are the condensation pump and
float switch functioning correctly?

Close windows and doors / install
additional units

Correct the settings for the unit

Check the fan or winter controller,
reduce the air resistance

Repair by specialist

Clean the drainage pipe and
collection container

Call out a specialist to replace the
pump

The condensation pipe must have a
fall. If necessary, clean the pipe

The condensation pipe must have a
fall. If necessary, clean the pipe.
A faulty condensation pump and
float switch should be replaced.

14

Error indicated by flashing code

Display Cause Required action

E1 Faulty circulation sensor in indoor unit Contact specialist dealer

E2 Faulty frost protection sensor in indoor unit Contact specialist dealer

E4

E5

E6 Break in internal control cable jumper Check jumper connector

Cooling mode: No cooling output after 30 min.
Heating mode> No heating output after 30 min.

Cooling mode: Frost protection has tripped
Heating mode> Overheating protection has tripped

Contact specialist dealer

Contact specialist dealer

Installation instructions for qualified personnel

Important points prior to
installation

■

Transport the unit in its original
packaging as close as possible
to the installation location.
This avoids transportation
damage.

■

Check that the packaged
contents are complete and
inspect the unit for any visible
signs of transportation damage.
Notify any deficiencies to
the contractual partner and
forwarding agent.

■

Lift the unit by its corners
and not the refrigerant or
condensation connections.

■

Insulate the refrigerant pipes
(injection and suction pipe),
valves and connections to make
them tight against vapour
diffusion. If necessary, also
insulate the condensation pipe.

■

Select an installation location
which allows air to freely
flow through the inlet and
outlet. (see section "Minimum
clearances").

■

Do not install the unit
adjacent to any hotspots. Unit
performance will be impaired if
installed next to hotspots.

■

Only open the stop valves
for the refrigerant pipes after
installation has been fully
completed.

■

Use caps or adhesive tape to
seal off the
open refrigerant pipes and
prevent the ingress of humidity.
Never kink or push in the
refrigerant pipes.

■

Avoid unnecessary bending.
This minimises the pressure
loss in the refrigerant pipes and
ensures that the compressor
oil can flow back without
obstruction.

■

Special measures concerning
the oil return pipe must
be taken if the outdoor
components is mounted above
the indoor unit.
See section "Oil return
measures".

■

Add refrigerant if the basic
length of the refrigerant pipe
exceeds 5 metres. The amount
of additional refrigerant is
given in the chapter "Adding
refrigerant".

■

Only use the union nuts
supplied with the refrigerant
pipes. These should only
be removed shortly before
connecting the refrigerant
pipes.

■

Establish all electrical
connections is accordance with
the relevant DIN- and VDE
standards.

■

Ensure the electrical cables
are properly connected to the
terminals, otherwise there is a
risk of fire.

15

REMKO ML

Wall breakthroughs

■

The wall breakthrough must
have a diameter of min. 70 mm
and a fall of 10 mm from inside
to outside.

■

We recommend that the
inside of the hole is padded or
lined, e.g. using a PVC tube,
to prevent the pipes being
damaged.

■

After installation has been
completed, use a suitable
sealing compound to close
off the wall breakthrough
(responsibility of customer). Do
not use cement- or lime/based
materials!

Pipes and cables in wall breakthrough

Control cable

Selecting the installation
location

Indoor unit

The indoor unit is designed for
horizontal wall-mounting above
doors. It can also be fitted high up
on walls (min. 1.75 m above the
level of the floor).

Outdoor component

The outdoor component is
designed for horizontal free­standing use in outdoor areas. It
should be placed on level, flat and
firm ground. The unit should also
be secured to prevent toppling.
The outdoor unit can be installed
both inside and outside buildings.
In the case of outdoor installation,
please follow the instructions given
below to protect the unit against
the weather.

Wind

If the unit is being installed in
windy areas, ensure that the
warm outlet air discharges in the
main wind direction. If this is not
the case it may be necessary to
install a windbreak (provided by
the customer). Ensure that the
windbreak does not adversely
affect the air intake to the unit.

Windbreak

Wind

PVC tube

Suction pipe

Condensation pipe

Injection pipe

Installation material

The indoor unit is fastened using
4 screws and a wall bracket. The
screws should be provided by the
customer.

The outdoor component is
fastened to the wall or ground
using 4 screws and a wall or floor
bracket.

Rain

The unit should be at least 10 cm
off the ground when mounted on
the roof or ground. An optional
floor bracket is available as an
accessory.

Sun

The liquefier on the outdoor
component radiates heat. Exposure
to direct sunlight will further
increase the temperature of the
fins and reduce the heat output
of the finned heat exchanger.
The outdoor component should
therefore be installed as near
as possible to the north side of
the building. If necessary, take
measures to provide sufficient
shade (responsibility of customer).
One possible solution is to build a
small roof. These measures should
not affect the flow of warm outlet
air.

Snow

The unit should be wall-mounted
in areas of heavy snowfall.

Installation should be at least
20 cm above the expected level
of snow to prevent snow from
entering the outdoor component.
An optional wall bracket is
available as an accessory.

Minimum clearance to snow

Snow

20 cm

16

Installation inside buildings

■

Ensure there is adequate heat
dissipation when placing the
outdoor component in cellars,
attics, adjoining rooms or halls
(Fig 4).

■

Install an additional fan with
a rated flow comparative to
that of the outdoor component
being installed in the room.
This is used in conjunction with
ventilation ducts to compensate
any pressure losses (Fig 4).

■ Ensure a continuous and

unobstructed air flow from
outside, preferably using
sufficiently large air intakes placed
opposite each other (Fig 4).

4 Installation inside buildings

Warm air

Additional
fan

Light
well

Warm air

■

Comply with any regulations
and conditions affecting
the statics of the building.
If necessary, fit acoustic
installation.

Outdoor component

Fresh
cold air

Light

well

Minimum clearances

Observe the minimum clearances
to allow access for maintenance
and repair work and facilitate
optimum air distribution.

Minimum clearances

120

Air intake

120

1500

200

Air outlet

ML 261 AT ML 351 AT ML 521 AT ML 681 AT

A 150 mm

B 700 mm 900 mm

C 400 mm

D 150 mm

E 200 mm 400 mm 600 mm

Air intake

120

D

A

E

Air outlet

B

All values in mm

C

17

REMKO ML

Installation

Oil return measures

If the outdoor component is
installed at a higher level than
the indoor unit, suitable oil return
measures must be taken. Usually
an oil pump bend is installed
for every 2.5 metres of height
difference.

Oil return measures

Outdoor
component

Oil pump bend

in suction pipe

to outdoor

component one

every 2.5 metres of

rising pipe

Radius:
min. 50 mm

max. 15 m

Indoor unit

NOTE

Installation should only be
performed by authorised
specialists.

Installing the unit

The indoor unit is fastened by
means of wall bracket. Take into
account the air outlet underneath
the unit.

1. Use the wall bracket dimensions
to mark the fixing points on
structural parts approved to
support the static load.

2. If necessary, remove the break­outs on the housing.

3. Connect the refrigerant
pipes, electrical cables and
condensation pipe to the indoor
unit as described below.

Connecting the refrigerant
pipes

The connections to the refrigerant
pipes are made at the rear of the
unit (responsibility of customer).

It may be necessary to fit a reducer
or flared adapter to the indoor
unit. These fittings are included
as standard. Once installed, the
connections should be made tight
against vapour diffusion.

CAUTION

The units are factory filled with
dry nitrogen to
check for leaks.
The pressurised nitrogen is
released when
loosening the union nuts.

Connection options for
indoor unit

Connection options

1

2

3

1 Exit on wall, right
2 Exit through wall, right
3 Exit through wall, left
4 Exit on wall, left

4

Wall bracket
for indoor unit

Attach the wall bracket for the
unit using suitable screws and wall
plugs.

4. Tilt back the indoor unit and
hang it into the wall bracket.
Press the underside of the unit
into the bracket (Fig 5).

5. Check that the unit is level.

5

Hooking in

The procedures for installing the
refrigerant circuit and mounting
the indoor unit and outdoor
component are described below.

1.

The required pipe diameters are

given in the table "Technical
data".

2. Remove the factory-fitted
protective caps and union
nuts on the connections.
These should be used during
installation.

3. Before flanging the refrigerant
pipes, ensure that the union nut
is fitted on the pipe.

4. Prepare the laid refrigerant
pipes as shown below

(page 19, figs 6+7).

18

5. Verify that the shape of the
flange is correct(Fig 8).

6. First connect and hand-tighten
the refrigerant connections
to ensure they are correctly
seated.

7. Now fully tighten the fittings
using 2 suitably sized open­ended spanners. Use one
spanner to counter the force
when tightening the fitting
(Fig 9).

8. Use insulation hoses which are
designed for this temperature
range and diffusion tight.

9. Lay the refrigerant pipes from
the indoor unit to the outdoor
component. Ensure that the

fastenings are adequate and if

necessary, take appropriate oil
return measures!

10.

Observe the permitted bending
radius for the refrigerant pipes
during installation. Never bend
a pipe twice in the same place.
Brittle pipes and potential
cracking are the consequences.

NOTE

Only employ tools and
components suitable for
refrigeration applications.

11.

Use the wall or floor brackets
to fit the outdoor component
against structural parts
approved to support the static
load (refer to the installation
instructions for the brackets).

12.

Ensure that structure-borne
sound is not transferred to parts
of the building . Use vibration
dampers to reduce the effects
of structure-borne sound!

13.

Prepare the refrigerant pipe
for the outdoor component as
described above.

Supplementary
installation notes

■

If the basic length of the
refrigerant pipe exceeds
5 m, add refrigerant when
commissioning the system
for the first time. (See section
"Adding refrigerant").

6 Deburring the refrigerant pipe

Refrigerant pipe

Deburrer

8 Correct flange shape

7 Flanging the refrigerant pipe

Flanging tool

9 Tightening the fitting

Tighten with 1st open­ended spanner

Tightening
torque:

1

4

15-20 Nm

“

3

8

33-40 Nm

“

1

2

50-60 Nm
Counter
using 2nd open­ended spanner

“

5

8

65-75 Nm

“

3

4

95-105 Nm

“

19

REMKO ML

Tightness check

Once all the connections have
been established, the pressure
gauge station is attached as
follows to the Schrader valve (if
fitted):
red = small valve
= injection pressure
blue = large valve
= suction pressure

Once connected, perform a
tightness test using dried nitrogen.

The tightness test involves
spraying a leak detection spray
onto the connections. If bubbles
are visible, the connections have
not been properly made. Re­tighten the connection or prepare
a new flange.

If the tightness test is successfully
completed, depressurise the
refrigerant pipes and start a
vacuum pump with an absolute
final partial pressure of min. 10
mbar to remove the air in the pipe.
Any humdity present in the pipes is
also removed.

CAUTION

A vacuum of min. 20 mbar
abs. must be created!

The time required to generate
the vacuum is dependent on
the pipework volume of the
indoor unit and the length of the
refrigerant pipes. This always takes
at least 60 minutes.
Once any foreign gases and
humdity have been completely
extracted from the system, the
valves on the pressure gauge
station are closed and the valves
on the outdoor component are
opened as described in the chapter
on "Commissioning".

Condensation connection

If the temperature falls below the
dew point, condensation will form
on either the vaporiser in cooling
mode or the liquefier in heating
mode.

The collection tray below the
vaporiser should be connected to
the drain.
The lower panelling on the
outdoor component acts as a
collection tray. Use the supplied
condensation connection for this
purpose.

■

The condensation pipe should
have a fall of min. 2 % (Fig

10). This is the responsibility
of the customer. If necessary,
fit vapour diffusion tight
insulation.

■

The condensation pipe from
the unit should run freely
into the drainage pipe. If the
condensation runs directly
into a sewer pipe, fit a trap to
prevent any unpleasant odours.

■

When operating the unit at
outdoor temperatures below
0 °C, ensure the condensation
pipe is laid to protect it against
frost. The lower panelling
on the housing should also
be protected against frost to
ensure condensation can drain
off at all times (responsibility of
customer).
If necessary, fit supplementary
pipe heating.

■

Once the pipe has been laid,
check the condensation drains
off and permanently seal it.

10

Fall on condensation pipe

at least
2% fall

The standard condensation hose is
for connection to the left side (as
viewed from the front).

Electrical connection

A protected mains supply and
control cable should be connected
to the outdoor component and
indoor unit respectively.

CAUTION

All electrical installation
work should be performed by
specialist contractors. Isolate the
voltage supply when connecting
the electrical terminals.

■

We recommend that customers
install a main/repair switch
in the vicinity of the outdoor
component.

■

If an optional condensation
pump is used in conjunction
with the unit, it may be
necessary to install an
additional relay with a higher
contact rating after the switch­off contact on the pump to
switch off the compressor.

■

Control cables should be
screened if laid in areas exposed
to strong magnetic fields..

■

Details concerning the electrical
protection of the system are
given in the section on technical
data.

20

Connecting the indoor unit

Make the connection as follows:

1. Open the air intake guard.

2. Unfasten the cover on the right
side and at the bottom right
rear (Fig 11).

3. Connect the unit to the
control cable from the outdoor
component (to be provided
by customer). See electrical
connection diagramOn the
ML 681 IT series, the terminal
block for the mains supply
and control contacts is located
behind the front cover.

4. Re-assemble the unit.

11

Connecting the indoor unit

Connecting the outdoor
component

Proceed as follows to connect the
cable:

1. Remove the cover from the
unit.

2. Remove the side panel next to
the terminals.

3. Select the cable cross-section
according to the relevant
standards.

4. Feed both cables through the
edge protection rings on the
fixed connection panel.

5. Terminate the cables as shown
on the electrical connection
diagram.

6. Support the cable in the strain
relief and re-assemble the unit.
(Fig 12).

CAUTION

Check all plugged and clamped
terminals to verify they are
seated correctly and making a
permanent contact. Re-tighten
as required.

12

Connecting the outdoor unit

Cover rear terminal block

front terminal block
control cable
from outdoor unit

supply voltage

from outdoor unit

Cover

Electrical connection diagram

Connections ML 261 to ML 521

Control
conductor
Control

conductor

Control
conductor

Outdoor
component

Phase conductor

Neutral conductor

PE

Earth conductor

3

Compressor contator

2

Reverse flow valve

11

Fan motor

Indoor unit Mains cable

Phase

L L L

conductor

rear

terminal

block

front

terminal

block

N

Neutral conductor

PE

3

2

PE

NN

230 V~,
50 Hz,
L1 / N
/ PE

Connection ML 681

terminal

Indoor unit Mains cable

Outdoor
component

L

Phase conductor

N

Neutral conductor

3

Compressor contator

2

Reverse flow valve

1

Fan motor

Earth conductor

PE

front

block

L

N

3

2

1

PE

Control

conductor

Control

conductor

Control

conductor

L1

N

230 V~,
50 Hz,
L1 / N
/ PE

PE

21

REMKO ML

Electrical circuit diagram

ML 261 IT to ML 681 IT

Fan motor

Reverse flow valve

Compressor

Compressor

Liquefier fan

Reverse flow valve

L
N

3
1
2

AC-N

Transfor

mer

Vaporiser fan motor

FM

AC-L
COMP

Vaporiser sensor

Swing motor

SM

Air circulation sensor

Display

Receiver

board

ML 261 AT to ML 681 AT

Control
cable

Mains
cable

Colour code

WH = white
BU = blue
BR = brown
BK = black

1

2

3

N

L

Reverse flow valve

BK

BU

BN

BU

WH

Compressor contator

Liquefier fan

BK

S

Compressor

C

BU

R

22

Before
commissioning

After the tightness check has
been successfully completed,
connect the vacuum pump via
the pressure gauge station to
the valve connections on the
outdoor component (see chapter
"Tightness check") and create a
vacuum.

Perform the following checks
prior to commissioning the
unit for the first time and after
any interventions affecting the
refrigerant circuit. Record the
results in the commissioning
report:

■

Check all refrigerant pipes and
valves using leak detection
spray or soapy water to ensure
they are tight and that the
suction and injection pipes
are not accidentally mixed up.
Perform this check when the
unit is not running .

■

Check the refrigerant pipes and
insulation for signs of damage.

■

Check the electrical connections
between the indoor unit and
outdoor component to verify
the correct polarity.

■

Check that all fastenings,
mountings etc. are firm and at
the correct level.

Add refrigerant

CAUTION

Wear protective clothing when
handling refrigerant.

The equipment contains a basic
quantity of refrigerant. Extra
refrigerant must be added if the
basic length of the refrigerant
pipes exceeds 5 metres. Refer to
the following table:

ML

ML

ML

521

25

g/m

ML

681

45

g/m

Basic pipe
length
Up to and
incl.
5 m
5 m to max.

25 m

261

351

Additional fill quantity

0 g/m

25

25

g/m

g/m

Commissioning

NOTE

Commissioning should only be
performed and documented
by specially trained personnel.

The system can be commissioned
once all the components have
been connected and tested.
A functional check should be
performed to verify its correct
function and identify any unusual
operational behaviour prior to
handing it over to the operator.

Functional checks and
test run

Check the following points:

■

Tightness of the refrigerant
pipes.

■

Compressor and fan running
smoothly.

■

In cooling mode, cold air should
be output by the indoor unit,
and warm air should be output
by the outdoor component.

■

Functional test of the indoor
unit and all program sequences.

■

Check the surface temperature
of the suction pipe and
determine the overheating
of the vaporiser. Measure
the temperature by holding
a thermometer against the
suction pipe and subtracting
the boiling point temperature
indicated on the pressure
gauge.

■

Record the measured
temperatures in the
commissioning report.

Functional test for cooling
and heating modes

1. Remove the protective caps on
the valves.

CAUTION

Note that the employed
refrigerant is always filled in
liquid form!

NOTE

Check the overheating to
determine the refrigerant fill
quantity

NOTE

Check that the stop valves
and valve caps are tight after
carrying out any work on the
refrigerant circuit. If necessary,
use appropriate sealant
products.

2. Start the commissioning
procedure by briefly opening
the stop valves on the outdoor
component until the pressure
gauge indicates a pressure of
approx. 2 bar.

3. Use leak detection spray or
suitable devices to check that all
the connections are tight.

23

REMKO ML

4. If no leaks are found, fully
open the stop valves by turning
them anti-clockwise using a
spanner. If leaks are found,
repair the faulty connection. It
is imperative that the vacuum
creation and drying steps are
repeated!

5. Switch off the main circuit
breaker or remove the fuse
(provided by the customer).

6. Use the remote control to
switch on the unit and select
the cooling mode, maximum
fan speed and lowest target
temperature.

7. Measure and record all
the required values in the
commissioning report and
check the safety functions.

8. Check the control system in the
unit by referring to the

Functions. Timer, temperature

setting, fan speeds and
switching to ventilation or
dehumidifying mode.

9. Check the correct function
of the condensation pipe by
pouring distilled water into the
condensation tray.
A bottle with a spout is
recommended for pouring the
water into the condensation
tray.

10.

Switch the indoor unit to
cooling mode.

11.

Check the correct function
and settings of all regulation,
control and safety devices
during the test run.

12.

Check the control system in the
indoor unit using the functions
described in the manual.
Timer, temperature settings and
all mode settings in the chapter
"Operation".

13.

Check the overheating,
outdoor, indoor, outlet and
vaporisation temperatures and
record the measured values in
the commissioning report.

14.

Switch the indoor unit to
heating mode.

15.

Check all the previously
described safety devices and
functions during the test run.

16.

Record the measured values in
the commissioning report.

17.

Remove the pressure gauge.
Check that seals have been
fitted in the sealing caps.

Final tasks

■

Re-fit all the dismantled parts.

■

Instruct the operator on how to
use the equipment.

Unit dimensions

ML 260 AT to ML 520 AT

780

ML 680 AT / ML 680 IT

845

We reserve the right to modify the dimensions and constructional design as part of the ongoing technical development process.

24

250

285

540

615

280

510

500

ML 260 IT / ML 350 IT

790

ML 520 IT

930

ML 680 IT

315

1035

275

200

275

200

320

220

All values in mm

Exploded view of ML 261 IT to ML 681 IT

11

10

12

7

8

5

2

We reserve the right to modify the dimensions and constructional

design as part of the ongoing technical development process.

9

1

6

4

3

Spare parts list

No. Designation ML 261 IT ML 351 IT ML 521 IT ML 681 IT

1 Front panel, complete 1109400 1109413 1109426 1109439

2 Air filter, set 1109401 1109414 1109427 1109440

3 Circuit board, display 1109402 1109415 1109428 1109441

4 Swing motor 1109403 1109416 1109429 1109442

5 Outlet fins, set 1109404 1109417 1109430 1109443

6 Condensation tray 1109405 1109418 1109431 1109444

7 Vaporiser 1109406 1109419 1109432 1109445

8 Fan wheel 1109407 1109420 1109433 1109446

9 Fan motor 1109408 1109421 1109434 1109447

10 Control board 1109409 1109422 1109435 1109448

11 Transformer 1109410 1109423 1109436 1109449

12 IR remote control 1109411 1109424 1109437 1109450

Spare parts (not illustrated)

Circulation sensor / vaporiser sensor 1109412 1109425 1109438 1109451

When ordering spare parts, please state the computerised part no., unit number and type (see identification plate)!

25

REMKO ML

Exploded view ML 261 AT to ML 681 AT

8

9

4

3

2

13

7

12

5

1

6

10

11

Spare parts list

No. Designation ML 261 AT

1 Front panel 1107800 1107813 1107826 1107838
2 Fan blade, liquefier 1107801 1107814 1107827 1107839
3 Fan motor, liquefier 1107802 1107815 1107828 1107840
4 Ribbed liquefier 1107803 1107816 1107829 1107841
5 Cover panel 1107804 1107817 - ­6 Side panel, right 1107805 1107818 - ­7 Compressor, complete 1107806 1107819 1107830 1107842
8 Condenser, compressor 1107807 1107820 1107831 1107843
9

Condenser, liquefier fan
10 Stop valve, suction pipe 1107809 1107822 1107833 1107845
11 Stop valve, injection pipe 1107810 1107823 1107834 1107846
12 Compressor contator 1107811 1107824 1107835 1107847
13 Reverse flow valve 1107812 1107825 1107836 1107848

Spare parts (not illustrated)

Rear panel with side section - - 1107837 1107849

When ordering spare parts, please state the computerised part no., unit number and type (see identification plate) !

26

1107808 1107821 1107832 1107844

ML 351 AT

ML 521 AT

ML 681 AT

Technical data

Series ML 261 ML 351 ML 521 ML 681

Operating mode Wall-mounted air-conditioning units for combined cooling/heating

Nominal cooling output

Nominal heating output

Energy efficiency class, cooling

Energy efficiency ratio EER

Energy efficiency class, heating

Coefficient of performance COP

Operating range (room volume), approx. m³ 80 110 160 230

Refrigerant R 410A

Voltage supply V/Hz 230 / 1~ / 50

Nom. electrical power consumption, cooling

Nom. electrical power consumption, heating

Nom. current consumption, cooling

Nom. current consumption, heating

Electr. starting current, max. A 21 28 35 51

Refrigerant connection, injection pipe Inches(mm) 1/4 (6.35) 1/4 (6.35) 1/4 (6.35) 3/8 (9.52)

Refrigerant connection, suction pipe Inches(mm) 3/8 (9.52) 1/2 (12.70) 1/2 (12.70) 5/8 (15.90)

Max. operating pressure kPa 4200 / 4200

Data specific to indoor unit

Adjustment range, room temperature °C +16 to +31

Working range °C +15 to +31

Air flow rate per stage m³/h 320/370/420 380/450/520 600/700/800 800/900/1000

Noise output per stage

Protection degree IP X0

Condensation connection mm 17 17 17 17

Dimensions Height

Width mm 790 790 930 1035

Depth mm 200 200 200 220

Weight kg 8.0 10.0 12.0 16.0

Data specific to outdoor unit

Working range, cooling °C +7 to +48

Working range, heating °C -7 to +25

Air flow rate, max. m³/h 1925 2050 2050 2310

Protection degree IP 24

Noise level, max.

Refrigerant, basic quantity kg 0.70 1.00 1.45 1.80

Refrigerant, additional quantity> 5 m g/m 25 25 25 45

Refrigerant pipe, max. length m 25 25 25 25

Kältemittelleitung, Höhe max. m 15 15 15 15

Dimensions Height mm 540 540 540 615

Width mm 780 780 780 845

Depth mm 250 250 250 285

Weight kg 30.0 34.0 40.0 48.0

Serial number 803... 804... 805... 806...

Computerised part no. 1630260 1630350 1630520 1630680

1) Air inlet temperature TK 27°C / FK 19°C, outdoor temperature TK 35 °C, FK 24 °C, max. air flow rate

2) Air inlet temperature TK 20°C, outdoor temperature TK 7°C / FK 6°C, max. air flow rate

3) Distance 1 m free air

1)

2)

1)

1)

2)

2)

1)

2)

kW 2.69 3.59 5.27 6.84

kW 2.96 4.24 6.31 7.72

A A B B

3.32 3.23 3.12 3.05

A A C C

3.70 3.66 3.29 3.24

1)

kW 0.81 1.11 1.69 2.24

2)

kW 0.80 1.16 1.92 2.38

A 3.60 4.99 7.76 10.43

A 3.61 5.32 8.87 10.75

ML 261 IT ML 351 IT ML 521 IT ML 681 IT

3)

dB(A) 30/34/38 32/36/40 35/39/43 37/41/45

mm 275 275 275 320

ML 261 AT ML 351 AT ML 521 AT ML 681 AT

3)

dB(A) 52 53 55 56

27

REMKO INTERNATIONAL

… and in your area!
Profit from our experience and advice

REMKO GmbH & Co. KG

Klima- und Wärmetechnik

Im Seelenkamp 12 · 32791 Lage

Postfach 1827 · 32777 Lage

Telephone [phone]

Telefax [phone]

E-mail [e-mail]

Internet www.remko.de

Hotline

Advice, sales air conditioning technology
[phone]

Advice, sales heating technology
[phone]

Spare parts sales
[phone]

Export
[phone]

Consultancy

Intensive training means

our consultants are always

up-to-date with the latest

developemnts. This has given

us the reputation of being more

than just a good and reliable

supplier:

REMKO, a partner who helps

solve problems.

.

Sales

REMKO not only has a well-

established sales network

at home and abroad, it also

employs highly trained sales

specialists.

REMKOOur field staff are more

than just salesmen: above all,

they must advise our clients in

the areas of air conditioning and

heating technology.

Customer service

Our equipment is precise and

reliable. However, should a fault

should occur REMKO customer

service is quickly at your side.

Our comprehensive network of

experienced dealers guarantees

quick and reliable service.

Service
[phone]

Subject to technical modifications, no responsibility taken for the correctness of information!