Lennox FAC 120, FAC 150, FAC 170, FAC 200, FAC 230 Application Manual

APPLICATION
GUIDE

FAC - FAG - FAH - FAM

Air cooled rooftop packaged unit

FLEXAIR

85  230 kW

FLEXAIR-AGU-1505-E

lennoxemeia.com

TABLE OF CONTENTS

FLEXAIR

APPLICATION GUIDE

GENERAL DESCRIPTION

1. 4

OPTIONS DESCRIPTION

2. 14

GENERAL DATA

3. 22

OPTIONS DATA

4. 26

Ref : FLEXAIR-AGU-1505-E

STANDARD UNIT PERFORMANCES

5. 276

FAN PERFORMANCES

6. 42

HEAT RECOVERY SOLUTIONS PERFORMANCES

7. 45

HEATING AUXILIARIES PERFORMANCES

8. 47

ACOUSTIC DATA

9. 52

ELECTRICAL DATA

10. 54

DIMENSIONAL DATA

11.

OPTIONS WEIGHTS AND ACCESSORIES PRESSURE DROPS

12.

56

75

Product designed and manufactured under quality management

systems certifi ed ISO 9001 and ISO 14001.

All the technical and technological information contained in this manual, including any drawing and technical descriptions provided
by us, remain the property of Lennox and must not be utilised (except in operation of this product), reproduced, issued to or made
available to third parties without the prior written agreement of Lennox.

Application Guide /FLEXAIR-AGU-1505-E

www.eurovent-certifi cation.com

www.certifl ash.com

Our company’s products comply

with European standards.

• 1 •

• 2 •

Application Guide / FLEXAIR-AGU-1505-E

MODEL NUMBER DESCRIPTION

EXAMPLE :

F A C 300 D N M 1 M

FLEXAIR

F

Air cooled

A

Water cooled

W

No condenser

N

M

H

Revision number

R410A

HFO

400V/3/50

M

230V/1/50

T

Cooling

C

Heat pump

H

gas fi red

G

dual fuel

M

heat recovery

X

Cooling capacity in kW

S

D

T

F

High heat

H

Standard heat

S

No heat

N

1 Circuit

2 Circuits

3 Circuits

4 Circuits

No refrigerant

N

Application Guide /FLEXAIR-AGU-1505-E

• 3 •

1- GENERAL DESCRIPTION

SUSTAINABLE ENERGY
DEVELOPMENT CHALLENGES

Faced with challenges relating to competitiveness and climate
change, Europe has launched several initiatives for an intelligent
energy strategy.

New regulations refl ect the European Union’s commitments on
climate change and its determination to reach 20% effi ciency
improvement in buildings by 2020.

EPBD

ENERGY PERFORMANCE OF
BUILDING DIRECTIVE

One of the major requirements of the new EPBD is to set Energy
Certifi cates for buildings which grade the energy effi ciency based
on the building annual energy consumption. Soon companies
will have to display their energy certifi cates to the public.

THE EXPERIENCE & COMMITMENT OF
THE EUROPEAN LEADER TO DRIVE
CONTINUOUS ENERGY SAVINGS

LENNOX : THE BEST LIFE CYCLE
COST IN THE MARKET

FLEXAIR provides the best life cycle cost thanks to

high energy effi ciency and reduced set up time and
maintenance costs.

Low Energy consumption

• For a packaged air conditioner, 90% of the CO2
emissions are indirect emissions caused by the
energy consumption.

• 35% energy savings with FLEXAIR when com­pared to a standard rooftop installed on a retail
building.

• Innovative solutions for long lasting energy savings:

. eDrive Direct transmission variable speed ventilation system

. Advanced refrigeration system with multiscroll R410A com-

pressor assemblies, electronic expansion valves, extended
heat exchange surface area, alternate and dynamic defrost
cycles.

. Fresh air and free cooling management.

. Optimized operation with eClimatic

Lennox contribution to combat rising energy costs and global
warming is to design innovative, effi cient and dependable
products, while providing best comfort and air quality.

As a major player in the European
HVAC market, Lennox is a reference
in sustainable development and has
been assembling its products in ISO­14001 certifi ed factories since 2007.

eComfort illustrates Lennox
commitment towards energy
efficiency and environmentally

™

eComfort

efficiency s environment

friendly solutions.

Like any other Lennox Rooftop
unit,

FLEXAIR is Eurovent

certifi ed.

Reduced maintenance Costs

• Fully factory tested plug and play packaged system.

• eDRIVE direct transmission plug-fan with zero maintenance
and airfl ow measurement with eFlow.

• eClimatic, eClimatic
supervision through GPRS with ADALINK Service.

Wizard, unit remote management and

Better recycling management

• Unit assembled in an ISO14001 certifi ed facility.

• Refrigerant R410A to reduce refrigerant charge.

• Reduced material usage with compact pac­kaged design.

• 4 •

Application Guide / FLEXAIR-AGU-1505-E

1- GENERAL DESCRIPTION

1.1. GENERAL FEATURES

FLEXAIR range constitutes a packaged solution, easy to deliver
and quick to install on the roof.

Operating range shall be between 46°C and minus 12°C with
4 versions : cooling, heating, cooling with gas burner or dual
heat (heating with gas burner). All units are factory assembled,
internally wired, fully charged with refrigerant, and 100% run­tested before leaving the factory.

EC FANS TECHNOLOGY

FLEXAIR units are fi tted with EC fans as standard, the variable

speed option will save energy and reduce maintenance costs.

HIGH INDOOR AIR QUALITY

Filtration
FLEXAIR offers different fi ltration levels, ensuring the minimum

pressure drop.
The unit is fi tted with EU3 fi lters as standard, but it can be
confi gured with :

- G4 fi lters

- G4+F7 fi lter option / effi ciency > 85% / 0,4 μm particles

Free cooling

Some times the thermodynamic cooling can be replaced by
free cooling by introducing cold outside air into the building.
FLEXAIR saves energy with automatic calibration of fresh air :

- Intelligent Fresh Air Management (patent 03 50616)

- Motorised fresh air damper with enthalpy control (option)

- CO2 sensor to adjust the percentage of fresh air to the Indoor
Air Quality (option)

eClimatic ADVANCED CONTROLLER

eClimatic is the new generation controller that improves effi ciency
and helps set up and service operations to guarantees long
lasting performance

1.2. CASING

FLEXAIR indoor section is built with precoated galvanized steel
panels painted in RAL 9003 color, specially designed for corrosion
resistance and to ensure long operation life time.
Double skin can be demanded as an option.

Condensing section mounted in a rigid base frame to ensure
good support for compressors and giving rigidity to the complete
structure.

1.3. ADVANCED REFRIGERANT
CIRCUIT

FLEXAIR presents the most advanced design in the refrigerant
pipes, optimizing pipe length and at the same time giving the
best access for service and maintenance operations.
The exchangers have been specially designed by Lennox for
R410A operation, this copper tube and aluminum fi ns exchangers
have been tested to give the best heat transfer and the best
energy ratios.
The refrigeration circuit is responsible for up to 40% of the annual
energy consumption of a typical packaged air conditioning unit.

FLEXAIR features high effi ciency, environmentally friendly
refrigeration circuits with multiscroll R410A compressors,
electronic expansion valves and optimized heat exchange
surface area.

HEAT RECOVERY SOLUTIONS

FLEXAIR range includes a heat recovery wheel to recovery

energy from the extraction air
This heat recovery wheel is fi tted in a separated module to be
installed on site

Application Guide /FLEXAIR-AGU-1505-E

• 5 •

1- GENERAL DESCRIPTION

SAVING ENERGY WITH ADVANCED
REFRIGERATION CIRCUIT DESIGN

R410A refrigerant

Effi cient systems such as FLEXAIR are designed around R410A
refrigerant to achieve the best performances.

• Energy effi cient refrigerant thanks with pressure drop in the
pipes: Higher evaporating pressure and lower condensing
pressure improve compressor EER & COP.

• R410A compressors have a better isentropic effi ciency.

• Environmentally friendly refrigerant:

It contains No Chlorine (ODP =0). Signifi cant refrigerant charge

reduction (-40%) that limits the global warming potential of the
system. R410A optimized heat exchangers use less material
(copper, aluminum …)

1.4. MULTISCROLL COMPRESSOR
TECHNOLOGY

FLEXAIR units are provided with tandem compressors, to profi t
from the multiscroll compressor technology and giving the highest
seasonal performance and the best SEER coeffi cients.

High effi ciency multiscroll technology

Air conditioning equipments are sized to cover the need for the
most critical weather conditions which most likely will occur only
a few days or even a few hours during the year.

Most of the time, in Europe, the external temperature drops below
the reference value and consequently systems usually run 96%
of the time at part load. It is therefore important to design system
around part load performance to achieve the lowest possible
annual energy consumption.

FLEXAIR provides high effi ciency and best possible part load
effi ciencies year round with high effi ciency multiscroll R410A
compressor technology.

Evolution of the net EER with varying capacity load

Net EER

4,5

4,0

3,5

3,0

2,5

MultiScroll + eDrive

A

MultiScroll

Inverter Scroll

B
C

TM

Single Scroll

2,0

1,5

A Multiscroll + eDRIVE C Multiscroll

B Inverter scroll D Single scroll

Source: PERSAPAC Study by Cetiat, Eurovent, Armine & EDF
Lennox Europe Laboratory comparative testing on rooftops

D

10 20 30 40 50 60 70 80 90 100

Capacity load in % of nominal

• 6 •

Application Guide / FLEXAIR-AGU-1505-E

1- GENERAL DESCRIPTION

Multiscroll” compressor technology with electronic expansion
valves allows energy consumption reduction when compared
to “inverter” solutions:

• Multiscroll compressors are always running at their best
nominal operating conditions whereas compressors with
inverter control usually run at 90 Hz for nominal point down
to 30 Hz for low capacities.

• Energy consumption due to inverter electronics for speed
variation can reduce effi ciency by up to 5%.

• Multiscroll compressor assemblies optimize heat exchanger
usage during part load operation. For example, with 50%
capacity load, a FLEXAIR would only start one compressor
on each circuit. The running compressors would then benefi t
from the whole heat exchange surface area and the whole
airfl ow rate: The EER is then increased to 4.5 in some cases.

• Multiscroll compressor assemblies improve operating limits
giving the possibility to unload compressors providing cooling
to the building even when the outdoor temperatures are very
high. With unloading, FLEXAIR can operate and supply
cooling operating one compressor with outdoor temperatures
reaching 50°C.

1.5. ELECTRONIC EXPANSION
VALVES

The new electronic expansion valves are directly driven by the
eClimatic and optimize the performances in both cooling and
heating mode and provide reliable and accurate operation in all
conditions all year round.
This model of electronic expansion valves ensures also smooth
and precise control at low capacities for improved part load
performances.

Application Guide /FLEXAIR-AGU-1505-E

• 7 •

1- GENERAL DESCRIPTION

1.6- EC FANS IN SUPPLY AND EXTRACTION

EC fan technology offers the maximum effi ciency together with
the minimum power consumption. That’s why FLEXAIR provides
EC fans both in indoor and exhaust section.

FLEXAIR will adapt the fan pressure to the different conditions
of the unit, and will provide high pressure available in the duct
even when all the options have been selected.

The EC plug-fan technology allows:

- Adapting airfl ow at commissioning

- Varying airfl ow during unit operation providing progressive
infl ation of smooth /textile ductworks

- Easy maintenance operations, as there is not pulleys and
belts regulation

eClimatic profi ts about this EC technology by:

- Monitoring the airfl ow in the service terminal

- Compensating the airfl ow if the fi lters are dirty

- Regulating the airfl ow to arrive to the desired set point tem-
perature.

Optimize the air-fl ow to the load demand (reduce consumption
when possible)

2

3

Annual compressor consumption

1

Annual consumption of other electical systems

2

Remaining annual fan motor consumption

3

Energy savings thanks to eDRIVE

4

4

1

40 %

18 %

12 %

30 %

VARIABLE SPEED DRIVE

Airfl ow reduction during part load operation and dead zone can
help save on energy consumption.

Condensing section mounted in a rigid base frame to ensure
good support for compressors and giving rigidity to the complete
structure.

eDRIVE
VENTILATION

eDRIVE is a standard feature
of Lennox FLEXAIR units
for ventilation with direct
transmission, variable speed
drives that saves energy and
reduces maintenance costs.

SAVING ENERGY WITH eDRIVE VARIABLE
SPEED, DIRECT DRIVE FAN.

With a rooftop, the blower fan motor is one of the major contributors
to annual energy consumption. Fans usually run 97% of the year
at full speed to circulate the air inside the building. 42% of the
annual energy consumption of an air conditioner is due to the
fan motor, which can be more than compressors.

There is no need to reduce airfl ow rate too much to achieve
important energy savings: For example reducing airfl ow rate by
only 25% will save 60% on the fan motor energy usage.

Fan absorbed power with variable airfl ow rate

(% of nominal)

Fan absorbed power

Airfl ow rate

(% of nominal)

• FLEXAIR integrates the new eDRIVE which automatically
adjust airfl ow rate to the needs, saving up to 30% annual
rooftop energy consumption.

• Airfl ow Rate can be easily adjusted to the exact needs, thanks
to eFlow the airfl ow measurement and display system.

• eDRIVE will correct power factor to reduce current.

• eDRIVE integrates soft starter feature as standard, that will
reduce inrush current during fan starts and makes the unit
fully compatible with fl exible ducts air diffusion systems.

- 25%

• 8 •

Application Guide / FLEXAIR-AGU-1505-E

1- GENERAL DESCRIPTION

1.7- eCLIMATIC NEW CONTROL

Our FLEXAIR range includes our New e-climatic control
generation.The main features of this control are :

- Plastic cover to protect the circuit board from water entry
and humidity and with all the different connection terminals
correctly identifi ed.

- Two independent buses, one for display and sensors connec­tion and another one for internal components.

- Possibility of storing all parameterized conditions before an
alarm is produced.

- Stronger hardware thanks to the plastic cover which protects
the circuit board from water entry and humidity (and at the
same time clearly identify all the different connection termi­nals)

- More reliable hardware thanks to the different communi­cation buses for internal/main devices (compressors, fans,
etc.) and for the remote/accessory ones (display, probes),
which preserve the regular unit operation even in case of
commissioning miswirings

- Enhanced ClimaticTM regulation thanks to the better em­bedded processor and to the new Universal I/O chip, which
allows to match better contacts, probes and relays to the
controller board.

- Internal log memory to record unit operating trends (e.g.
temperatures before alarm occurrence).

OPTIMIZED OPERATION AND SETUP
SAVES ENERGY

Three different platforms are available :

● End customer display DC: with basic confi gurations, set
points, main temperature readings and alarms.

● Multiple display DM: graphic customer display with basic
confi guration of the end customer display plus schedule
programming and set of fresh air %.

● Service display DS: Specially focused to maint

4

6

5

2

7

3

1

eClimatic is designed to provide the best effi ciency throughout
unit’s lifecycle while ensuring reliable and consistent operation
with user-friendly interfaces .This controller monitories more
machine parameters than ever to improve energy effi ciency
and reliability

1 Indoor air temperature (humidity and CO2 levels as an option )

2 Outdoor air temperature (outdoor humidity as an option )

3 Return and supply air temperature

4 Filter pressure drop

5 Airfl ow rate with eFlow

Refrigeration circuit effi ciency management

Climatic control regulation
The Climatic controls the blowing air temperature to achieve the
customer comfort in the most effi cient way, matching perfetctly
the cooling/heating load with the optimum unit capacity staging
(multiscroll compressors, heat recovery modules, freecooling,
gas burners, water coils, etc.).
The unit reliability is ensured by a complete set of protections as
compressor envelop control, air-fl ow and pressure drops check,
advanced refrigerant leakage detection, compressor anti short
cycling rules.
All these fetaures are designed to optimize the unit performance,
but at the same time to increase its life-time and make easier
its maintenance.

Dynamic defrost:

It is a standard feature of all Lennox heat pumps. It limits the
number and the duration of the defrost cycles in winter to maximize
COP. With a smart and propietary frost-detection system, the
lennox rooftops autumatically optimize the number and the
durantion of the defrost cycles to get the best units perfonces
in every enviromental conditions.

6 Refrigerant pressures, temperatures & compressor monitoring

7 Power energy metering (option )

Application Guide /FLEXAIR-AGU-1505-E

• 9 •

1- GENERAL DESCRIPTION

Free cooling:

It is one of the most important features of this rooftop as it maximise
seasonal effi ciency by reducing the use of thermodynamic cooling
in mid season.

Intelligent fresh air management:

With accurate percentage of fresh air the dampers are regularly
calibrated to introduce just the required amount of fresh air in the
building to reduce annual energy consumption. The fresh air ratio
can also be controlled using the indoor CO2 level as an input.

Intelligent heating priority optimization:

This unique feature on the market, allows the user to program the
priority between the different heating elements (thermodynamic,
electric pre-heaters or auxiliary heating). This is particularly
interesting on dual fuel units or units with electrical pre-heaters.
This feature maximizes energy effi ciency by optimizing heat pump
operation depending on the outdoor temperature.

Full Scheduling

Impressive energy savings can be done with a proper time­scheduling that optimizes the unit operation to the different load
scenarios of each installation.
For that reason the Climatic offers a weekly-based calendar with
up to 7 time-bands per day and 4 pre-set modes (Unoccupied,
Day, Day 1, Day 2).
For each of this pre-set modes, plenty of unit settings can be
optimized to the different moments of the day, for example during
the unoccupancy periods the comforrt setpoints could be relaxed,
during the energy-cost peaks hours the hot water coils or gas
burners could be preferred to compressor or electrical heaters,
fresh-air introduction can be reduced to warm-up the building
before customer arrival, etc.

Morning anticipation and dynamic set point

The unit can be programmed to switch-on in the morning to reach
the occupied zone temperature set point just in time.
The rooftop will start heating the building at a different time in
the morning depending on the outdoor temperature: The lower
the outdoor temperature, the earlier the rooftop would start to
ensure that the set point is reached by the time the fi rst occupied
zone (Z1) is starting. This is to avoid early start when outdoor
temperature is mild.
Example for a unit programmed to anticipate morning switch-on
if outdoor temperature is below 10°C at a rate of 10 minutes/°C.

Start time

Z1 = 08h00

Actual switch-on

Z1 = 07h30

Actual temp.

Dynamic set point can be used in summer to offset the ambient
temperature set point according to the outdoor temperature.
This is to avoid large temperature difference between indoor and
outdoor. The indoor temperature set point would then increase
with the outdoor temperature improving comfort and saving large
amount of energy.

Gradient : 10 min / °C

7°C

10°C

10°C

1 2

Unoccupied mode Day mode

3 4

Day1 additionnal mode Day2 additionnal mode

Communication and unit interlink

Master/slave or cascade control is a standard feature of the
FLEXAIR units. It can be used to connect up to 24 rooftops.
The units can then be programmed to optimize effi ciency and
improve reliability following 6 different strategies

Multi rooftops regulation

In case of multi-rooftop installations, The Climatic control of each
unit can improve the unit synergies and optimize the total air­conditioning performance, without any additional cost or external
dedicated "Building Manager System", but just linking the units
together (up to 8) in the same network and appling any of the
following smart strategies::

1: Master Slave "total":

The master gives the ventilation order, its set point and its room
temperature/humidity/CO2 to all other rooftops.

2: Master Slave "temperature":

The master gives the ventilation order and its room temperature/
humidity/CO2 to all other rooftops, but they have their own set
point.

• 10 •

Application Guide / FLEXAIR-AGU-1505-E

1- GENERAL DESCRIPTION

3: Master Slave "average":

The master gives the ventilation order and the room temperature/
humidity/CO2 used by all rooftop is the average of all rooftop,
each rooftop has its own set point.

4: Master Slave "cooling/heating":

All rooftop are stand-alone but the slaves have to have the same
running mode as the master (Cooling or heating).

5: Master Slave “Back-up”:

One rooftop is the back-up unit and will operate if any of the
other rooftops is stopped due to a major problem.

6: Rolling Back-up mode:

Same as above, except the "back-up" unit will change once a
week on Tuesday.

Note that, the outside temperature/humidity/CO2 given to all
rooftops can either be the average of all unit connected or the
external humidity/temperature of the master, allowing the use
of a single "weather station" for the whole site.

Faults and alarms

eCLIMATIC manages more than 90 different faults and alarms
codes and can store the last 32 with time and date. The stored
faults and alarms can then be displayed on the DS service
display and on the communication bus with the full text detail.

1.8. CONSTRUCTION, INSTALLATION
AND SERVICE

UNIT CONSTRUCTION

FLEXAIR by Lennox is assembled with the highest standards

of quality.

FLEXAIR units comply with the PED 97-23 and EN 60204
standard. It is manufactured in ISO 9001 and ISO 14001 factories.

This construction guarantees high corrosion resistance and lower
the weight impact, also ensuring that the air leakages are reduced
to the minimum. To improve the resistance to anticorrosion, the
panels are prepainted in RAL 9003.

TRANSPORT AND HANDLING

To facilitate handling of the
unit and minimize the risk of
damage, FLEXAIR units are
provided with lifting lugs located
in the base frame of the unit.

For transport and handling,
the units are wrapped in a
retractable plastic protection

PLUG AND PLAY UNIT

All options are factory installed on the unit, which means that
they are ready for use, optimizing the time spent on site for the
installation. Bottom entry (through the base) for electrical power
and hot water (if option fi tted) lines are available as standard.
To make installation easier, FLEXAIR power supply does not
require "neutral" connection. It is powered by 400 V, 3 phases,
50 Hz.

Circuit breakers

To improve safety and extend life time, circuit breakers protect
against over-loading, over current and a disconnected supply
phase. Maintenance is also improved as there is no requirement to
change fuses. The electrical panel is manufactured in accordance
with EN60204 electrical directive.

Numbered wires

All wires and connectors are numbered as shown on the electrical
drawing to facilitate maintenance and diagnostic

Main disconnect switch

The main switch is used as an emergency cut off.
It is mandatory to guarantee a proper accessibility to this switch.
Specifi c footbridges must be installed if the machine environment
is requiring it.
Main disconnect switch is lockable to increase safety around
the rooftop unit.
Switching off the unit with the disconnect switch will reset all.
Disconnect switch will be sized accordingly to the options picked
with the unit.

Application Guide /FLEXAIR-AGU-1505-E

• 11 •

1- GENERAL DESCRIPTION

EASY ACCESS TO THE UNIT
COMPONENTS

In FLEXAIR we keep the accessibility of all the components to
the indoor unit, as well as all the internal refrigerant components

1.9. INDOOR AIR QUALITY

FILTERS

As standard the unit comes with EU3 fi lters
We can increase the capacity of fi ltration with an option of G4 and
an option of G4+ F7, to arrive offering an average arrestance of
synthetic dust above 90% (according to EN779:2012).

DOUBLE SKIN PANEL

As an option, indoor unit of FLEXAIR, can be provided by a
double skin panel, to avoid the carrying of insulation particles
inside the building (25mm of thickness).

EC FANS VENTILATION SISTEM

FLEXAIR is fi tted with EC fans as standard, ensuring that no

belt particles can be carried away into building .This ventilation
system is compliant with EN 13977 air quality norm.

ANALOGUE FILTER DETECTION

Thanks to this sensor, the fi lter presence and the proper fan
operation is ensured by a pressure drop above the minimum
threshold, and at the same time the fi lter dirtyness is identifi ed
by a pressure drop above the maximum threshold.

REMOVABLE ALUMINIUM DRAIN PAN

All units are equipped with a sloped removable drain pan in
aluminum which can be removed for maintenance, preventing
the growth of bacteria an algae in the drain pan.

• 12 •

Application Guide / FLEXAIR-AGU-1505-E

1- GENERAL DESCRIPTION

1.10- FRESH AIR AND FREE COOLING SYSTEM

Freecooling system is a standard feature for all Lennox rooftops,
with a two sections damper made in aluminum, and connected with
a proportional servomotor commanded by the control e-climatic
.

New buildings that comply with EPBD will have good thermal
insulation with high internal loads and will require cooling even
when outdoor temperatures are low.
Managing fresh air is mandatory in a building to control CO2
level and comfort.

Fresh air management and Free Cooling are standard features
of FLEXAIR that can reduce annual energy consumption.

SAVING ENERGY WITH FRESH AIR
& FREE COOLING

• Thermodynamic cooling can be replaced by Free Cooling
when outdoor temperature is below the building set point
saving up to 15% on annual energy consumption.

• Introducing just the required amount of Fresh Air in a building
can reduce energy consumption.

Because a fresh air damper curve is not linear, it is not accurate
to assume that the percentage of opening of the damper is equal
to the percentage of fresh air entering the building. However, this
linear control of a damper is by far the most used in the industry

With Indoor air quality and running cost of a building being more
important to our customer, FLEXAIR can manage the percentage
of fresh air more accurately.

100

90
80
70
60
50
40
30
20
10

Fresh air rate in % of supply airfl ow

Curve А : ΔP return ducts > Fresh air: Too much fresh air

Curve B : ΔP return ducts < Fresh air: Not enough fresh air

10 20 30 40 50 60 70 80 90 100

% Damper position

A

B

I

f the pressure drop in return air duct is high, the amount of fresh
air actually introduced in the building can be higher than required.
This extra fresh air will have to be cooled in summer and heated
in winter, increasing energy consumption of the system.

FLEXAIR will periodically recalibrates fresh air dampers to ensure
just the required amount of fresh air is introduced in the building.
This recalibration is achieved using the return air, outdoor air
and supply air sensors.

Application Guide /FLEXAIR-AGU-1505-E

• 13 •

2- OPTIONS DESCRIPTION

2.1- AUXILIARY HEATING OPTIONS

HOT WATER COILS

A water coil made of copper pipe and
aluminum fi ns can be installed to answer
heating requirements. This water coil
can, for example, be connected to a
boiler or a heat pump. Two sizes of
water coils are proposed to cope with
the cooling and heating requirements.
The water coil is equipped with a 3-way
valve.

To check the different capacities of the water coils, please
refer to the section "Heating auxiliary performances" of this

application guide.

The hot water coil are protected from freezing by the Climatic,
through low enviroment protections based on low supply and
external temperatures, which activates safety procedures lcve
pump starts, valve opening or return air damper opening.

ELECTRIC HEATER

The auxiliary electric heater is made
of shielded resistance heaters, which
are smooth 6 W/cm2 resistances.
The heater is protected against high
temperature with a thermal overload
protection set at 90°C 150mm after the
heating elements.
For any rooftop unit size, two sizes of

electric heater are available as option, S (standard) and H (high).

F Box: 85 to 120 Kw

Standard heat : 30 kW, 2 stages
Medium heat : 54 kW, fully modulating (Triac)
High heat : 72 kW, fully modulating (Triac)

GAS BURNER

FLEXAIR FAM and FAG units are

fi tted with a gas burner. It is a safe and
reliable atmospheric gas burner made
of aluminized steel tube heat exchanger
designed to offer maximum heat transfer
and 92% effi ciency (PCI%).
It runs with natural gas 20 mbar and an
operating range of 13-26 mbar.

The standard gas module offers 2 stages
of control which helps in improving space comfort by avoiding
large supply air temperature deviations. Where more capacity
control is required a modulating version is available with high
heat burner models. With the modulating gas burner the airfl ow
rate in the burner is controlled as the gas fl ow is being reduced
maintaining the burner to its highest effi ciency level.

If required, an expansion device can be provided with the unit
allowing it to operate with gas pressures of up to 300 mbar.

Gas fi red rooftop cannot be installed inside a technical room.

F Box: 85 to 120 Kw

Standard heat (two stages): 60 kW
High heat (modulating): 120 kW

G Box: 150 and 170 kW

Standard heat (two stages): 120 kW
High heat (modulating): 180 kW

H Box: 200 and 230 kW

Standard heat (two stages) : 180 kW
High heat (modulating): 240 kW

G Box: 150 and 170 kW

Standard heat : 45 kW, 2 stages
Medium heat : 72 kW, fully modulating (Triac)
High heat : 108 kW, fully modulating (Triac)

H Box: 200 and 230 kW

Standard heat : 72 kW, 2 stages
Medium heat : 108 kW, fully modulating (Triac)
High heat : 162 kW, fully modulating (Triac)

• 14 •

Application Guide / FLEXAIR-AGU-1505-E

2- OPTIONS DESCRIPTION

2.2- HEAT RECOVERY OPTIONS

FLEXAIR RECOVERY ON EXHAUST AIR (HEAT RECOVERY WHEEL)

To match Lennox commitment to a greener planet and to generate FLEXAIR savings FLEXAIR by Lennox can be equipped with one
system to recover FLEXAIR from the extraction air.

Ideal for climates in which the difference between the outdoor temperature and the extraction air temperature is high. This new hybrid
rotary wheel will generate very high sensible but also latent transfer.

Fresh air entry is protected with G4 fi lter.

2.3- FILTRATION OPTIONS

FLEXAIR offer several different levels of fi ltration that will allow
coping with every application and any level of fi ltration demanded
in the installation.

As standard the unit comes with EU3 fi lters

G4 fi lters, offered as standard can give an average arrestance of
synthetic dust above 90% (according to EN779:2012).

As an option, Lennox can offer :

- G4 50 mm metallic frame with replaceable media, for those
environments in which it is expected to change fi lters more
frequently than usual.

- G4 50 mm + F7 100 mm with 90% opacimetric effi ciency and
low pressure drop.

Application Guide /FLEXAIR-AGU-1505-E

• 15 •

2- OPTIONS DESCRIPTION

2.4- ELECTRICAL OPTIONS

ENTHALPY CONTROL AND CO2 SENSOR

This option includes combined temperature and humidity
sensors, to ensure that the economizer does not use 100%
fresh air if the outside air has a higher enthalpy than the return
air.

The CO2 sensor A VOC (Volatile Organic Component) detects
the amount of CO2 in the ambient air between 0 and 2000PPM.
(This obviously varies depending upon space occupancy levels).
The VOC sensor sends a proportional signal (0-20mA) to the
controller which will modulate the fresh air.

This option is highly reccomended in commercial installations
like restaurants, shops, etc., where the CO2 level strongly varies
during the day (e.g. depending on the people occupancy). In these
installations in fact the energy savings coming form the correct
air-renewal air-fl ow management (depending on CO2 level) can

defi nitively pay back this sensor cost in a very short time.

ENERGY METER

The FLEXAIR meter option is a device that measures and
displays the following parameters:

3 PHASE CONTROL

This phase control device offers the guarantee of the correct
phase connection, together with an overvoltage and under
voltage protection.

FIRE DETECTOR

It is a thermostat that provides a signal to switch off the unit,
close the fresh air damper and open the return damper when
the temperature in the return air stream is above an adjustable
set point (Factory setting: 70°C).

SMOKE DETECTOR

Located downstream of the fi lter, the optical head of the smoke
detector can detect any type of smoke. When this occurs the
unit will stop operating, the return air damper will be fully closed
and the fresh air damper will fully open while sending an alarm
signal to the unit.
In accordance with the European norm, it is also compliant with
the French regulation on public buildings.

• Average, total and maximum current, voltage and frequency
for each phase.

• Active & reactive power.

• Power factor (Cosφ).

• Total active & reactive FLEXAIR consumption in Wh.

Values for FLEXAIR, current and absorbed power can be reset
with password.

Some of these data will be collected by the controller and made
available in the BMS tables for Modbus, BACnet and Trend
protocols (not available for LonWorks).

• 16 •

Application Guide / FLEXAIR-AGU-1505-E

2- OPTIONS DESCRIPTION

2.5- CONTROL OPTIONS

DC™ COMFORT DISPLAY

This is a remote controller for
non-technical customer. It is
designed to fi t aesthetically
inside a room and be very easy
to use. It has a 24V supply to
be connected to the rooftop and
can be installed at maximum
30 meters away from the unit.

The graphical display gives
information such as running
mode of the unit, status of the
fan, set point, % of fresh air,

outside air temperature.
Customer can set the temperature set point for a given time
zone, switch the unit “On” or “Off” and adjust the clock. DC can
display fault codes with a reset possibility, ambient, supply and
outdoor temperature, fresh air damper position (%), time zone
and operating mode pictogram, heating or cooling status.
It is also able to display supply fan airfl ow rate (0-33-66-100%)
and component status for compressors, defrost, condenser fans
and auxiliary heaters.

DC™ comfort display is equipped with a temperature sensor
that can be used as room temperature sensor.

DM™ MULTI-ROOFTOP DISPLAY

COMMUNICATION INTERFACES AND
SUPERVISION:

The CLIMATIC ModBus interface is required to connect the unit
to a BMS using "ModBus protocol". No other hardware than this
board is required to have ModBus communication. One board
required per rooftop. The ModBus interface is available in two
versions to be connected with RS485 or TCP/IP depending on
site requirements.

This board is also mandatory for any connection between one
or several FLEXAIR units and Lennox ADALINK II, Lennox
OneWeb, Lennox Cloud service 3G or LennoxVision supervision
solutions. One BMS interface required per rooftop.

ADALINK II™

Adalink II™ is Lennox’s simplest solution for HVAC installation
supervision to better control the system and improve reliability
and energy effi ciency. One ADALINK II™ can control up to 32
Lennox units on the same site (Chillers, rooftop or any other
unit using controller and above). It displays a site picture with
the status of each unit and allows the user to change set points,
access alarm history and plot charts. It is the ideal tool to save
time and money on maintenance with an expert mode giving
access to all the parameters and set point of the unit.

• Easy local management of important settings

• Possibility to create macro commands to simplify setting and
better control the installation

• Easy scheduling by unit or by zone with a smart user friendly
drag and drop system

• Preventive maintenance to reduce downtime and improve
comfort and energy effi ciency at all time.

• Remote connection via LAN or 3G

• Site maintenance planning

This display gives access to more functionality than the DCTM
and allows managing up to 8 rooftops on a single Bus-wire.
Customer will be able to change the operating time zone and
mode. The rooftops can be connected to operate on a Master/
Slave principle. Installation up to 1000m from the unit.

DS™ SERVICE DISPLAY

This new plug and play service display and controller allows
service personal to set up to read and modify all unit parameters
(Unit settings, operating time and number of compressor starts,
low and high pressure reading, airfl ow rate of supply fan, and
read the history of last 32 faults...).

This controller has been designed to be very user friendly, with
6 different keys and graphic display. It includes scrolling menus
and full text (no codes) explanation. It is available in English or
another alternate language.

ADALINK II™ can also act as a real gateway to the unit, as it can
be used locally or via LAN network with ModBus TCP/IP protocol.

Any BMS can read and write information in the rooftops units using
ADALINK II™ network. Both systems can run at the same time.

Application Guide /FLEXAIR-AGU-1505-E

• 17 •

2- OPTIONS DESCRIPTION

2.6- REFRIGERATION OPTIONS

Low Noise Option

As rooftops are often installed in a noise sensitive area, LENNOX
proposes a low noise option on FLEXAIR. To achieve low noise
level, FLEXAIR receives a quieter fan, a compressor jacket and
is fully equipped with acoustic isolation in the refrigerating box.

2.7- FRESH AIR OPTIONS

As managing fresh air is becoming mandatory in most buildings
economiser is now fi tted as standard with the FLEXAIR.

Advanced control pack

Where a higher level of controllability is required to make the
FLEXAIR even more fl exible, LENNOX have compiled a pack
that includes two advanced control features.

• "Enthalpy control on economiser".

The eCLIMATIC and its humidity sensors (return air and fresh

air) ensures that the economiser does not use 100% fresh
air if the outside air has a higher enthalpy than the return air.
This feature is relevant in regions where the relative humidity
is high or when the desired room air condition is very dry.

Anti corrosion protection

When the units are installed in potentially aggressive
environments, which can often be the case for example in coastal
environments, it is often a requirement that the coils are specially
treated to protect them against the corrosive effects.
LenGuard™ anti-corrosion treatment is available for condensers,
evaporators and hot water coil.

Indoor air quality sensor

Indoor air quality is controlled from the eCLIMATIC main
controller. A VOC (Volatile Organic Component) sensor detects
the amount of CO2 in the ambient air between 0 and 2000PPM.
(This obviously varies depending upon space occupancy levels).
The VOC sensor sends a proportional signal (0-20mA) to the
eCLIMATIC controller which will then modulate the fresh air.

• "Humidity control"

The eCLIMATIC and its humidity sensors, analyze dry and

wet bulb temperatures to control dehumidifi cation. Humidity
control is only available if ambient temperature is in cooling
or dead zone. The dehumidifi cation algorithm can dry the air
by passing it through the coil in cooling mode.

A specifi c function in the program can be activated to control

the minimum supply air temperature, by maintaining it equal
to the heating set point, using auxiliary heaters (Electric, Hot
water coil or gas burner).

A proportional 0-10V contact is also available to control an

external humidifi er.

• 18 •

Application Guide / FLEXAIR-AGU-1505-E

2- OPTIONS DESCRIPTION

2.8- AIRFLOW CONFIGURATIONS AND ROOFCURBS

BASIC AIRFLOW CONFIGURATIONS

Standard

Unless specifi ed otherwise when ordered, FLEXAIR rooftops
are shipped with downfl ow supply and return confi guration.
Units can be confi gured before shipment with the required
airfl ow confi gurations to suit the building needs.

AIR SOCK CONTROL

A standard feature in FLEXAIR, EC fan regulation allow the air
socks to be progressively fi lled with air on start up. It takes one
minute to go from 0% of air to Nominal airfl ow rate

ROOFCURBS

Non adjustable non assembled roofcurb.

A sturdy mounting frame designed for single package units
providing an automatic weatherproof sealed rooftop installation.
This roofcurb is shipped knocked down and must be assembled
on site.

Adjustable roofcurb.

This adjustable and assembled roofcurb is made of galvanized
steel with 2.5 mm. This adjustable roofcurb is designed to be
installed in roofs with slopes up to 4 to 5% in all directions,
enabling FLEXAIR to be compatible with most roof profi les.

Downfl ow roofcurbs are the easiest and the cheapest way to install
packaged air conditioning systems to a single volume building.

The frame can be secured directly to the roof structure thanks
to its built in adjustable fl anges and sealing liner returns

Multidirectional roofcurb

This option is a required when customer wants to have horizontal
return and horizontal supply on the same side.
It is also required with the power exhaust fan or gravity exhaust
damper options combined with horizontal return fl ow confi guration.

5%

Rooftop

Roofcurb

Thermal insulation

5%

50

Sealing

400 mm minimum

Application Guide /FLEXAIR-AGU-1505-E

• 19 •

2- OPTIONS DESCRIPTION

2.9- EXTRACTION OPTIONS

UNIT WITH NO EXHAUST AIR OPTION

1 → 2 : ESP (external static pressure) given in eLencal (LENNOX
units selection tool) corresponds to the static pressure between
inlet and outlet of the unit and includes all options and accessories
delivered with the unit with the exception of the ductwork. This
external static pressure will be used to push the air through the
supply and the return ductwork installed on site.

ESP =

Supply duct pressure drop + return duct pressure drop

Example :

With an eLencal ESP = 350 Pa and a return ductwork pressure
drop of 150 Pa ▬► Remaining available static pressure for the
supply ductwork = 200 Pa

In any case, on a basic unit, the return ductwork pressure drop
should be lower than 150 Pa.

The airfl ow is usually set during start up for a given fresh air
rate. During normal operation the fresh air ratio will change and
eventually the unit will go to full fresh air during free cooling
operation. If the pressure drop in the return ductwork is high,
the fan may trip on over current protection when it operates with
full fresh air where the pressure drop is much lower.

If the return ductwork pressure drop is higher than 150 Pa :

• Select an extraction roofcurb which will include an extraction
fan and the appropriate drive kit for the given airfl ow and
pressure drop.

• FLEXAIR with eDRIVE includes constant airfl ow operation
that can control and limit the airfl ow as the pressure drop
reduces.

Building air tightness Low air tightness

Fresh air & Free cooling

Pressure drop in the
return ductwork

Medium fresh air rate
Free cooling possible

Medium < 150 Pa

2

1

GRAVITY EXHAUST DAMPER

1 → 2: ESP “Supply” in eLencal
Gravity exhaust dampers are used to relief pressure when outside
air is being introduced in a building with good air tightness.

Building air tightness Medium

Fresh air & Free cooling

Pressure drop in the
return ductwork

Building pressure control Low control

Typical applications Warehouses

High fresh air rate
Free cooling

Low < 50 Pa

Building pressure control NO control

Typical applications

• 20 •

Existing hypermarkets and supermarkets
(old buildings with high leakage rates)

2

Application Guide / FLEXAIR-AGU-1505-E

1

2- OPTIONS DESCRIPTION

POWER EXHAUST FAN

1 → 2: ESP “Supply” in eLencal.
Power exhaust axial fans with gravity exhaust dampers provide
exhaust air pressure relief when high levels of outside air are
being introduced in the building with good air tightness.
It is interlocked to run when return air dampers are being closed
and supply air blower is in operation. The power exhaust fan runs
when outdoor air dampers are at least 50% open (adjustable
by set point). It is also overload protected. A gravity exhaust
damper is supplied with this option to prevent air from entering
the unit when fan is off.

Building air tightness Medium

Fresh air & Free cooling

Pressure drop in the
return ductwork

Building pressure control Low control

High fresh air rate
Free cooling

Medium 50 Pa to 150 Pa

EXTRACTION ROOFCURB

1 → 3: ESP Return in eLencal
3 → 2: ESP Supply in eLencal
Where system balancing is critical and return ductwork pressure
drop is high, it is recommended to use extraction fan such as
the one located in the extraction roofcurb.
A plug fan installed with a 3rd damper (1 inside the Roofcurb
+ 2 inside the rooftop), is able to extract up to 300 Pa with the
Nominal airfl ow rate of the unit. This roof curb can be used in
either horizontal or downfl ow applications.

Building air tightness High

Fresh air & Free cooling

Pressure drop in the
return ductwork

Building pressure control Pressure balance possible

High fresh air rate
Free cooling

High > 150 Pa

Typical applications Light commercial, petrol stations...

2

1

Typical applications

Theatres, cinemas, data centres, new air
tight buildings with long return ductworks

Application Guide /FLEXAIR-AGU-1505-E

21

• 21 •

3- GENERAL DATA

FAC FAH

Cooling only Heat pump

FAG FAM

Cooling only with gas fi red heating Heat pump rooftop with gas fi red heating

FLEXAIR 085 100 120

Casing F BOX

3

Nominal airfl ow rate m

Cooling mode (FAC - FAG)

Gross cooling capacity

(1)

Compressor gross power input

Indoor fan absorbed power

Full load amps

(1)

FAC 2,71 4,08 5,28

FAG 3,26 5,14 6,65

Direct start up amps ratio Id/Ia

Gross EER

Global net EER

(2)

(3)

Cooling mode (FAH - FAM)

Gross cooling capacity

(1)

Compressor gross power input

Indoor fan absorbed power

Gross EER

Global net EER

(2)

(3)

FAH 2,71 4,08 5,28

FAM 3,26 5,14 6,65

Heating mode (FAH - FAM)

Net heating capacity

FAH 78,4 94,7 109,0

Compressor gross power input

Indoor fan absorbed power

Gross COP

Global net COP

(2)

(3)

FAH 2,71 4,08 5,28

FAM 3,26 5,14 6,65

Heating - Gas fi red

(4)

Heating capacity kW

Power input kW

S

(4)

H

(4)

S

(4)

H

Thermal effi ciency %

(4)

Gas fl ow (for natural gas at 20 mbar and 15 °C) m

S

(4)

H

Refrigeration circuit

Number of circuits

Compressor type and number

Expansion valve number

Refrigerant charge per circuit 1/2 kg

FAC-FAG

FAH-FAM

Ventilation data

Nominal airfl ow rate

Maximum airfl ow rate

External static pressure / Maximum

(1) All data are at Eurovent conditions (400V/3Ph/50Hz at nominal airfl ow rate),

nominal external static pressure.

Cooling :

• Outdoor temperature = 35°C DB

• Entering coil temperature 27°C DB / 19°C WB

Heating :

• Outdoor temperature = 7°C DB / 6°C WB

• Indoor temperature = 20°C DB

(5)

/h

15000 18500 20500

86,0 101,3 119,3

kW

A

20,1 27,1 31,4

67,5 75,5 103,2

209,3 252,3 293,9

FAC 3,56 3,30 3,29

FAC 3,24 2,92 2,85

FAG 3,15 2,80 2,73

85,0 100,0 117,5

kW

20,6 27,1 31,3

FAH 3,52 3,26 3,24

FAH 3,20 2,88 2,81

FAM 3,11 2,76 2,69

kW

18,3 22,9 28,6

FAH 3,60 3,58 3,26

FAH 3,39 3,32 3,01

FAM 3,34 3,24 2,94

55,2

110,4

60

120

92

3

/h

6,3

12,5

1 scroll + 1 scroll

2

9 / 9 9,1 / 9,1 9,1 / 9,1

9,1 / 9,1 9,2 / 9,2 9,2 / 9,2

15000 18500 20500

3

m

/hMinimum airfl ow rate

12000 14000 15000

23000 23000 23000

Pa

(2) Including compressor + outdoor axial fan + indoor centrifugal fan

(3) Net COP = Net cooling capacity/Total absorbed power

(4) S = Standard heat / H = High heat

(5) At nominal airfl ow rate

150 / 800 150 / 800 150 / 800

• 22 •

Application Guide / FLEXAIR-AGU-1505-E