Zehnder Rittling ComfoAir XL Series Guide

Cooling FilteringHeating Ventilation
Technical documentation
ComfoAir XL 800-6000
The latest generation of ventilation units with heat recovery

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Service and recommendations
The latest heat recovery range from Zehnder is called ComfoAir XL.
This range provides a healthy and pleasant indoor climate especially for use in commercial buildings and
apartment blocks.
There are numerous options with regard to the range of versions, control system technology, options and
accessories. You can also arrange your unit combinations yourself. We are pleased to help you achieve your
optimal ventilation system.
We would be delighted to support you:
■Detailed recommendations based on a special operating point/with price details
■Support in the project (draft and implementation)
■Instructions on ventilation systems
■Telephone/personal assistance
People in a perfect indoor climate: for a nicer living area, work area and living environment.
We give you our word. Zehnder ‘always around you’.
All rights reserved.
Utmost care and attention has been taken to create this document; however, the publisher cannot be held liable
for any damage arising from missing or incorrect representation of information in this document. In the case of
dispute, the Dutch version of the text shall have priority.

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Table of contents
1. General ......................................................................................................................................................................4
1.1 Important features............................................................................................................................................... 4
1.2 Passive house certification..................................................................................................................................4
1.3 ComfoAir XL series and options .........................................................................................................................4
1.4 Block diagram .....................................................................................................................................................5
2. Set-up ........................................................................................................................................................................ 6
2.1 Air-tight housing..................................................................................................................................................6
2.2 Fans .................................................................................................................................................................... 7
2.3 High-performance plate heat exchanger ............................................................................................................7
2.4 Siphon ................................................................................................................................................................ 7
2.5 Bypass ................................................................................................................................................................ 7
2.6 Filter .................................................................................................................................................................... 7
2.7 Batteries.............................................................................................................................................................. 8
2.8 Flaps ...................................................................................................................................................................8
2.9 Design .................................................................................................................................................................9
3 Control unit ............................................................................................................................................................. 10
3.1 Controller .......................................................................................................................................................... 10
3.2 Supply ............................................................................................................................................................... 10
4. Quick selection....................................................................................................................................................... 11
4.1 C od in g ............................................................................................................................................................... 11
4.2 Selection schematic .......................................................................................................................................... 11
4.3 Selection chart .................................................................................................................................................. 12
5. Dimensions and weight.......................................................................................................................................... 14
5.1 Indoor installation.............................................................................................................................................. 14
5.2 Exterior mounting ............................................................................................................................................. 15
6. Technical data ........................................................................................................................................................ 16
6.1 Technical data ComfoAir XL 800 ....................................................................................................................... 16
6.2 Technical data ComfoAir XL 1500 ..................................................................................................................... 18
6.3 Technical data ComfoAir XL 2200 ..................................................................................................................... 20
6.4 Technical data ComfoAir XL 3300 ..................................................................................................................... 22
6.5 Technical data ComfoAir XL 4400 ..................................................................................................................... 24
6.6 Technical data ComfoAir XL 6000 ..................................................................................................................... 26
7. Accessories............................................................................................................................................................. 28

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1. General
The ComfoAir XL series is a new generation of heat
recovery units, which is suitable for use in commercial
buildings and/or in apartment buildings. The ComfoAir XL
series covers 6 different capacities from 800 to 6000 m³/h.
1.1 Important features
■ Heat recovery of approx. 90 %
■ Capacity up to 6000 m³/h
■ Equipped with 100 % bypass
■ Passive house certification
■ Renewed controller (ModBus communication)
■ Constant volume and pressure control possible
■ Unique, air-tight housing
■ Renewed filter concept
■ Filter monitoring with pressure sensors
■ Easily accessible connection PCB
■ Unit easy to configure at specific operating point
■ Diaphragm siphon installed as standard
1.2 Passive house certification
The ComfoAir XL units were
designed in cooperation with
the Passive House Institute
(PHI) and in accordance with its
directives. The units have
passive house certification.
This means that they satisfy the
stringent requirements applied
by the Passive House Institute, whereby this series
achieves greater energy savings (25 %) than the
previous generation. The specific SFP value (specific
fan output) is less than 0.34 W/(m³/h).
1.3 ComfoAir XL series and options
The ComfoAir XL series is available in a variety of
versions and with numerous options. The focus was
placed on the smallest possible dimensions during
development of the units.
Versions:
■ ComfoAir XL 800
■ ComfoAir XL 1500
■ ComfoAir XL 2200
■ ComfoAir XL 3300
■ ComfoAir XL 4400
■ ComfoAir XL 6000
Mounting:
■ Indoor installation (I)
■ Outdoor installation (A)
Air direction:
■ Left (L)
■ Right (R)
Air direction for left-side version
The intake opening for the outside air is located at
the top right and the outlet opening for the used air
is located at the top left. The extract air is located at
the bottom right and the air supply at the bottom left.
Air direction for right-side version
The intake opening for the outside air is located at
the top left and the outlet opening for the used air is
located at the top right. The extract air is located at
the bottom left and the air supply at the bottom right.
Filter:
■ Cellular filter F7/G4 (PF)
■ Bag filter F7/G4 (BF)
Options:
■ Bypass:
- Bypass open/closed (B)
- Bypass modulating (BM)
■ Pre-heater (PRH)
■ Post-heater (POH)
■ Cooler (CL)
■ Outside air flap (DMP-ODA)
■ Exhaust air flap (DMP-EHA)
1EHA = Exhaust air
2SUP = Supply air
3ODA = Outdoor air
4ETA = Extract air
EHA1
SUP2
EHA1
SUP2
ODA3
ETA4
ODA3
ETA4

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1.4 Block diagram
- Filter
- Heater
- Cooler
- Heat exchanger
- Fan
- Temperature sensor
- Bypass
- Flap
ODA - Outside air
EHA - Exhaust air
ETA - Extract air
SUP - Supply air

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2. Set-up
2.1 Air-tight housing
The housing of the ComfoAir XL has a unique quality.
The double seals on the panels ensure that the
housing is perfectly air tight. The housing comprises
a self-supporting structure that is made from double-
walled panels with internal insulation that is 44 mm
thick. The panels are produced from sendzimir sheet
with a weatherproof Plastisol coating (Goosewing
Grey – RAL 7044) applied to the outside. A special
polyester coating (RAL 7035) is applied to the inside.
These panels are free from thermal bridges and
guarantee excellent insulation of the housing. The
draft focusses on compliance with the Passive House
Directive (internal and external leaks lower than 3 %).
An overview of the specifications is provided below.
Feature Class
Mechanical strength 2A
Internal leak (at 400 Pa) < 3 % of the nominal volume
External leak (at 400 Pa) < 3 % of the nominal volume
Thermal insulation T2 (0,51 Wm2/K)
Thermal bridge factor TB1
Fire resistant B
Angled profile
1. Foam
2. Sendzimir sheet 0.7 mm with Plasticol coat
RAL 7044
3. Sendzimir sheet 1.0 mm with powder coating
RAL 7035
4. Plastic profile with rubber shaft seal
5. Rubber shaft seal
6. Plastic tubes
7. M8 screw
8. M8 nut
Intermediate profile
1. Polyurethane foam. Insulation thickness 40 kg/m3
2. Outer skin: 0.7 mm pre-coated, galvanized sheet steel with Plastisol coating
3. Internal coating: 1.0 mm pre-coated, galvanized sheet steel RAL 7035
4. Plastic profile with rubber sealing lip
5. Dual rubber sealing tape
6. Plastic connection tube
7. M8 screw
8. M8 nut
9. Aluminium sealing profile
10. Thermal PE insulating foam

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2.2 Fans
The ComfoAir XL series consists of directly driven,
energy-saving EC fans with backward-curved blades.
These fans achieve an energy saving of more than
25% compared to conventional AC fans. These fans
are mounted vibration-free onto a mounting bracket.
This obviates the need for flexible sleeves to ensure
a vibration-free connection of the air ducts.
Error message
An alarm function is included in the control board as
standard. This alarm function is activated if a fan
fails. The error message can also be activated by
measuring the pressure difference via the supply air
filter if desired.
2.3 High-performance plate heat
exchanger
The HR cross-counterflow heat exchanger (HR plate
heat exchanger) is made of high-grade aluminium
and has a thermal efficiency of approx. 90 %
depending on the outside temperature and the air
humidity in the rooms. The exchanger is corrosion-
free and resistant to seawater and can be fully
recycled.
Benefits of a high-performance plate heat exchanger:
■ No wear
■ Easy to maintain
■ 100 % separate air streams
■ Low risk of contamination
Extract
air
Supply air
Exhaust
air
Outside air
Frost protection
Under certain circumstances, condensate can freeze.
To prevent this, frost protection is incorporated. This
shuts down the supply fan when there is a risk of
frost and can deactivate it for a short period.
2.4 Siphon
A siphon is installed to remove condensate that
forms in the plate heat exchanger.
An external diaphragm siphon must be connected to
remove the condensate that forms on the cooler. The
siphon can be kept frost-free by using an insulated
ribbon heating element. The contact for supply and
control can be set in the software.
2.5 Bypass
ComfoAir XL is equipped with a 100 % bypass. The
control unit of the ComfoAir XL automatically brings
the bypass valve to the closed and open positions.
This bypass is located near the heat exchanger and
is controlled by a counter-rotating bypass valve,
which is controlled automatically by a servo motor.
When the bypass valve opens, the extract air flows
around the high-performance plate heat exchanger
and no thermal transfer takes place. The filter system
continues to work, however. In this way, it is possible
to use what is referred to as 'free cooling' or night
ventilation in the evening and during the night.
Please also refer to the block diagram in chapter 1,
section 4 for details of bypass operation.
Open/closed or modulating bypass
ComfoAir XL can be equipped with an open/closed
or modulating bypass. The servomotor regulates the
modulating bypass and ensures that the temperature
of the supply air is constant. This is particularly
important when the unit has a cooling battery.
2.6 Filter
Two types of filters are available for filtering the
supply and exhaust air flows: one cellular filter and a
bag filter. The supply air flow is equipped with a F7
filter as standard, the exhaust air flow is equipped
with a G4 filter. With the newly developed filter
clamps, the filters are mounted onto the filter frame,
which minimises leaks. The units are equipped with a
filter monitor as standard. This is achieved with
pressure sensors that measure the resistance via a
filter to issue dirt notification.

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2.7 Batteries
The ComfoAir XL series can optionally be equipped
with a pre-heater and post-heater or cooler.
The battery connections are attached outside the
unit. The control unit for these batteries is set up to
be equipped with several power relays (230 V) and
0-10-volt outputs via the connection board of the
unit. The connection board issues a 0-10 V signal to
control the two-way valve. The power relay (230 V) is
used to supply the circulation pump.
The batteries must be connected to an externally fed
cold and/or hot water supply. All batteries must be
selected on a project-related basis.
Pre-heater
A pre-heater can be attached to
pre-heat the cold outside air in winter.
This heating battery is positioned in
front of the heat exchanger and can be
used as a frost protection system. The
preheater is calculated on the basis of
the water/glycol medium to prevent the
battery from freezing.
Post-heater
The post-heater increases the
temperature of the supply air. In this
way, air can be blown in at a higher
comfort temperature. The post-heater
is located behind the heat exchanger
in the direction of the air flow.
Cooling battery
A cooling battery is used to cool
the supply air. This battery is
positioned behind the heat
exchanger like the post-heater.
The cooling battery is mounted on
the drain plate to collect
condensate. A polypropylene
droplet catcher that runs to the
drain plate is positioned behind
the cooling battery in the direction
of air flow.
2.8 Flaps
Flaps can be used to protect the unit
against outside influences when it is
not in operation. The intake can be
equipped with a lockable flap either
for the outside air or the exhaust air.

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2.9 Design
AB C
C
D
E F
G
HII
J
Q QK
L
M N OP
J
ComfoAir XL is equipped with the following components as standard:
■ A: Plate heat exchanger with high-performance heat recovery
■ B: Drain plate below the plate heat exchanger with siphon
■ C: Two EC fans with backward-curved blades
■ D: Main board
■ E: Connection PCB
■ F: Operating switch
ComfoAir XL is equipped with the following components as standard for mounting indoors:
■ G: Metal support frame
ComfoAir XL is equipped with the following components as standard for mounting outdoors:
■ G: Support frame made of galvanised metal
■ H: Coated metallic cover
■ I: Two droplet catchers
Options:
■ J: Panel or bag filter, filter class 7 for outside air and G4 for extract air
■ K: Bypass valve open/closed or equipped with modulating servomotor
■ L: Pre-heater to ensure controlled ventilation
■ M: Post-heater for enhanced comfort
■ N: Chiller for dehumidifying and cooling the supply air
- O: Droplet catcher behind the cooler to collect moisture
- P: Drain plate with condensate drain below the chiller
■ Q: Flap with servomotor

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3 Control unit
3.1 Controller
ComfoAir XL is equipped with a multifunctional
controller. The control unit comprises two different
PCBs. The main board, to which all internal
components can be connected, is located inside the
unit. All external functions are bundled at the
connection PCB. This is located behind the designer
front panel and is easily accessible to implement
numerous connections. The units have an automatic
frost-protection.
Essential features:
■ Connection to the building technology via ModBus communication
■ Constant Air Flow: to set fixed capacities
■ Filter monitoring: Pressure sensors measure the resistance via the filter
■ The unit software is equipped with a timeswitch as standard
■ Control via external sensor: CO2, pressure, relative air humidity
■ Various connections: 230 V, power relay
■ Generation of summer night cooling via digital input
■ Compatible with fire alarm system via digital input
■ Summer night cooling: activation via an external signal
■ Frost protection for the high-performance plate heat exchanger:
the supply fan is shut down when there is a risk of frost
ComfoAir XL is easy to change over from constant air
volume control to pressure control. This type of
control requires a pressure sensor to measure the
pressure in the supply air or extract air duct.
3.2 Supply
An integrated operating switch is located at
the operating side of the ComfoAir XL unit.
The connection terminals and connection board are
located behind the designer front panel. The board is
equipped with a display as standard, which can be
used easily to set the desired operating point.
The power supply is connected to the operating
switch. All versions, except for ComfoAir XL 6000,
are equipped with a 230 V/50 Hz/1~ power supply.
ComfoAir XL 6000 must be equipped with a
400 V/50 Hz/3~ power supply.