Zehnder Rittling ComfoAir 70 User manual

Decorative Radiators Comfortable indoor ventilation Heating and cooling ceiling systems Clean air solutions
User manual on operation and installation for operators and installers
Zehnder
ComfoAir 70

EN
Legal regulations
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This user manual has been compiled with the utmost care. Nevertheless, the publisher accepts no liability for damage
caused by missing or incorrect details in this manual. We reserve the right at any time and without previous notification to
change the content of these instructions in part or as a whole.
The information contained in these documents is the property of Zehnder Group. Publication, as a whole or in parts,
requires the written approval of Zehnder Group. In-house duplication, designated for the evaluation of the product or for
proper use, is permitted and not subject to approval.
Zehnder manufacturer's warranty
The current warranty terms can be obtained in paper form using the normal distribution channels.
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sign is free of trademark rights.
© 2021 Zehnder Group
Product video on installation and function

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Contents
1  Foreword and introduction .................................................................................................................. 2 
 Notes on the user manual....................................................................................................................... 2 
 Validity .................................................................................................................................................... 2 
 Target groups ......................................................................................................................................... 2 
 Qualification of target group.................................................................................................................... 2 
 Conformity .............................................................................................................................................. 2 
2  Introduction and safety ........................................................................................................................ 3 
 Hazard classification............................................................................................................................... 3 
 Safety regulations ................................................................................................................................... 3 
 Installation conditions ............................................................................................................................. 3 
 Notes on the operational safety of the ventilation unit ............................................................................ 3 
 Operation with fireplaces ........................................................................................................................ 3 
 Commissioning and operation ................................................................................................................ 3 
 Notes on operation of the ventilation unit................................................................................................ 4 
 Standard operation of the unit ................................................................................................................ 4 
 Operating variants .................................................................................................................................. 4 
 Proper use .............................................................................................................................................. 4 
 Guarantee conditions, warranty and liability ........................................................................................... 4 
 Guarantee conditions.............................................................................................................................. 4 
 Warranty ................................................................................................................................................. 4 
 Liability.................................................................................................................................................... 4 
 Storage ................................................................................................................................................... 5 
 Environmentally friendly disposal............................................................................................................ 5 
3  Chapter for operators and qualified personnel.................................................................................. 5 
 Product description ................................................................................................................................. 5 
 Unit design and function ......................................................................................................................... 5 
 Overview of assemblies.......................................................................................................................... 6 
 Type label ............................................................................................................................................... 6 
 Frost protection....................................................................................................................................... 6 
 Operating and display elements of the control panel .............................................................................. 6 
 Description of the operating functions and signals ................................................................................. 7 
 Options for ventilation operation ........................................................................................................... 10 
 External control panel ........................................................................................................................... 10 
 Operation via networking ...................................................................................................................... 10 
 Automatic operation via sensor module................................................................................................ 10 
 Maintenance by the user ...................................................................................................................... 11 
 Filter maintenance ................................................................................................................................ 11 
 Unit maintenance.................................................................................................................................. 13 
 What should I do in case of a malfunction? .......................................................................................... 13 
4  Chapter for qualified personnel......................................................................................................... 14 
 Installation requirements....................................................................................................................... 14 
 Packaging and handling ....................................................................................................................... 14 
 Checking the scope of delivery ............................................................................................................. 14 
 Installation ............................................................................................................................................ 14 
 General installation requirements ......................................................................................................... 14 
 Installation preparations........................................................................................................................ 15 
 Connecting ventilation tubes................................................................................................................. 15 
 Installing the ventilation unit.................................................................................................................. 17 
 Electrical connections ........................................................................................................................... 20 
 Parameterisation of boost ventilation and absent operating modes...................................................... 22 
 Configuration of the boost ventilation mode.......................................................................................... 22 
 Configuration of the Away mode........................................................................................................... 22 
 Installing the exterior wall panel as a facade finish............................................................................... 22 
 Commissioning ..................................................................................................................................... 24 
 Specialist maintenance......................................................................................................................... 24 
 Visualization of fault notifications .......................................................................................................... 25 
 Technical specifications........................................................................................................................ 26 
 Pressure loss-Volume Flow-Characteristic curves for design of adjoining room connection ................ 26 
 Dimensions with optional radio module ................................................................................................ 27 
 Terminal scheme .................................................................................................................................. 28 

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1 Foreword and introduction
Notes on the user manual
This translation of the original user manual contains basic instructions that must be followed during the installation and
operation of the ComfoAir 70 ventilation unit.
Read the instructions in full before installing and commissioning the ventilation unit. This will help you avoid hazards
and errors.
Provide the manual to the operator after the final assembly.
The user manual forms a part of the product. Keep the manual for future reference.
WARNING
Be sure to observe all safety notes, warnings and information on precautionary measures.
Read chapter “2 Introduction and safety” carefully.
Validity
This document applies to:
Unit type ComfoAir 70 series
The unit type series are hereinafter designated with the common product name, ComfoAir 70.
The subject of this user manual is the ComfoAir 70 in series production. Accessories are only described to the extent
necessary for appropriate operation of the unit. Please refer to the respective instructions for further information on
accessory parts.
Target groups
This manual is for users and qualified personnel. The activities are only allowed to be carried out by appropriately trained
personnel who are sufficiently qualified for the respective work involved.
Qualification of target group
1.3.1.1 Users
Users must be instructed by qualified personnel as follows:
Instruction in hazards when handling electrical devices.
Instructions on the operation of the ComfoAir 70.
Instruction in the maintenance of the ComfoAir 70.
Knowledge of and compliance with this manual, including all safety instructions.
1.3.1.2 Qualified personnel
Qualified personnel must have the following qualifications:
Training in dealing with hazards and risks when installing and operating electrical devices
Training for the installation and commissioning of electrical devices
Knowledge of and compliance with the locally applicable building, safety and installation regulations of the relevant
local authorities or municipalities, the regulations of the water and electric utilities, and other official regulations and
guidelines
Knowledge of and compliance with this document, including all safety instructions.
WARNING
Unless otherwise specified in this user manual, only a qualified person is authorised to install and commission the
ventilation unit and to carry out servicing.
Conformity
The ComfoAir 70 series ventilation units from the manufacturer
PAUL Wärmerückgewinnung GmbH
August-Horch-Straße 7
08141 Reinsdorf
Germany
Chemnitz commercial register 21371
comply with the directives and standards of the EU and EAC Declaration of Conformity.

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2 Introduction and safety
This manual contains information that must be observed for your personal safety and in order to prevent personal injury
and damage to property. This information is highlighted in the form of warning notes, which are shown below according to
the degree of risk.
Hazard classification
DANGER
This signal word indicates a hazard with a high level of risk which, if not avoided, will result in death or serious injury.
WARNING
This signal word indicates a hazard with a medium level of risk which, if not avoided, will result in death or serious injury.
CAUTION
This signal word indicates a hazard with a low level of risk which, if not avoided, will result in a minor or moderate injury.
NOTE
In the meaning of this manual, a note includes important information about the product or the respective section of the
manual to which special attention is drawn.
Safety regulations
Always observe the safety regulations and installation conditions. Failure to observe the safety regulations, installation
conditions, instructions, warnings, and comments in this document can result in personal injury or damage to the unit.
Do not make any changes to the unit or to the specifications listed in this document. Such changes can cause personal
injury or lead to reduced performance in the ventilation system.
Comply with the general locally applicable building, fire, safety and installation regulations of the relevant local
authorities, the regulations of the water and electric utilities and all other official regulations.
Installation, commissioning, and maintenance must be carried out by an authorized person or company, unless
otherwise stated in this document.
Do not disconnect the unit from the power supply unless instructions to the contrary are listed in the manual.
Following installation, all parts that could lead to personal injury are protected by the housing. The unit cannot be
opened without the use of a tool.
Only operate the ventilation unit with the filters inserted, the housing closed and the facade finish applied.
Installation conditions
The acceptable temperature range for the air being moved is between -20 °C and +40 °C
The unit must not be installed in rooms subject to explosion hazards
When installing the unit, make sure that the applicable country-specific standards / regulations for compliance with
protection zones when installing electrical systems in rooms with a bathtub or a shower are observed!
The unit must not be used for extracting combustible or explosive gases
The unit must be connected to a fixed 230 VAC / 50-60 Hz power supply
To switch off from the mains, a disconnection system using a contact opening width in accordance with the conditions
from overvoltage category III for complete disconnection must be provided.
Check whether the electrical installation is suitable for the maximum power of the unit.
Check that the installation location of the unit meets the requirements in the “4.1 Installation requirements” chapter.
Notes on the operational safety of the ventilation unit
Operation with fireplaces
Joint operation with fireplaces depending on the indoor air is only permissible in combination with the corresponding
safety devices and in compliance with applicable laws, regulations, and standards.
Observe the applicable regulations in the respective country during planning and installation.
Commissioning and operation
Only operate the ventilation unit when it is installed.
Only operate the ventilation unit with filters fitted.
Only operate the ventilation unit with the upper design cover closed and engaged.
Only operate the ventilation unit with a facade finish.

4
WARNING
Risk of injury from touching the fan during operation
Without an exterior wall panel, the fan is freely accessible and there is a risk of contact.
Make sure that the ventilation unit is disconnected from the power supply.
Notes on operation of the ventilation unit
Standard operation of the unit
This unit can be used by children aged 8 and over and also persons with reduced physical, sensory or mental abilities, or
a lack of experience and knowledge provided that they are under supervision or have been instructed on the safe use of
the unit and understand the risks that result from it. Children must not play with the unit. Children must not carry out cleaning
and user maintenance without supervision.
Operating variants
The ComfoAir 70 offers the following variants that can be combined for convenient operation:
Operation on the unit – standard version with internal control panel.
Operation with ComfoLED – optional: External, wired control panel (max. cable length 25 m).
Radio-based operation – optional: Radio networking via RF module, connection hub and Zehnder Connect app.
NOTE
The external control panel and the connection hub are only suitable for use in indoor areas.
Proper use
The ComfoAir 70 is intended for the ventilation of living rooms and spaces with a similar use. Any other use or any
use beyond this is considered improper use.
The ventilation unit is intended for use in rooms with a humidity level of approx. 40% to approx. 70% RH. It must not
be installed in rooms where the relative air humidity is permanently above 80% during operation.
The ventilation unit is not suitable for smoke extraction or drying buildings, for rooms with aggressive and corrosive
gases or for rooms with extreme dust levels.
The ventilation unit may only be operated when fully assembled with all the components (including facade finish).
Intended use also includes observing all instructions in the user manual.
In the event of improper use, the Zehnder Group accepts no liability for any damage that may occur and no warranty for
the proper and functional operation of the ventilation unit.
Guarantee conditions, warranty and liability
Guarantee conditions
The manufacturer grants a guarantee of 24 months from installation or a maximum of 30 months from the date of
manufacture on the device. Warranty claims may only be asserted for material defects and/or design faults that have
occurred during the warranty period.
The costs of removal and installation on site are not covered by the warranty. The same applies to natural wear and tear.
Zehnder reserves the right to change the design and/or configuration of its products at any time with no obligation to adjust
products already supplied accordingly.
Warranty
In the event of a warranty claim, the unit must not be disassembled without the written consent of the manufacturer. Spare
parts are only covered by the warranty if they have been supplied by the manufacturer and fitted by an approved technician.
The warranty shall be null and void if:
The warranty period has elapsed.
The installation has not been carried out in accordance with the applicable regulations.
The unit is operated without a filter and without a facade finish.
Original parts have been replaced by non-original parts.
Unauthorised changes or modifications to the unit have been made.
The defects are due to improper installation, improper use or neglected maintenance of the system.
Liability
The ComfoAir 70 is intended for the ventilation of apartments, offices and similar rooms. Every other use is deemed as
"improper use", and can lead to damaging the ComfoAir 70, or to personal injury, for which the manufacturer cannot be
held liable.
The liability of the manufacturer becomes null and void in the following cases:
Failure to observe the instructions specified in this manual pertaining to safety, operation and maintenance.

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Modifications to the ventilation unit or the use of components that have not been approved or recommended by the
manufacturer.
Incorrect installation, improper use or contamination of the system.
Original parts have been replaced by non-original parts.
Operation of the unit without filters and without a facade finish.
Storage
NOTE
Store the ventilation unit in its original packaging in a dry place at temperatures between 0°C and +40°C.
Environmentally friendly disposal
NOTE
Packaging materials, consumables and waste equipment must be disposed of at the end of their useful life in accordance
with the applicable regulations in your country.
3 Chapter for operators and qualified personnel
Product description
The ComfoAir 70 is built to the current state of the art and the recognized safety regulations. The unit is subject to
continuous improvement and development. This is why it is possible for your unit to deviate slightly from the description.
Unit design and function
The ComfoAir 70 is a decentralised comfort ventilation unit, with heat and humidity recovery, using synchronous supply
and extract air operation. The ventilation unit can be used both for individual room ventilation (room-by-room) and, via
connection options for ventilation tubes, for venting of a group of rooms (utilisation unit). The ventilation unit is designed
for permanent operation and is only to be taken out of operation for maintenance and repair work. With the appropriate
(optional) sensor technology in the unit, fully automatic, demand-controlled ventilation operation is possible.
The housing consists of a powder-coated steel plate, as well as covers made of aluminium in the RAL9016 colour scheme.
The body of the unit, which is made of high-quality polypropylene (EPP), is used to house the main assemblies, provide
thermal insulation and sound protection for the unit.
The enthalpy exchanger used as standard in the unit ensures a healthy, comfortable indoor climate with its high heat and
moisture recovery.
Both of the maintenance-free centrifugal fans are driven by energy-efficient EC direct-current motors. The fan output in the
form of the air volume flow can be adjusted in four stages. In the automatic operating mode, the air volume flow is
continuously controlled.
A fully automatic shutter control activates the motorised shutters as required for standby and frost protection mode.
The ventilation unit requires very little maintenance, but it is important to change the air filter regularly. Inside the unit, there
is a filter with filter class ISO coarse 70% for the outdoor air and another one for the extract air in serial production.
Optionally, a filter of filter class ISO ePM10 80% can be used for filtering the outdoor air.
As a facade finish, an exterior wall panel is available in three different types of material: white aluminium, white ABS plastic,
or stainless steel.

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Overview of assemblies
Type label
The type label identifies the product unequivocally. The type label can be found underneath the upper design cover, on
the EPP housing unit. You will need the details on the type label for the safe use of the product and in case of questions
for service. The type label must be attached permanently on the product.
Frost protection
The ComfoAir 70 is equipped with an automatic frost protection function to prevent the thermal exchanger from icing up.
In working condition, the control unit acting in frost protection mode is activated when required for the four manual fan
speeds as well as in automatic mode.
Operating and display elements of the control panel
The control panel has touch-sensitive buttons and LED status indicators.
NOTE
The ventilation unit can be operated at the same time with the internal and the external control panel.
Item Description
A EPP housing, upper part
B Extract air filter ISO Coarse 70 %
C Filter cover made of cellular rubber
D Facade finish, external wall panel
E Wall bracket
F Enthalpy exchanger (diaphragm moisture heat exchanger)
G Terminal box, electrical connection
H EPP housing unit with integrated fans and folding mechanism
I Control board
J Lower design cover made of aluminium, with integrated control panel
K Touch-sensitive internal control panel
L Outdoor air filter ISO Coarse 70 % or ISO ePM10 80 %
M Filter cover made of cellular rubber
N Upper design cover made of aluminium
A C
B
F
N
M
D
K
J
I
H
L
E
G

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The two (+) / (-) keys are used for setting the various fan speeds and operating modes. The ventilation stages and the
Automatic operating mode are indicated with blue LEDs, and the service information with red LEDs.
Description of the operating functions and signals
Icon Description Explanation
Fan speed
operating mode
Manual
The selection for the current fan speed (in total 4 fan speeds with preset
speeds for each fan) is made by using the (+) / (-) buttons.
Touching the (+) button sets the next higher fan speed and touching the
(-) button sets the next lower fan speed.
LED1 lights up
Fan speed 1 (FS1)
Reduced ventilation
The ventilation unit runs at the lowest ventilation level (15 m³/h). This fan
speed can be selected when away and for the purpose of moisture
protection.
NOTE
A cyclically limited reduced ventilation can be set with the Away
operating mode.
LED1-2 light up
Fan speed 2 (FS2)
Nominal ventilation
The ventilation unit runs at a low ventilation level (25 m³/h). This is normal
operation, used to achieve the necessary ventilation for hygienic and
health requirements when users are present.
LED1-3 light up
Fan speed 3 (FS3)
Increased ventilation
The ventilation unit runs at a higher ventilation level (40 m³/h) to reduce
peak loads, e.g. when several people are present.
1 2 3
4
LED
Automatic
Symbol
Automatic
Symbol
Fault
Symbol
Filter
m
a
in
te
n
a
n
ce
LED
Filter maintenance
LED
Fan speeds
(+) / (-) buttons for
selecting operating mode /
fan speed
LED
Fault
1 2 3 4

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Icon Description Explanation
LED1-4 light up
Fan speed 4 (FS4) Intensive ventilation
The ventilation unit runs at maximum ventilation level (60 m³/h). This fan
speed is used for a fast air exchange.
NOTE
Intensive ventilation for a limited period of time can be set with the
boost ventilation operating mode.
AUTO LED lights up
Automatic
operating mode
(AUTO)
NOTE
The Automatic function can only be activated with a sensor module.
Touching the (+) key from the currently active FS4 transfers the unit to
AUTO fan speed. AUTO fan speed is excited by touching the (-) button,
and the unit is transferred back to FS4. The Automatic function is
visualized by the Automatic LED.
AUTO LED lights up
Bathroom function
operating mode
NOTE
The Bathroom function can only be activated with a sensor module
and configured DIP switch setting.
The fans are operated at maximum speed starting from a relative room
air humidity of 80%. If this limit is not reached, the previously active
operating mode is applied again.
LED1-4 light up
Boost ventilation
mode
NOTE
The boost ventilation function as temporarily activated fan speed 4 can
only be activated with a configured DIP switch setting.
After the boost ventilation time has elapsed, the unit will be transferred
to the most recently selected fan speed. The fan speed that was active
for longer than 10 s is deemed as the last fan speed. When boost
ventilation is active, the operating modes "Extract air mode" or "Supply
air mode", that may be activated, are retained.
The duration of the boost ventilation function can be set between 5 and
120 minutes by the customer service team using the programming
module.
(Factory setting: 15 minutes)
LED1 lights up
during the active
time phase
Away mode
NOTE
The Away function as temporarily activated fan speed 1 can only be
activated with a configured fan speed 1.
The active operating time of the FS1 can be set between 15 and 59 min/h
by the customer service team using the programming module.
(Factory setting: 60 min/h ≙FS1 permanent operation).
LED display for
energy-saving
mode
The LED display on the control panel changes after 10 seconds into
energy-saving mode without operator input (unit functions remain active;
the LED display is switched off). If any key is touched, the LED indicator
will be activated again. Touching the button brings about no change to
the operating mode, however.

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Icon Description Explanation
Standby mode The unit can be switched from FS1 to Standby mode by touching the (-)
button. The fans then come to a stop.
NOTE
The shutters are closed automatically.
Standby mode is excited by touching the (+) button. The unit will start
with fan speed 1.
NOTE
The shutters are opened automatically.
There is no indication of the Standby mode from the LEDs of the control
panel.
LED1 flashes in
alternation with the
current fan speed
Extract air mode Touching the (-) key for 5 seconds in operating modes FS1 to FS4
activates or deactivates the Extract air mode. The supply air fan is
switched off; the extract air fan continues to run with the current fan
speed.
The display for the current fan speed alternates every 2 seconds with the
flashing LED1.
LED4 flashes in
alternation with the
current fan speed
Supply air mode Touching the (+) key for 5 seconds in operating modes FS1 to FS4
activates or deactivates the Supply air mode. The extract air fan is
switched off; the supply air fan continues to run with the current fan
speed.
If the outdoor temperature falls below 13 °C, the extract air fan will be
activated.
The display for the current fan speed alternates every 2 seconds with the
flashing LED4.
LEDs1-3 flash
Flashing of most
recently active fan
speed when supply
air fan is switched
off
(Display of LED1-3
as example)
Frost protection
mode
From an outside air temperature of -4°C, the frost protection function is
automatically activated.
In frost protection operating mode, the ratio between the supply air and
extract air volume flow is automatically adjusted depending on the
outside air temperature, and the unit is shut down if the outside air
temperature is lower than -15°C. A check is made regularly as to whether
the temperature conditions in regard of frost protection have changed,
and the respective operating mode (requiring frost protection) is
activated automatically according to the result of that check.
After the unit is switched off, a flashing in those LEDs (by touching the
(+) or (-) key) which denoted the most recently active fan speed will be
signalled. The fan speed cannot be changed and is signalled with the
flashing of Fault LED
NOTE
Changing from a higher to a lower fan speed may not be possible
depending on the currently active frost protection routine.
The shutters are closed or opened automatically depending on the
currently active frost protection routine.
Fault LED flashes
Indication of
locked modes
If an inaccessible operating mode is selected, it will be signalled by the
flashing of Fault LED.
These operating modes are the locked standby, locked supply and
extract air mode and complete switch-off due to frost protection.

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Options for ventilation operation
The ComfoAir 70 can also be equipped with optional accessories for convenient operation and demand-controlled
ventilation mode.
NOTE
Ventilation operation by means of optional accessories requires the installation and configuration of those accessory
components.
External control panel
The Zehnder ComfoLED external control panel offers the possibility to operate the ventilation unit at a distance from the
integrated control unit. The operating and display elements of the external control panel correspond to those on the internal
control panel installed on the unit. If an external control panel is installed, the internal control panel supplied as standard
remains fully functional.
Operation via networking
3.2.2.1 Operation via radio module
Ventilation units in a ventilation zone can be easily networked with each other using radio modules. The function of the
ventilation units is synchronised. The settings are still made on the internal or external control panels.
Mixing systems with ComfoSpot 50 series ventilation units in a common ventilation zone are possible.
3.2.2.2 Operation via the connection hub and Zehnder Connect App
Using the connection hub and Zehnder Connect App, ventilation units with a radio module in a residential unit can be
conveniently operated via a mobile device. This allows complex networks to be set up. The central point of these networks
is the Zehnder connection hub. It serves as an interface between the ventilation units, the mobile end devices (app) and,
if available, a WLAN network with Internet connection for operating the units while away.
Mixed systems with ComfoSpot 50 series ventilation units in a common residential unit are possible.
Automatic operation via sensor module
The application of the Automatic function follows the logic of a demand-controlled system for optimizing the indoor air
quality. Consequently, an optimized response is achieved, and mildew formation is prevented, which ultimately also leads
to an increase in energy savings. The ventilation unit of the ComfoAir 70 series with a sensor module is classified in energy
efficiency class A.
NOTE
The automatic operating mode switches to frost protection operating mode if frost protection criteria are met.
3.2.3.1 Functional principle of HUMIDITY sensor
NOTE
The HUMIDITY sensor module is primarily supposed to be installed in units for the ventilation of rooms with an increased
occurrence of humidity.
The HUMIDITY sensor module is equipped with a combined humidity and temperature sensor and calculates the relative
humidity. In the evaluation of the current sensor signal for the setpoint selection, the fans are regulated in accordance with
the characteristic curve in diagram 1. Since the dehumidification performance decreases the smaller the temperature
Icon Description Explanation
LED filter
maintenance
flashes
Indication Filter
maintenance
The filters are monitored based on running time. 90 days are preset by
default.
After the filter runtime has elapsed, notification in regard of a filter
maintenance is signalled by the filter maintenance LED flashing.
Simultaneously touching the (+) and (-) keys for 3 seconds allows you to
acknowledge the indication of the filter maintenance and to reset the filter
runtime.
Fault LED lights up
Error code LED1-4
Signalling of error
code fault
message
If an error occurs, this is signalled by the fault LED.
Faults that can be diagnosed by the unit are symbolized by LED1-4 using
an error code.
Simultaneously touching the (+) and (-) keys for 3 seconds allows you to
delete the indication of the fault notification.

11
difference between indoor and outdoor air, at a difference of T < 5 K the air volume is reduced to 20 m³/h. When the
Bathroom function operating mode is active, the unit will be operated with the highest fan speed if the relative humidity
amounts to 80% or more.
Diagram 1: Factory setting characteristic curve for Automatic operating mode with humidity control
3.2.3.2 Functional principle of CO
2
/ VOC sensor
NOTE
The CO
2
sensor module and the VOC sensor module are each combined with a humidity/temperature sensor.
The CO
2
sensor module and the VOC sensor module both offer the option to evaluate relative air humidity as well as the
air quality for controlling the ventilation unit. The VOC sensor module detects volatile organic compounds (VOC) and the
CO
2
sensor module, as NDIR sensor (nondispersive infrared sensor), detects carbon dioxide (CO
2
). Volatile organic
compounds correlate with the CO
2
concentration in living spaces. In the evaluation of the current sensor signal for the
setpoint selection, the fans are regulated in accordance with the characteristic curve in diagram 2.
Diagram 2: Factory setting characteristic curve for Automatic operating mode with CO
2
/ VOC control
NOTE
The CO
2
and VOC sensor modules combined with a humidity/temperature sensor can be deactivated separately if
needed, in accordance with the humidity or air quality control. The HUMIDITY sensor technology is primarily supposed
to be installed in units for the ventilation of rooms with an increased occurrence of humidity. However, if both sensor
functions are configured as active, the control characteristic of the higher sensor signal becomes effective.
The required hardware settings on the control system are only allowed to be made by qualified personnel.
Maintenance by the user
Maintenance work on the ventilation unit is limited to filter replacement and external cleaning as required.
NOTE
If the maintenance work is not carried out regularly, this will affect the functionality of the ventilation unit in the long run,
in particular in the case of a failure to perform filter maintenance.
Filter maintenance
The ventilation unit has a runtime-controlled filter monitoring system with visual indication via the filter maintenance LED.
The filter monitoring period is 90 days as standard but can be adjusted to a period of between 30 and 180 days by the
customer service department using a programming module.
NOTE
If the air is heavily polluted (e.g. with road traffic, industrial use, in rooms with increased dust levels), change the filters
every three months.
0
10
20
30
40
50
0 102030405060708090100
Volume flow [m³/h]
Rel. humidity [%]
Humidity control
0
10
20
30
40
50
400 600 800 1000 1200 1400 1600 1800 2000
Volume flow [m³/h]
Concentration CO2 [ppm]
CO2 / VOC control

12
3.3.1.1 Replacing the air filter
NOTE
The ventilation unit must not be operated without filters. During filter maintenance, the unit needs to be transferred to
the Standby operating mode.
The ventilation unit is equipped with two air filters of filter class ISO Coarse 70% as standard. Retrofitting with filters of filter
class ISO ePM10 80% is possible, preferably the higher quality ePM10 filter is inserted into the lower filter compartment
as an outdoor air filter. No tools are needed to change the air filter. Proceed as follows with the relevant filter maintenance
LED signal:
1. Put the unit into the Standby operating mode.
2. Remove the upper design cover by pulling it out of the guides in an upwards direction.
3. Use your finger to go into the recess between the filter cover made of cellular rubber and the EPP housing, and pull
the filter cover out.
4. Gripping the pulling tabs, pull the filter carefully out of the filter compartment.
5. Using the directional arrow of the filter label pointing to the centre of the unit, insert the new filter into the filter
compartment. Make sure that the filter is not pushed into the housing with force.
Filter compartment for extract air filter ISO Coarse
Filter compartment for outdoor air filter ISO Coarse or
ISO ePM10

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6. Put the upper design cover onto the unit from above. Make sure that it engages, both in the guide for the lower
design cover as well as with the locking nipples, into the designated spring clips of the wall bracket.
7. Switch the unit back into the desired operating mode.
3.3.1.2 Resetting the filter maintenance display
The filter maintenance indicator must be reset after each air filter change in order to restart the filter maintenance cycle
monitoring. To do this, touch the (+) and (-) keys on the control panel simultaneously for three seconds. The flashing red
filter maintenance LED will go out.
NOTE
As part of filter maintenance for units with a second room connection, check any other air filters that may be present in
the ventilation system.
Unit maintenance
Maintenance of the unit is limited exclusively to the external surfaces of the ventilation unit and the operating surface of
the control panel, which should be wiped down from time to time using a soft, damp cloth – never just wipe dry.
WARNING
Risk due to electric shock
Disconnect the ventilation unit from the power supply before cleaning.
Make sure that no moisture can enter the inside of the housing during cleaning.
Never use a high-pressure cleaner, steam cleaner or steam jet.
NOTE
Never use flammable, acidic, corrosive or abrasive cleaning agents.
What should I do in case of a malfunction?
In the event of a fault message (indicated by the LED fault lighting up continuously), contact customer service.
Information about the type of your ComfoAir 70 can be found on the type label, which is located under the design cover of
the unit.
NOTE
As a reaction to a fault status, the fans are shut down and the shutters automatically closed.
As soon as there is a disconnection, the apartment will no longer be mechanically ventilated. This may result in moisture
and mould problems in the room that requires ventilation.

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4 Chapter for qualified personnel
Installation requirements
The following requirements must be assured for the correct installation:
Installation in accordance with the general and locally applicable safety and installation regulations from, among others,
the electric utility, and in accordance with the regulations stipulated in this manual.
Outside wall with final construction thickness of minimum 275 mm.
Sufficient space from objects and for maintenance work (at least 10 cm on extract air side, 20 cm on the supply air
side, 80 cm at the front, and 20 cm above the unit), with regard to the housing surfaces when installed.
Minimum distances on the facade side for outdoor air 10 cm, for exhaust air 20 cm; recommended suction opening for
the outdoor air with respect to the ground >1 m, however, at least unpolluted air in the suction area.
Electrical connection for stationary units for a working voltage range between 100–240 VAC / 50–60 Hz.
Packaging and handling
The ventilation unit and the facade finish are packed in a transport-safe box. Proceed with care when unpacking and
handling the ComfoAir 70.
NOTE
Do not damage or dispose of the packaging before final installation of the ventilation unit.
Checking the scope of delivery
If damages or incompleteness should be determined at the delivered product, please contact the supplier immediately.
Included in the scope of delivery are:
ComfoAir 70, including installation kit
Facade finish including installation set
Mounting template as imprint on the inside of the lid of the box
User manual
Product labels for energy-efficiency label
Installation
General installation requirements
The following requirements and precautions at the installation site must be taken into account:
WARNING
Observe accident prevention regulations
Observe the accident prevention regulations when setting up the installation site.
Secure the outside area against falling parts.
WARNING
Danger due to escaping gas or electric shock
Make sure that there are no supply lines (e.g. electricity, gas, water) in the area of the external wall opening.
Ensure that the external wall opening meets the static requirements on site.
WARNING
Risk due to electric shock
Observe the country-specific standards/regulations for compliance with the protection areas for installation in rooms
with a bathtub or shower with regard to the IP20 degree of protection applicable to the ventilation unit.
CAUTION
Risk of injury due to falling design cover
The ComfoAir 70 is intended exclusively for installation in an external wall, whereby the housing must be positioned
vertically on the inside of the wall with the exhaust and supply air grilles at the top.
NOTE
The electronics/control unit can be damaged by static charge; which is why you must always take measures to prevent
electrostatic discharge when handling the control unit (e.g. by wearing an anti-static armband).

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Installation preparations
4.2.2.1 Preparations for installing the wall mounting pipe
Prior to installing the ventilation unit, an appropriate wall mounting pipe must already be installed in the outside wall at the
designated installation location. It must be adjusted flush with the dimensions of the final wall structure.
The square wall mounting pipe, intended in particular for new buildings, should be integrated in the outside wall construction
in the course of constructing the outside wall. The round wall mounting pipe is to be inserted after drilling a core hole (
270 mm) into the drill hole of the outside wall.
NOTE
Installation of the ComfoAir 70 requires the use of the round or square wall mounting pipe.
Observe the respective enclosed instructions on professional installation when installing the wall mounting pipe.
Use the mounting template in order to transfer all centrings for the holes onto the inner wall surface.
4.2.2.2 Preparations for installing electrical connections
The mains cable for the power supply and, if necessary, the control cable for connecting an optional external control panel
must be inserted into the unit through the cut-out in the wall bracket. The cable ends should protrude approx. 10 cm from
the wall surface in the area of the cable entry point in order to establish secure clamp connections with the cables on the
unit side.
NOTE
For the power supply, a mains cable (recommended type NYM-J 3x1.5) for stationary units with disconnection with a
contact opening width corresponding to the conditions of overvoltage category III for full disconnection must be provided
on site.
For the connection of an optional, external control panel, a control cable (recommended type J-Y(ST)Y 2x2x0.6) must
be laid on site between the external control panel and the ventilation unit.
Connecting ventilation tubes
The ventilation unit has four ventilation tube connection options in the upper EPP housing section for direct ventilation of
a room network.
These openings for connecting ventilation tubes must be made on site if necessary when the unit is installed, since the
ComfoAir 70 is supplied as a single room ventilation unit in the standard version.
NOTE
The ventilation tubes can be installed either on the side and/or on the back of the unit.
It is not permissible to connect one ventilation tube of the same type to the side and one to the back of the connector.
Components and accessories from the Zehnder product portfolio are recommended as ventilation tube material.
The ventilation tubes in an adjoining room connection have an effect on the volume flow balance of the ventilation unit.
The customer service team is to use the programming module to balance the system according to the system
characteristics curve.
4.2.3.1 Back connection of the ventilation tube
To connect the ventilation tube to the back wall of the unit, remove the end caps from the upper EPP housing section.
Close the respective side connector with the removed end cap.

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Graphics as an example for the connection of a back supply air ventilation tube
NOTE
When using the joining piece (“Convertor 90 to flat 51, bend 90°”), the connecting 51 flat duct must be routed in a
downward direction, and then only using a 90° angle (“Bend flat 51 H”) to the left or to the right. The reason for this is
the fixing point of the wall bracket, where the fixing point is not allowed to be located in the vicinity of the flat duct.
When mounting the unit on drywall or on an in-wall installation, use shorter screws or dowels with a maximum length of
35 mm.
Install the ventilation tubes air-tight at the designated connectors. For this purpose, use the recommended self-adhesive
sealing tape (accessory item), which must be stuck on the outside over the entire circumference of the connector.
For correct installation, the appropriate joining piece must protrude so far out of the wall so that the connector with the
attached sealing tape is inserted in the EPP housing section.
4.2.3.2 Side connection of the ventilation tube
If the ventilation tube is connected at the side, the pre-perforated external wall grille of the wall bracket must be removed.
To do this, cut the two web connections of the external wall grille with the wall bracket by rotating the grille around the axis
of the webs until the predetermined breaking point breaks.
Graphics as an example for the connection of a side supply air ventilation tube
CAUTION
Injury at sharp-edged predetermined breaking point of the web connections
After cutting out the external wall grille, carefully deburr the remaining material of the two web connections at the wall
bracket cut-out.
The corresponding connection piece must be pushed into the groove of the opening of the EPP housing section until the
sealing tape (for joining piece “Convertor 90/75 to flat 51”) or the lip seal (for joining piece “Comfotube 90 / DN100”) is
engaged.

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NOTE
The side connection of the ventilation tubes must be designed so that it can be dismantled for maintenance / repairs,
i.e. it must be possible to pull the connection piece out of the cut-out in the upper EPP housing section.
Installing the ventilation unit
DANGER
Fatal voltages
Disconnect all poles of the mains cable intended for connection to the ventilation unit from the power supply before
carrying out installation and maintenance work.
Proceed as follows for the installation of the unit:
NOTE
Remove the transport lock attached to protect the lid mechanism. Follow the instructions on the yellow sticker located
on the EPP housing unit exactly.
1. Pull the upper outer cover upwards and out of the bracket and undo the two screws to remove the lower design cover.
Be sure to hold the lower design cover while doing so.
2. Pull the ribbon cable on the inner side of the design cover, gripping the red plug, carefully off the board of the internal
control panel.

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3. Remove the wall bracket from the EPP housing so that the unit is now available with no housing components.
4. The length of the EPP pipe housing must correspond to the length of the wall mounting pipe installed in final wall
thickness +5 mm. For this purpose, even if an EPP housing extension is required, the EPP pipe housing of the unit
must be shortened.
NOTE
The cut must be performed in the shortening area all around, perpendicular to the axis of the EPP pipe housing.
5. Drill the four holes in accordance with the mounting template for fixing the wall bracket, and insert the supplied, or,
depending on the wall construction, relevant mounting material (wall plugs) into the holes.
NOTE
Use the mounting template on the lid of the box or the wall bracket as an aid for marking the required holes for
mounting the wall bracket.
6. Screw the wall bracket to the inner wall and take care to ensure that the mains supply line and, if present, the cable for
the external control panel, are located in the area of the cable entry point.
7. Now carry out the electrical installation steps described in chapter “4.4 Electrical connections”.
WARNING
The activities described in this chapter may only be carried out by skilled personnel with the following
qualifications:
Training on the installation and commissioning of electrical units.
Training on electrical hazards and local safety regulations.
Knowledge of the relevant standards and guidelines.
NOTE
Optional accessories, such as sensor modules, wireless or wired operating modules, must be installed before the
power supply connection. For this purpose, use the installation instructions enclosed with the respective accessories.
8. Fasten the lower design cover using the left-hand screw. The lower design cover can now be pivoted. Connect the
ribbon cable to the control panel as shown.