Zehnder Rittling ComfoAir 155 WM User manual

ComfoA r 155 WM
Mechanical Ventilation with eat Recovery
Installat on Instruct ons
CA155WM-GB

2
Page
1.0 General Descr pt on / Phys cal Spec f cat on ........................... 3 - 4
2.0 Installat on Instruct ons .............................................................. 4
General Preparation ...................................................................... 4
Configuration ................................................................................. 5
Mounting ....................................................................................... 6
Access for Maintenance ............................................................... 7
Condensate Drain ......................................................................... 7
Ducting Guidelines ....................................................................... 8
Electrical ....................................................................................... 9
Wiring the Unit .............................................................................. 10
Connecting to the BMS ................................................................. 11
3.0 On-S te Comm ss on ng ............................................................. 14
4.0 Guarantee ..................................................................................... 20
Contents

3
1.0 General Descr pt on / Phys cal Spec f cat on
1.1 Overv ew
1.1.1 The ComfoAir 155 WM is a ventilation system designed to provide improved indoor air quality in dwellings.
As a whole house system, the unit continuously extracts air from the non-habitable rooms and supplies fresh,
filtered air to habitable rooms. eat that is recovered from the air drawn from the bathrooms and kitchen is
passed through a heat exchanger and the heat that is recovered is transferred, to temper the supply air in
habitable rooms to provide a comfortable indoor environment.
1.1.2 A boost speed facility is provided to increase the ventilation rate, e.g. when cooking or showering, providing a
comfortable indoor environment. A two speed operation can be done via the Switch-Live (SL), a ZGS2 SL boost
switch or a ZGRC1 boost and alert controller can be used to provide this operation. A three speed operation can
be done via the ZGS1, or combining the Switch-Live with a ZGS2 SL switch for the AUX speed.
(See Sec ion 2.8.5 Elec rical).
1.1.3 This product features on the PCDB as a high efficiency version and part of the process requires the Installation
Checklist for MV R products to be completed and submitted to building control, available at
www.ncm-pcdb.org.uk along with all other relevant paperwork.
1.1.4 Ancillary Items Required
ComfoAir 155 W
• 125mm Ducting (rectangular ducting can be used, where appropriate)
• ZGS2 ardwired switch providing switching between low and high (option)
• ZGRC1 ardwired boost and system status controller, switching between low and high (option)
• ZGS1 ardwired switch providing switching between low, AUX and high (option)
1.1.5 Packaging includes:-
1 x eat Recovery Unit
1 x Wall Fixing Bracket (ComfoAir 155 WM)
Quick User / Quick Installer Guide
1.1.6 Warning: This appliance can be used by children aged from 8 years and above and persons
with reduced physical, sensory or mental capabilities or lack of experience and knowledge if
they have been given supervision or instruction concerning use of the appliance in a safe
way and understand the hazards involved. Children shall not play with the appliance.
Cleaning and user maintenance shall not be made by children without supervision.
1.1.7 Where an open-flued oil or gas-fuelled appliance is installed, precautions must be taken to
avoid a back-flow of gases into the room.
1.1.8 The design, material specification and installation must only be carried out by "competent
persons". Electrical installation must be carried out by a qualified Electrician.
1.1.9 'If the supply cord is damaged, it must be replaced by a special cord / assembly available
from the manufacturer or its service agent. The replacement must be carried out by a
qualified electrician in accordance with IEEE or local regulations'.
1.1.10 Observe appropriate safety precautions if working on steps or ladders. Wear eye protection
when breaking out walls or window materials.
1.1.11 To disassemble the unit, disconnect from mains supply and use a screwdriver to segregate
the electronic components and motors from the plastic housing. Dispose items in
accordance with WEEE.

4
1.1.12 WEEE Statement
This product may not be treated as household waste. Instead it should be handed to
an appropriate collection point for the recycling of electrical and electronic equipment.
For more detailed information about the recycling of this product, please
contact your local council office or your household waste disposal service.
1.2 Physical Specifications
ComfoAir 155 W
2.0 Installation Instructions
2.1 General Preparation
2.1.1 The ComfoAir 155 WM unit is supplied with 4 x 125mm Ø spigots.
• 125mm ducting with connectors can be used (see Ancillary Section page 3) to provide performance levels
required for compliance with local Building Regulations.
2.1.2 Installation of the unit should be in accordance with the current editions of Building Regulations, N BC
Compliance Guide and BS7671: IEE Wiring Regulations.
2.1.3 The design, material specification and installation must only be carried out by "competent persons". Electrical
installation must be carried out by a qualified Electrician.
2.1.4 I PORTANT NOTE: Gases from fuel-burning equipment must not be
drawn into any living areas. If any room, where air is extracted, contains
a fuel-burning appliance such as a central heating boiler, then either of
the following should be undertaken:
• The flue must be of the room sealed or balanced flue type or;
• Allowance must be made for an adequate supply of air into the room.
546
125
50
594
298
644
Front View Side View

5
2.2 Pos t on ng
2.2.1 The ComfoAir 155 WM unit must be installed vertically and can be either wall or floor mounted to enable
effective condensate drainage in either a kitchen/service cupboard or secured to a vertical structure in the loft
space. If located within a cold space, it is recommended that the bottom of the unit is insulated to prevent
freezing around the condensate connection. Duct spigots must be upright at top of unit.
2.2.2 It is not advisable to install the unit directly above a bedroom or living room ceiling, or in an area that is part of a
living area or bedroom.
2.2.3 Consideration must be given to allow for adequate access for servicing, maintenance and any fault diagnostics
(See Sec ion 2.5 Access for Main enance).
2.2.4 The unit can be configured for right and left hand installation at a touch of a button by following the steps within
the Commissioning Wizard (See Sec ion 3.1.4 Commissioning Wizard) and does not require any internal
changes. (See Figures overleaf for duc ing configura ion).
2.3 Conf gurat on
Note: To change the handing of the unit, follow the simple steps within the Commissioning Wizard (See Sec ion
3.0). Automatically done for you via software.
ComfoA r 155 WM
Left Hand
EXTRACT
SUPPLY
EXHAUST
INTAKE
Right Hand (factory setting)
INTAKE
EXHAUST
SUPPLY
EXTRACT

6
2.4 Mount ng
2.4.1 The ComfoAir 155 WM unit is supplied with one wall fixing bracket. The bracket is a long strip and has two
adjustable fixing points located at the end of the bracket. Screws and fixings not supplied.
2.4.2 Proceed to align the wall bracket taking into account the available wall space to mount the unit, ensuring that the
wall can support 20kg.
2.4.3 Use a spirit level to assist mounting and levelling the bracket. Securely fix bracket to wall using suitable fixings.
2.4.4 The unit fixes to the wall bracket by slotting the bracket attached to the back of the unit and hooking into place.
Note:
• Fixing Bracket height will be critical in kitchen
cupboard.
• There should be no movement once correctly
located and the filters should be accessible by
easily removing the panels on the front of the unit.
(See Section 4.1.8 within the User / Homeowner Guide).
Fixing Bracket

7
2.5 Access for Ma ntenance
Footprint of ComfoAir 155 W
2.6 Condensate Dra n
2.6.1 It is important that any condensate MUST be drained away.
• The ComfoAir 155 WM unit is provided with a condensate drain located at the base of the unit
underneath (See Figures 1-3).
The drain plug allows a condensate drain hose (21.5mm diameter) to be push connected and solvent
welded/sealed. Please ensure a water tight seal is achieved.
2.6.2 The drain must have a 5º fall and can either be chased into the wall or run downwards from the unit into the
nearest waste water network. Ensure that steps are taken to minimise the risk of mechanical damage to the
drainage pipe work.
I PORTANT NOTE: The condensate drain must incorporate a waterless
trap or U bend to create an air block and avoid leakage of smells back
into the unit. If the unit is installed within a loft space, please ensure
that the condensate drain is insulated to prevent against freezing.
2.6.3 In some instances, a condensate connecting point will already be provided as part of the building design.
The position of this point, relative to where the unit is to be installed should be checked for any connection
misalignment and any necessary adjustment made before proceeding any further.
500mm
Side ViewTopView
500 mm
250 mm

8
ComfoA r 155 WM
2.7 Duct ng Gu del nes
2.7.1 Please refer to design drawings for proposed ducting layout.
2.7.2 Four spigots are provided for connection of the ducting;
• ComfoAir 155 WM - 125mm nominal diameter
Ductwork should be securely connected to spigots. Failure to do this will cause unnecessary air leakage and
impair performance. Ducting must be connected to all four spigots according to right or left hand configuration
(See Section 2.3 for Configuration). It is recommended that a minimum distance of 200mm is maintained
between the ComfoAir 155 WM and any ducting bends.
2.7.3 To prevent condensation, ensure that the intake and exhaust ductwork from the unit is insulated.
2.7.4 Where ducts are exposed in unheated areas, such as roof spaces, they must be insulated with at least 25mm of
insulation.
2.7.5 If applicable, Fire Dampers UST BE FITTED in accordance with Part B of the Building Regulations.
2.7.6 Rigid Ducting
• Install using the fewest number of fittings to minimise resistance to air flow.
• Where possible, final connection to grilles and unit should be made with a flexible connection.
• Mechanically fix ducts using metal jubilee clips and appropriate non-hardening sealant for air tightness.
WARNING: Do not use screws for connection and ensure jubilee clips
are not over tightened.
2.7.7 Flexible Ducting
• Ensure ducting lengths are kept to a minimum and ducting is pulled taut so that it is smooth and straight.
A maximum of 300mm should be used on each spigot.
• Mechanically fix ducts using metal jubilee clips and tape seal for air tightness.
W ARNING: Should be in accordance with local Building Regulations.
Figure 1 - Close up view
of condensate
Figure 2 - Front View Figure 3 - Side View
Min 5º fall

9
2.7.8 The intake fresh air should be directly from the outside.
• If drawn through a wall, an external grille should be fitted.
• If drawn through a roof, a recognised roof terminal should be fitted.
• Ensure that the free area opening of the grille/terminal is a minimum of 90% of the free area of the ducting
being used.
2.7.9 The exhaust air must exit to the outside through a wall or roof and must be protected by a wall grille or
recognised roof terminal.
• Roof terminal to have a minimum equivalent free area of 10,000mm2.
2.7.10 Intake and exhaust pipes should be installed at least 1m apart to avoid the cross contamination of airflows.
2.8 Electrical
2.8.1 WARNING: The appliance MUST be earthed.
All wiring must conform to IEE or local Wiring Regulations (minimum allowance on switch-live is 12V).
2.8.2 The installation must be carried out by a qualified Electrician.
2.8.3 All units are suitable for a 230V ~ 50 z single phase supply fused at 3A.
2.8.4 A triple-pole switch having a minimum contact separation of 3.0mm must be used to provide isolation for
the unit.
2.8.5 The recommended switches for use with this product are the Zehnder;
ZGS2 - Optional 2-position hardwired switch
ZGRC1 - Optional boost + system status hardwired remote switch
ZGS1 - Optional 3-position hardwired switch
(See Section 2.9 for wiring diagrams)
Note: The unit may also be wired to a Building anagement System (B S)
(See Section 2.9.5 for wiring details).
2.8.6 The controllers must not be mounted in a bathroom or above/closer than 1 metre to a cooker where it could be
affected by excessive heat or moisture.
2.8.7 The ComfoAir unit is supplied with a pre-wired mains flexible cord - PVC sheathed, 5-core green/yellow, grey,
brown, black & blue. Size 0.75mm.
2.8.8 'If the supply cord is damaged, it must be replaced by a special cord/assembly available from the
manufacturer or its service agent. The replacement must be carried out by a qualified Electrician in
accordance with IEE or local regulations'.
ZGS2 ZGS1
Controller Switch Type Speeds
ZGS2 2 - position rocker Low (I) igh (II)
ZGRC1 Single push button Low (I) igh (II)
ZGS1 3 - position rocker Low (centre), AUX (I), igh (II)
ZGRC1

10
2.9 Wiring Diagrams Key: Earth = Green / Yellow
Neutral = Blue
Brown = Permanent Live
Black = AUX speed
Grey = igh speed
2.9.1 Two speed control via a light switch
2.9.2 Two speed control via ZGS2 switch
2.9.3 Three speed control via ZGS1 switch
2.9.4 Three speed control via a light switch for trickle & boost speeds and an AUX speed activation via a ZGS2 switch
Flying lead from CA155
Flying lead from CA155
Flying lead from CA155Flying lead from CA155

11
2.9.5 Wiring Enhanced Control Options via the Building anagement
System (B S)
2.9.6 To wire into to the BMS connector within the ComfoAir 155 WM, first remove the electrical wiring cover as
per Fig. 4 below then locate the BMS connector on the PCB (maintain a minimum separation distance of 35mm
between the mains power and controller cables).
Supply cord
BMS
Connector
Pre-wired
supply cord
connector
DO NOT
DISCONNECT
ComfoAir 155 W
Figure 4 - Top View
Cable grommet
for BMS
connection
Pre-wired
supply cord
not shown
Warning: Ensure that you use the cable grommet provided when
connecting to the B S to protect against potential water ingress. Take
care that the gasket seal underneath the PCB cover is not disturbed.

12
2.9.7 Using suitably sized cabling, the BMS terminal block can be removed for easier wiring.
• Pins 1 - 2 allows a remote switch to be used for a boost switch (Note: NOT FOR MAINS WIRING).
• Pins 2 - 3 to be used exclusively with a ZGRC1 controller.
• Pins 4, 5 & 6 allows for remote fault indication. Relay will be energised upon detection of a fault.
Upon completion of wiring, carefully push fit BMS terminal block back onto PCB.
Figure 5 - Close-up of PCB with BMS connection points
Pin Function Connection to External Circuit
1 Boost For additional sensors to igh
2 Ground 0V
3 Remote Connecting to a ZGRC1 controller (option)
4 N/C Volt - Free normally closed contact
5 N/O Volt - Free normally open contact
6 Common Relay common
Figure 6 - ZGRC1 Controller Figure 7 - BMS iring Diagram
123456
12 6
543
N/C N/O COM
ELECTRICAL CONNECTION / TERMINAL DIAGRAM
BOOST GND REM
ZGRC1
REMOTE CONTROLLER
(ZGRC1 - Option)
VOLT FREE CONTACTS
GIVING FAULT
IDENTIFICATION
}
REM
GND
BATHROOM SW.
(Volt free contact)
NOT RATED FOR
MAINS SWITCHING
BMS CONNECTOR
RL1 - RELAY
Note: Only one ZGRC1 boost and status controller can be installed with the ComfoAir 155 WM. Additional boost
actuation should be via either 'switch-live' or standard hardwired 2-position switches. A separate AUX switch
cannot be installed when using a ZGRC1 boost and status controller.
1 2 6
5
4
3
N/C N/O
COM
BOOST GND
REM
ComfoAir Unit
BMS Connector
2 core cable, 0.5mm Max.
(up to 15 metres)
ComfoAir 155 WM
BMS Connector

2.9.8 When wiring has been completed apply cable clamp and retain the cable sheath securely in place by tightening
the cable clamp down with screw fixings.
2.9.9 Refit electrical cover, taking care gasket seal underneath is seated correctly and cable is not trapped.
13
12345
12345
Pre-wired
supply cord
not shown
Figure 8 - Securing BMS iring (Cable not supplied)
Pre-wired
supply cord
not shown
Figure 9 - Electrical Cover Attached (Cable not supplied)

14
3.0 On-Site Commissioning
3.1.1 This section covers set-up, configuration of the unit for installation and altering pre-set factory settings. For
instructions on how to operate the LCD display user menu, maintenance options and indicator warning
information, please refer to the User / omeowner Guide.
3.1.2 Once the wiring connections have been checked, switch the mains supply on and check that the system is
operating correctly. Lift cover of commissioning wizard located at the top of the unit. Upon connection of
electrical supply, the commissioning wizard will automatically turn on (See Section 3.1.4).
3.1.3 Overview of Integral LCD Display
P ORT CONF I G :
<RH>
Example 1: Function selection screen
Top line - function / statement.
Bottom line - flashing cursor indicating next
action to be reviewed/changed.
PORT CONF I G :
<RH> >dwf> ckab
Example 2: Re-confirmation screen
Top line - function / statement.
Bottom line - three selectable functions
always come into screen with fwd flashing.
Option to move forward towards completion or
back to re-set function.
SETUP COMP LE TE
>i txe> ckab
Example 3: No editable variable in middle only ever seen as last step in the wizard
Top line - function / statement.
Bottom line - two selectable functions
only found at the end of the wizard.
Selection of exit will confirm all wizard
configuration settings.
Frost
Protection
LED
Service/Fault
LED
Summer
ByPass
LED
Control Information Panel
Control
Button
# eaning
A Control Information Panel
B Control Button
C Summer ByPass LED
D Frost Protection LED
E Service/Fault LED
A
C
B
DE
Below are examples/explanations of what you would see through the
Commissioning Wizard.

3.1.4 Commissioning Wizard
To progress through the commissioning wizard, rotate the controls central button to required configuration and
press the button to select (at each section the text will flash until it has been selected, whereby it will then go
solid). You can move backwards and forwards throughout the process until all settings are correct.
How to navigate through the Commissioning Wizard
1. Lift cover on the front of the unit.
2. When first turning the power onto the unit, the 'Setup Wizard' prompt will be shown.
3. Press the 'Control Button' to start the commissioning wizard.
4. Refer to design drawings for setting up the required configuration.
5. Go through the steps shown below.
6. Identify the desired setting for each point and press the button to select.
7. Rotate button to choose FWD to move to next section or BACK to return to previous set-up.
8. Press button to select FWD / BACK.
9. Complete commissioning at the last step by selecting EXIT.
After each section rotate button and choose FWD to move to next section or BACK to return to set-up.
Press button to select choice.
The steps of the wizard are as follows:
15
PORT CONF I G :
<RH>
EXTRACT H I GH
<66%>
SUPPL Y H I GH
<66%>
EXTRACT LOW
<33%>
SUPPL Y LOW
<33%>
Port Configuration Set-up
Rotate button to choose either R (Right and
Configuration) or L (Left and Configuration)
High Set-up
Factory airflow set at 66%, rotate button to required
airflow %
Supply High Set-up
Factory airflow set at 66%, rotate button to required
airflow %
Low Set-up
Factory airflow set at 33%, rotate button to required
airflow %
Supply Low Set-up
Factory airflow set at 33%, rotate button to required
airflow %
EXTRACT AUX
<50%>
SUPPL Y AUX
<50%>
AUX Extract Speed Set-up
Factory airflow set at 50%, variable between
15%-100%, rotate button to required airflow %
AUX Supply Speed Set-up
Factory airflow set at 50%, variable between
15%-100%, rotate button to required airflow %
Step 1
Step 2
TIMERSMART
<ON >
SETUP C OMPLETE
<ba ck ex i t >
Timer Set-up
Rotate button to choose either ON or OFF
(Default setting: ON)
Commissioning Set-up Wizard Completion
Rotate button to choose either EXIT to complete
commissioning or BACK to return to set-up
HUM I D I SMAR T
<ON >
Humidity Set-up
Rotate button to choose either ON or OFF
(Default setting: ON)
Step 3
Step 4
Step 5
Step 6
Step 7
Step 8
Step 9
Step 10

16
3.1.5 Wizard enu Structure
Extract High
Rotate button to choose either RH (Right Hand) or LH (Left Hand) Configuration
Factory airflow set at 66%, rotate button to required airflow %
Port Configuration
Supply High Factory airflow set at 66%, rotate button to required airflow %
Extract Low Factory airflow set at 33%, rotate button to required airflow %
Supply Low Factory airflow set at 33%, rotate button to required airflow %
Extract AUX Factory set at 50%, variable option 15%-100%, rotate button to required airflow %
Supply AUX Factory set at 50%, variable option 15%-100%, rotate button to required airflow %
Smart Humidity Rotate button to choose either ON or OFF (Default setting: ON)
Smart Timer Rotate button to choose either ON or OFF (Default setting: ON)
Setup Complete Rotate button to EXIT and press button to select
Installer Settings
3.1.6 Valve Set-up
• Set the fan speed approximately to achieve the desired extract high flow rate.
• Close all windows and doors, including the rooms in which measurements are being carried out.
• The index terminal (the one furthest away) should be set to fully open.
• All other terminals are adjusted to achieve the required flow rate.
• If the index terminal has to be closed to achieve the correct flow rates, then reduce the fan speed and
balance the terminals.
• Switch the unit to low speed to achieve the desired extract low flow rate.
It should not be necessary to adjust the extract valves further.
• Repeat tests for supply air valves.

17
3.1.7 Once the unit is commissioned check that the system is operating correctly by turning the hardwired switch to
the differing settings, i.e. the ZGS2 switch or ZGRC1 Controller will activate the unit between low and high
speed settings, alternatively the ZGS1 will activate the unit between low, AUX and high speed settings.
• Performance levels can be verified at both extract and supply air valves using an appropriate method
such as a rotating vane anemometer and air cone kit.
• Refer to performance graph for ComfoAir 155 WM airflow characteristics (See Section 3.1.8).
Note: All settings are stored within the ComfoAir 155 W unit’s memory and should NOT be lost in the
event of a power failure. When power is restored, the unit should revert to normal running with all
settings unchanged. Likewise, reminder indicators are NOT reset.
3.1.8 Performance Graph - Airflow Characteristics
SETUP MENU ><
pas sword ent r y
PASSWORD
XXXX
3.1.9 To Re-activate Commissioning Set-up Wizard
In the event that the unit needs to be adjusted once the commissioning wizard has been completed;
• Press the control button to activate the unit.
• Rotate button until the screen displays "Setup Menu".
• Press button to select.
• Enter Password "1010" by rotating the button to the respective
number and press to select (this has to be completed for each
number prior to continuing).
• Once commissioning setup has been re-activated, rotate button to
desired setup change and follow (see Recommissioning Menu
Structure 3.1.10), press the button to select.
• Current set-up will be shown, change to new requirement & press
button to confirm.
• Rotate button 'right' to move to next section or 'left' to return to
previous set-up.
• Complete all sections requiring changes.
• Upon completion, to save and exit, rotate button to "Exit", press
button to confirm.

18
3.1.10 Recommissioning enu Structure
Port Configuration
Input password 1010 to proceed into Setup enu screens
Rotate button to choose either RH (Right Hand) or LH (Left Hand) Configuration
Password
Extract High Wizard airflow setting will be shown . . . rotate button to required airflow %
Supply High Wizard airflow setting will be shown . . . rotate button to required airflow %
Extract Low Wizard airflow setting will be shown . . . rotate button to required airflow %
Supply Low Wizard airflow setting will be shown . . . rotate button to required airflow %
Wizard airflow setting will be shown . . . rotate button to required airflow %
Wizard airflow setting will be shown . . . rotate button to required airflow %
Humidismart Rotate button to choose either ON or OFF (Default setting: ON)
Timersmart Rotate button to choose either ON or OFF (Default setting: ON)
Setup enu
Service enu
User enu
Recommissioning
V
V
See Homeowner Guide
See Homeowner Guide
Comfort Temp Rotate button choose between 21ºC - 28ºC (Default setting: 22ºC)
EXIT Rotate button to EXIT and press button to select
Extract AUX
variable option 15% - 100%
Supply AUX
variable option 15% - 100%

19
3.1.11 To odify Summer ByPass Activation Temperature
When the internal and external temperature conditions are met the unit will try to maintain an indoor comfort
temperature by operating the summer bypass valve. This can be adjusted as follows:
• Press the control button to activate the unit.
• Rotate button until the screen displays "Setup Menu".
• Press button to select.
• Enter Password "1010" by rotating the button to the respective
number and press to select (this has to be completed for each
number prior to continuing).
• Rotate button to “Comfort Temp” option and press to select - the
current setting status will flash.
• Rotate to desired outcome (between 21°C - 28°C), press button to
select. (Default setting: 22ºC)
• Upon completion, to save and exit, rotate to “Exit”, press button to
confirm.
SETUP MENU ><
pas sword ent r y
PASSWORD
XXXX
MFORT TE
<22ºc >
O
CMP

4.0 The Guarantee Period
4.1 This Zehnder ComfoAir 155 WM has a 2 Year Guarantee as standard with the option to extend to a
6 Year, subject to registration. Terms and conditions apply.
4.1.1 This does not affect your statutory rights.
4.1.2 Full details available at www.zehnder.co.uk.
All information is believed correct at time of going to press. E&OE.
All goods are sold according to Zehnder’s Standard Conditions of Sale which are available on request.
All dimensions referred to are in millimetres unless otherwise stated.
Zehnder Group International Sales reserves the right to change specifications and prices without prior notice.
© Copyright Zehnder Group 2019
Zehnder Group UK Limited
Watchmoor Point, Camberley,
Surrey, GU15 3AD
Customer Services: [phone]
Technical Services: [phone]
Email: [e-mail]
Web: www.zehnder.co.uk
Issue 1 December 2019