Vent-Axia HR25H Assembly instructions

Lo-Carbon
HR25
Single Room Heat Recovery Unit
Installation and Wiring Instructions
Stock Ref. N°
372261A HR25
372262A HR25H
372263A HR25P
372264A HR25L
372265A HR25LH
372266A HR25LP
PLEASE READ INSTRUCTIONS IN CONJUNCTION WITH ILLUSTRATIONS.
PLEASE SAVE THESE INSTRUCTIONS

372268 -
2
1.0Introduction 3
2.0Site Requirements 4
3.0Installation 5
4.0Maintenance 13
5.0Short Parts List 14
Section Page
Contents

1.0 Introduction
3
372268 -
1.1 Description
1. The Vent-Axia HR25 range of products are
“through the wall”heat recovery ventilators for
use in areas such as bathrooms and WCs.
2. The units are fitted with a 24V DC motor and
are supplied with a Switch Mode Power Supply
(S.M.P.S.). On normal setting the power
consumption is 2 Watts.
A 5m cable is provided for fixed wiring of the
unit to the S.M.P.S.
3. The twin impeller and heat exchanger
arrangement simultaneously supplies and
extracts air while transferring heat from the
stale exhaust airflow to the fresh intake airflow.
This provides up to 84% heat recovery from the
stale extracted air.
4. The range of products is as follows:-
HR25
The HR25 is fitted with a pull cord switch which
provides a twin speed control function.
HR25H
The HR25H is fitted with an adjustable humidity
sensor which automatically switches between
its high and low settings depending on the
relative humidity in the room of installation.
HR25P
The HR25P has an Infra-Red sensor which
detects a person moving in the room, which
then activates the unit to switch to its higher
setting. This unit can operate under two different
modes, direct action and delayed action.
HR25L, HR25LH and HR25LP
These are extended versions of the above
models. They are designed for installations
where the wall thickness is between 311mm
and 425mm.
Fig. 1

Fig.2
Fig.3
2.0 Site Requirements
2.1 Information
1. The unit is designed for installation in
external walls with a thickness of up to 310mm.
For wall thicknesses above 310mm, the ‘L’
version of the appropriate model must be used
(see page 12 ). The ‘L’ models are suitable for wall
thicknesses up to 425mm.
2. The unit must be sited and connected by a
suitably competent person and be in
accordance with current U.K. Building
Regulations and I.E.E. Wiring Regulations (BS
7671).
3. The unit must be installed in conjunction with
the separate power supply supplied,
which is intended for permanent connection to
the mains electrical supply. The unit and the
power supply are intended for fixed
wiring installation.
4. The power supply requires free air
circulation for effective operation It must not be
recessed into the mounting surface or covered
with any form of insulation, which might be used in
a ceiling or roof void. The unit must be sited such
that the ambient temperature will not exceed 40°C.
please ensure that the air vents on the enclosure
are not blocked or covered up.
5. Wiring to the unit in the U.K. must be via
a switched fused spur.
6. The spur should have a minimum contact gap
of 3mm in all poles.
7. Ensure that the mains electrical supply is
compatible with the rating label attached to the
product.
8. The unit must be sited such that the ambient
temperature will not exceed 40°C.
9. Do not site the appliance in the vicinity of
excessive levels of airborne oil or grease. or
directly over a cooker.
10. If the unit is installed in a room containing a
fuel burning appliance, the installer must ensure
that air replacement is adequate for both
appliances.
11. The unit must not be installed at a level
below 500mm from the floor.
12. The internal grille surround must be sited at
least 125mm away from the room ceiling (Fig. 3).
and 300mm away from any adjacent vertical
surface.
13. The external cowl of the unit must be sited
at least 500mm away from any flue of gas or
solid fuel appliances. This is to avoid back flow
of gases entering the room.
14. All safety regulations and requirements
must be strictly followed to prevent hazards to
life and property both during and after
installation and during subsequent maintenance
or servicing.
15. Ensure the mains electrical supply is
switched off before commencing installation or
maintenance.
2.0 Site Requirements
50mm minimum
50mm minimum
50mm minimum

3.0 Installation
5
372268 -
3.1 Initial Preparation
The unit is designed for installation in a 152mm
(6”) core drilled hole.
All installation can be undertaken from inside
the building except for fixing of the external
bezel if required.
1. After considering the site requirements (see
previous section), select a suitable position for
the unit and power supply enclosure (5m
maximum between unit and power supply).
2. Remove the unit fixing template from the rear
of the instructions.
3. Mark the position of the four fixing holes and
the mounting hole.
4. Cut the mounting hole to a diameter of
152mm (6”) using a core drill. Ensure that there
is a slight fall on the hole, from inside to outside
(Fig. 4).
5. Drill and plug the four fixing holes.
Install the fixed cable runs using mini-trunking
or via concealed installation. A 3-core red, white
and black low voltage cable is supplied for
connections between the unit and the power
supply.
6. Using the template supplied mark the
position of the four fixing holes for the power
supply enclosure. Drill and plug the holes.
7. Ensure the cable to the unit extends
sufficiently from the mounting hole to enable
the required connections within the control
enclosure.
1°
Outside Inside
Fig. 4

Fig.6
Fig.7
HR25 / HR25L ONLY
Disconnect and make safe
White wire for High speed/Off
Fig.8
HR25 / HR25L ONLY
Disconnect and make safe
Red wire for Low speed/Off
Fig.9
3.0 Installation
3.2 Installing the Power Supply Unit
1. Remove the power supply unit assembly
from the carton. (Fig.6)
2. Remove the power supply unit packaging.
3. The mains input to the power supply unit
must be routed via the rear of a single gang
surface mounted back box (not supplied).
NOTE: Mains wiring must be kept separate
from the SELV wiring.
The mains connection is to the terminals
marked L & N (Fig.7)
4. Feed the 3-core cable through the rear of the
back box.
5. Mark the fixing hole positions in the back box
(not supplied) then Drill and plug the wall to
secure the power supply enclosure using the
fixing screws provided.
6. Connect the 5m cable supplied to the red,
white and black low voltage supply via the
terminal block. (Fig. 7)
NOTE: Red is positive high speed, white is
positive low speed and black is negative.
This polarity must be maintained at the unit
connections.
HR25/HR25L ONLY
The HR25/HR25L units are factory set to
opearate continuously at high or low speed
via a pull cord switch.
Two alternative settings can also be
achieved by disconnecting and making safe
the respective wires at the cable end of the
terminal block within the power supply
enclosure. The settings are as follows:-
High speed / Off – Disconnect White (Fig.8)
Low speed / Off – Disconnect Red (Fig.9)
N.B For all other models, refer to the
respective installation page.
L
~N
SELV Supply
N
+
-
24V
0V8V
+
RED
WHITE
BLACK
220-240V~50Hz
REF: 447249
0-24V D.C
RED
BLACK
WHITE
L
~N
SELV Supply
N
+
-
24V
0V8V
+
RED
WHITE
BLACK
220-240V~50Hz
REF: 447249
0-24V D.C
RED
BLACK
WHITE
L
~N
SELV Supply
N
+
-
24V
0V8V
+
RED
WHITE
BLACK
220-240V~50Hz
REF: 447249
0-24V D.C
RED
BLACK
WHITE
Power supply unit
Located here

3.0 Installation
7
372268 -
3.3 Installing the HR25
1. Remove the unit, bezel and fixing pack from
the carton.
2. Unclip the removable grille from the unit and
remove filter (Fig. 10).
3. Loosen the two securing screws and remove
the grille surround (Fig. 11).
4. Remove the divider board (Fig. 11).
5. Measure the total wall thickness. The outer of
the two rubber seals is adjustable and should
be set in a position that is 25mm in from the
outer face of the external wall (Fig. 12).
6. Secure the rubber seal to the unit using the
adhesive provided.
7. Locate the unit in the mounting hole, but do
not push it fully in.
8. Route the low voltage cable from the power
supply enclosure to the unit.
9. Pass the low voltage cable through the cable
entry grommet at the top of the unit
(Fig. 14).
10. Secure the unit to the wall using the four
fixing screws provided.
11. Remove the control cover by undoing the
two retaining screws (Fig. 14).
12. Strip the low voltage cable sheath back
40mm from the end and separate the three
individual wires.
13. Connect the wires to the terminal block.
Connect red to red, white to white and black to
black (Fig. 13 & 14).
14. Ensure that the low voltage cable is routed
through the divider slot (Fig. 14).
15. Reassemble in reverse order ensuring the
divider board seals against the heat exchanger.
16. A bezel is provided to neaten the
appearance of the outside wall around the unit.
If required this should be fixed in place using a
suitable silicone/mastic sealant.
Fig. 10
Fig. 11
Fig. 14
Fig. 13
Filter
Removable Grille
Divider Board
Heat
Exchanger
Grille Surround
Securing Screws
Pull Switch
Motor Wires
Control Cover
External Bezel
Control Cover
Cable Entry Grommet
Divider Slot
Low Voltage
Terminal Block Wiring
Label
White
Red
Red
Motor
Switch
From Power
Supply Enclosure
Black
White
Red
Black
Fig. 12
Outside
Wall
Rubber
Seal
25mm

3.0 Installation
8
372268 -
3.4 Installing the HR25H
1. Remove the unit, bezel and fixing pack from
the carton.
2. Unclip the removable grille from the unit and
remove filter (Fig. 20).
3. Loosen the two securing screws and remove
the grille surround (Fig. 21).
4. Remove the divider board (Fig. 21).
5. Measure the total wall thickness.
The outer of the two rubber seals is adjustable
and should be set in a position that is 25mm in
from the outer face of the external wall (Fig. 22).
6. Secure the rubber seal to the unit using the
adhesive provided.
7. Locate the unit in the mounting hole, but do
not push it fully in.
8. Route the low voltage cable from the power
supply enclosure to the unit.
9. Pass the low voltage cable through the cable
entry grommet at the top of the unit
(Fig. 24).
10. Secure the unit to the wall using the four
fixing screws provided.
11. Carefully remove the control cover by
undoing the two retaining screws. Take care not
to dislodge the sensor or strain the wires
(Fig. 24).
12. Strip the low voltage cable sheath back
40mm from the end and separate the three
individual wires.
13. Connect the wires to the terminal block.
Connect red to red, white to white and black to
black (Fig. 23).
14. Ensure that the low voltage cable is routed
through the divider slot (Fig. 24).
15. The HR25H unit is factory set to switch
between high or low speed. Two alternative
settings can also be achieved by changing the
position of the ‘jumpers’on the control board
(Fig. 23).
1 Off / Low speed
2 Off / High speed
3 Low / High speed (continuously running)
16. The switching point of the unit can be
adjusted between 60% - 90% humidity. It is
factory set to operate at 70% humidity at 25°C.
17. To adjust the humidity level, rotate switch (A)
as follows (Fig. 23):
a) For the unit to operate at a lower humidity
level, turn switch (A) anti-clockwise (Min. 60%).
b) For the unit to operate at a higher humidity
level, turn switch (A) clockwise (Max. 90%).
18. Reassemble in reverse order ensuring the
divider board seals against the heat exchanger.
19. A bezel is provided to neaten the appearance
of the outside wall around the unit. If required this
should be fixed in place using a suitable
silicone/mastic sealant.
Fig. 20
Fig. 21
Fig. 24
Filter
Removable Grille
Sensor
Divider Board
Grille Surround
Securing Screws
Control Cover
Sensor
External Bezel
Control Cover
Jumpers Fig. 22
Fig. 23
Outside
Wall
Rubber
Seal
25mm
SPEEDS
BLK
BLK
WT
RED
RED
L/H O/H O/L
SPEEDS
L/H O/H O/L
123
Switch (A)
Terminal Block
Divider Slot
Cable Entry
Grommet

3.0 Installation
9
372268 -
3.5 Installing the HR25P
1. Remove the unit, bezel and fixing pack from
the carton.
2. Unclip the removable grille from the unit and
remove filter (Fig. 25).
3. Loosen the two securing screws and remove
the grille surround (Fig. 26).
4. Remove the divider board (Fig. 26).
5. Measure the total wall thickness.
The outer of the two rubber seals is adjustable
and should be set in a position that is 25mm in
from the outer face of the external wall (Fig. 27).
6. Secure the rubber seal to the unit using the
adhesive provided.
7. Locate the unit in the mounting hole but do not
push it fully in.
8. Route the low voltage cable from the power
supply enclosure to the unit.
9. Pass the low voltage cable through the cable
entry grommet at the top of the unit
(Fig. 29).
10. Secure the unit to the wall using the four
fixing screws provided.
11. Carefully loosen the control cover by undoing
the two retaining screws. Slowly pull the cover
forwards. There are two sets of wires leading
from the PIR sensor in the control cover to the
control board. Note the position of these wires
and unplug them at the control board. Place the
control cover to one side (Fig. 29).
12. Strip the low voltage cable sheath back
40mm from the end and separate the three
individual wires.
13. Connect the wires to the terminal block.
Connect red to red, white to white and black to
black (Fig. 28).
14. Ensure that the low voltage cable is routed
through the divider slot (Fig. 29).
15. The HR25P unit is factory set to switch
between high or low speed. Two alternative
settings can also be achieved by changing the
position of the ‘jumpers’on the control board
(Fig. 28).
1 Off / Low speed
2 Off / High speed
3 Low / High speed (continuously running)
16. The unit is designed to operate under two
different conditions, these are as follows:
a) DIRECT ACTION:
This mode effectively means that the PIR sensor
will detect movement within the room and either
switch the unit on, or from the low to high speed
depending upon how it has been set (paragraph
15 above).
b) DELAYED ACTION:
This mode means that the PIR sensor will ignore
movement in the room for the first 2 minutes. This
mode has been designed for night time use of
toilets and bathrooms where brief visits will not
activate the unit.
Fig. 25
Fig. 26
Fig. 29
Filter
Removable Grille
Sensor
Divider Board
Grille Surround
Securing Screws
Control Cover
PIR Sensor
External Bezel
Control Cover
Jumpers Fig. 27
Fig. 28
Outside
Wall
Rubber
Seal
25mm
SPEEDS
BLK
BLK
WT
RED
RED
L/H O/H O/L
BLK
RED
WT
CON 7
CON 5
Switch (A)
Terminal Block
Divider Slot
Cable Entry
Grommet
SPEEDS
L/H O/H O/L
123

3.0 Installation
10
372268 -
3.5 Installing the HR25P (cont)
If any movement is detected after the first 2
minutes, the unit will switch to its higher setting.
This mode has a reset which operates after 5
minutes.
17. Both modes have a timer setting which
determines the length of time the unit runs for
after the last movement detection. This time can
be adjusted using switch (A) between 2 - 27
minutes (Fig. 30).
To increase the time;
turn switch (A) clockwise.
To decrease the time;
turn switch (A) anti-clockwise.
18. Hold the control cover adjacent to the unit
(Fig. 31) and reconnect the plugs to the control
board as follows:
a) Push the red/black connector on to the pins
marked CON 7 (Fig. 34). Ensure that the wires
correspond with the colours marked on the
board. The unit will not operate if connected in
any other way.
b) The purple/white connector determines the unit
mode and should be placed on to CON 5 as
follows:
Delayed Action - Middle and Top pin (Fig. 32)
Direct Action - Bottom and middle pin (Fig. 33)
Note: In either mode the white wire should be on
the lower pin.
The unit will not operate if the connector is fitted
upside down.
19. Replace the control cover with the two
securing screws ensuring that no wires are
trapped.
20. Reassemble the remainder of the unit in
reverse order ensuring the divider board seals
against the heat exchanger.
21. A bezel is provided to neaten the appearance
of the outside wall around the unit. If required this
should be fixed in place using a suitable
silicone/mastic sealant.
SPEEDS
BLK
BLK
WT
RED
RED
L/H O/H O/L
BLK
RED
WT
CON 7
CON 5
WT
CON 5
SPEED
O/H O/L
BLK
RED
WT
CON 7
CON 5
Switch (A)
Fig. 30
Fig. 31
Fig. 32
Delayed Action
Direct Action
Fig. 33
Fig. 34
Control Cover
Purple
White
PIR Sensor
WT
CON 5
Purple
White

3.0 Installation
11
372268 -
3.6 Installing the HR25L, LH & LP
For wall thicknesses between
311mm & 425mm
1. Remove the control cover and disconnect the
red and black motor wires (Fig. 35).
2. Carefully withdraw the heat exchanger from
the unit (Fig. 36).
3. Slide the inner tube out of the unit by pushing
the motor housing (Fig. 37).
4. Remove the plastic ring and rubber seal from
the outer tube (Fig. 38).
Fig. 35
Fig. 36
Fig. 37
Fig. 38
Red and Black
Motor Wires
Control Cover
Heat Exchanger
Motor Housing
Inner Tube
Chassis
Rubber Seal
Plastic Ring
Outer Tube

3.0 Installation
12
372268 -
3.6 Installing the HR25L, LH & LP (cont)
5. Measure the wall thickness and add 25mm.
This is dimension “X”(Fig. 39).
6. Mark off dimension “X”on the outer tube,
measuring from the rear of the chassis. Cut off
the excess material (Fig. 40).
7. Remove any burrs from the tube.
8. Measure the waste from the outer tube and cut
the same amount off the base of the divider
board (Fig. 40).
9. Replace the rubber seal 50mm in from the end
of the tube and secure using the adhesive
provided.
10. Refit the plastic ring using the adhesive
provided.
11. Subtract 1.5mm from dimension “X”. This will
be dimension “Y”.
12. Mark off dimension “Y”from the motor
housing end of the inner tube, and scribe a line
around the inner tube. Peel the two motor wires
away from the wiring tunnel beyond the scribed
line to prevent damage. Carefully cut the excess
off the tube (Fig. 41).
13. Remove any burrs from the tube.
14. Reassemble the tubes in reverse order
ensuring that the two motor wires are located
back in the wiring tunnel, and that the tunnel is
aligned with the wiring slot in the chassis
(Fig. 42).
15. Replace the heat exchanger according to the
‘Inside/Outside’labels. The recess in the heat
exchanger outer must be aligned with the wiring
tunnel on the inner tube to ensure the divider slot
is vertical (Fig. 42 & 43).
16. Cut the two motor wires to size and reconnect
to their respective terminals and replace the
control cover (Refer to the relevant unit
instructions - see pages 8-12 ).
Continue installing the unit from paragraph 7
onwards in the relevant unit instructions - see
pages 8-12.
25mm
(X)
Mounting Hole
Wall Thickness
(X)
Waste
(Y) Waste
Fig. 39
Fig. 40
Fig. 41
Fig. 42
Fig. 43
Chassis
Outer Tube
Inner Tube
Motor Housing
Divider Board
Wiring Slot
Wiring Tunnel
Chassis
Divider Board Slot
Recess
Heat Exchanger

4.0 Maintenance
13
372268 -
4.1 Cleaning the Unit (all models)
Apart from removing odours, providing fresh air
and recovering heat, this unit extracts airborne
impurities such as dust, dirt and grease. These
gradually build up and diminish from the
efficiency and detract from the appearance of
the unit.
To maintain efficiency the unit should be
cleaned at least every six months, or more
regularly if a high level of contamination is
experienced.
1. Isolate the mains power supply.
2. Unclip the removable grille from the unit and
remove filter (Fig. 44).
3. Loosen the two securing screws and remove
the grille surround (Fig. 45).
4. Remove the divider board and slide out the
heat exchanger (Fig. 45 & 46).
5. Wash the grille, surround, filter and heat
exchanger in warm water using a mild detergent
and dry thoroughly.
NOTE: Keep water away from all electrical
components and wiring within the unit.
If it is not possible to fully clean the filter, it must
be replaced (see short parts list on page 15 for
part number).
6. Reassemble in reverse order ensuring the
divider board seals against the heat exchanger.
NOTE: Follow the ‘Inside/Outside’instruction
labels on the heat exchanger.
The recess in the heat exchanger outer wall
must be aligned with the wiring tunnel on the
unit to ensure the divider board slot is
vertical (Fig. 46 & 47).
7. Switch the power supply on and check the
operation of the unit.
Fig. 44
Fig. 45
Fig. 46
Fig. 47
Filter
Removable Grille
Divider Board
Grille Surround
Heat Exchanger
Recess
Wiring Tunnel
Heat Exchanger
Divider Board Slot
Securing Screws

1
23
4
Parts List
5.0 Spares list
5.1 Spares List
Key No. Description Part No.
1 Filter (pack of 4) 370412
2 Heat Exchanger 372329
3 Power supply unit 447249
4 Rubber seal 371297

Introduction
The Guarantee
Applicable only to products installed and used in the United Kingdom. For details of guarantee outside the United Kingdom
contact your local supplier.
Vent-Axia guarantees its products for two years from date of purchase against faulty material or workmanship. In the event of
any part being found to be defective, the product will be repaired, or at the Company’s option replaced, without charge, provided
that the product:-
•Has been installed and used in accordance with the instructions given with each unit.
•Has not been connected to an unsuitable electricity supply. (The correct electricity supply voltage is shown on the
product rating label attached to the unit).
•Has not been subjected to misuse, neglect or damage.
•Has not been modified or repaired by any person not authorised by the company.
IF CLAIMING UNDER TERMS OF GUARANTEE
Please return the complete product, carriage paid to your original supplier or nearest Vent-Axia Centre, by post or personal visit.
Please ensure that it is adequately packed and accompanied by a letter clearly marked “Guarantee Claim” stating the nature of
the fault and providing evidence of date and source of purchase.
The guarantee is offered to you as an extra benefit, and does not effect your legal rights
Head Office: Fleming Way, Crawley, West Sussex, RH10 9YX. Tel: [phone] Fax: [phone]
UK NATIONAL CALL CENTRE, Newton Road, Crawley, West Sussex, RH10 9JA
SALES ENQUIRIES: Tel: [phone] Fax: [phone]
TECHNICAL SUPPORT: Tel: [phone] Fax: [phone]
Web:-www.vent-axia.com Email:- [e-mail]
As part of the policy of continuous product improvement Vent-Axia reserves the right to alter specifications without notice.
447897A 1011