Vent-Axia MULTIVENT MVDCH Manual instruction

Installation and Wiring Instructions for the Multivent Humidistat Extract Fans.
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MULTIVENT MVDCH
VENTILATION SYSTEM
Installation, Set-up and Operating Instructions
Stock Ref.No
18 30 20B

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IMPORTANT:
READ THESE INSTRUCTIONS BEFORE COMMENCING THE INSTALLATION
DO NOT install this product in areas where the following may be present or occur:
•Excessive oil or a grease laden atmosphere.
•Corrosive or flammable gases, liquids or vapours.
• Ambient exhaust air temperatures higher than 40°C or less than –5°C.
•Relative humidity above 90%
• Possible obstructions which would hinder the access or removal of the Unit.
•Sudden ductwork bends or transformations close to the Unit.
SAFETY AND GUIDANCE NOTES
A. All wiring must be in accordance with the current I.E.E. Regulations, or the appropriate standards of your country
and MUST be installed by a suitably qualified person.
B. The Unit should be provided with a local double pole isolator switch having a contact separation of at least 3mm.
The fuse rating should be 3A.
C. Ensure that the mains supply (Voltage, Frequency and Phase) complies with the rating label.
D. The Unit should only be used in conjunction with the appropriate Vent-Axia products.
E. It is recommended that the connection to the unit is made with flexible cable/conduit.
F. The Unit should not be sited within 600mm horizontally of/or 2250mm vertically of a bath/shower tray, in
accordance with the current I.E.E. Regulations for bathrooms.
G. When the unit is used to remove air from a room containing a fuel-burning appliance, ensure that the air
replacement is adequate for both the fan and the fuel-burning appliance.
H. The installer must ensure that the Unit intake is located a minimum of 600mm from any flue outlet.
I. This Unit is designed as an inline ducted unit to be positioned between lengths of ducting. Short duct runs
terminating within 1.5m must incorporate suitable guards unless the unit is mounted higher than 2.3m.
J. This Unit should not be used where it is liable to be subject to direct water spray from hoses etc.
K. This Unit handles moisture-laden air, ensure that a condensation drain is fitted.
L. Certain applications may require the installation of sound attenuation material to achieve the sound levels
M. Ducted ventilators must be vented to the outdoors.
TYPICAL INSTALLATION

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INTRODUCTION NOTES.
The MULTIVENT range is designed for simultaneous ventilation for a maximum of up to four separate areas such as
bathrooms, kitchens and toilets. The range can be mounted in three different orientations for convenient installation
in roof voids with a height of 250mm or greater. An integral humidistat is provided to automatically trigger an
increased airflow in order to quickly remove any build up of humid air caused by showers, cooking etc.
The MVDCH(RF) employs a highly efficient backward curved centrifugal motor impeller set. The model is designed
for continuous 24-hour use and should not be used in conjunction with a delay timer.
HUMIDISTAT.
The humidity set point is adjustable between 60% and 90% RH with a mid point potentiometer setting of 75% RH.
Once a humidity level is detected above the set point value, the Multivent will initiate a fixed airflow boost cycle
depending on the initial speed setting of unit when the humidity rise was detected.
REMOTE CONTROL (OPTIONAL EXTRA).
Operation of the MVDCH(RF) model can be controlled with a hand held wireless transmitter, available separately.
The transmitter is switchable between low, medium and high (boost) speed operation. The default power-on speed
setting is low. The transmission signal will function over a range of at least 10m through 2 concrete block/beam
floors. 16 unique code selection features are available to match the transmitter to the Multivent receiver and so avoid
any possible cross talk between adjacent property installations.
It is possible to have more than one transmitter unit dedicated to a given Multivent unit and vice versa as the
installation dictates. Each transmitter is provided with a wall mountable holder.
SITING
The MULTIVENT may be mounted in three orientations.
a). Base mounted Installation with ducting radiating out horizontally. The Condensate Drain is on the opposite side
to the exhaust spigot at the base of the unit.
CondensateDrain
On the unit housing.
b). Vertically mounted Installation with the exhaust spigot at top. The Condensate Drain is opposite to the exhaust
spigot at the base of the unit. Additional drainage may be required from the duct connected to the bottom spigot.
Condensate Drain
On the unit housing.
c). Ceiling mounted Installation. The Condensate Drain is opposite to the exhaust spigot under the lid of the unit.
Additional drainage may be required.
Condensate Drain
Under the lid.

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See the dimensional details below for the mounting hole positions.
Condensate Drain Condensate Drain
On the unit housing. Under the lid.
INSTALLATION
1. Position the MULTIVENT, taking into consideration the position of the rooms to be ventilated, the exhaust
position, the drainage position and the electrical services. Ensure there is adequate access for installation and
maintenance. Securely mount the MULTIVENT through the mounting brackets on the casing using the
appropriate anti-vibration mounts, screws, washers, rubber bushes etc.
2. Where the intake and exhaust ducts are to be connected to the MULTIVENT, remove the spigot caps if 125mm
ducting is being used. If 100mm ducting is being used, peel out the centre of the cap with a screwdriver as
indicated and leave the cap surround in position. To connect ducting to the base intake, use a suitable adaptor
attached using the 4 holes provided.
3. Ducting passing through an unheated roof void should be insulated. Ducting runs should be as straight as
possible and intake ducting should slope downwards from Under the lid. Connect ducting to the MULTIVENT
spigots and to appropriate ceiling terminations.
4. Select the drain spigot required, remove the “Knockout” and connect a suitable drainage system.
WIRING
WARNING: THE MULTIVENT AND ANCILLARY CONTROL EQUIPMENT MUST BE ISOLATED
FROM THE POWER SUPPLY DURING THE INSTALLATION / OR MAINTENANCE.
THE MULTIVENT UNIT MUST BE EARTHED.
1. Connect mains supply as (Fig. 1).
2. Check that all connections have been made correctly. Ensure that all terminal screws and cable clamps are
securely fastened.
3. The cable entry must be made using a suitable grommet or cable gland.
4. After performing the following set-up instructions, switch the mains supply on and check the system is operating
correctly.
CONNECTION DIAGRAM
Switched Fused Spur
1 Phase Supply
(220-240V 50Hz). ~
L
N
E
N
L
3A FUSE
E
Fig 1

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HUMIDITY ADJUSTMENT.
Adjust potentiometer to the required humidistat setting, Fig. 2. To increase the humidistat set point, rotate the
adjuster anticlockwise and to decrease the humidistat set point rotate the adjuster clockwise.
The Multivent reacts automatically to an increase in %RH above the set point value.If high humidity is detected, the
fan speed increases to medium for 30 minutes. At the end of this period, if high humidity is still detected, the fan
speed increases to high for 15 minutes. At the end of this period, if the humidity is low, the fan returns to its original
low setting, but if still high, the fan reverts back to medium speed for 30 minutes and so on.
OVER-HEATING PROTECTION
The MULTIVENT motor is fitted with Standard Thermal Overload Protection. This will automatically switch the fan Off
in the event of a fault condition.
If this occurs isolate the MULTIVENT, check for and remove any obstruction, leave for a short time for the motor to
cool before reconnecting. If this recurs, Isolate the MULTIVENT and call a service engineer.
Humidity adjustment
Fi
g
. 2

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WIRELESS CONTROLLER (Available stock ref. 426035)
The selection switch in the Multivent unit and the switch in the hand held transmitter must be set exactly the same.
The factory setting is 5678 but it is inadvisable to retain this setting.
a) The Multivent Selection Switch.
Located as shown in Fig 3.
b) The Transmitter Selection Switch
•Remove battery compartment cover on the back of the transmitter unit.
•Set the transmitter selection switch to the same number sequence as used for the Multivent receiver,
see Fig 4.
•Connect battery terminal connector to the battery.
PP3 9V BATTERY
SELECTION SWITCH
Fi
g
3
Fig 4

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c) Humidity Response :
The Multivent reacts automatically to an increase in %RH above the set point value and the manner in which this
triggers will increase airflow depending on the original speed setting, as follows:
Low Speed Setting: If high humidity is detected, the fan speed increases to medium for 30 minutes. At
the end of this period, if high humidity is still detected, the fan speed increases to
high for 15 minutes. At the end of this period, if the humidity is low, the fan returns to
its original low setting, but if still high, the fan reverts back to medium speed for 30
minutes and so on.
Medium Speed Setting: If high humidity is detected, the fan speed stays at medium speed for 30 minutes. At
the end of this period if high humidity is still detected, the speed increases to high
for 15 minutes and drops back to the original medium speed setting at the end of
this period.
High Speed Setting: If high humidity is detected there is no speed change. However, at the end of 30
minutes the boost time-out will automatically reset the fan speed back to low.
In all the automatic humidity operating modes, it is possible to override any humidity cycles in progress and switch
the fan to any other speed. However, if high humidity is still present, the unit will revert back to the appropriate
automatic humidity cycle operation.

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Head Office: Fleming Way, Crawley, West Sussex RH10 9YX
Tel: [phone] Fax: [phone]
Internet site at: www.vent-axia.com
VENT-AXIA CONTACT NUMBERS
UK NATIONAL SALES CENTRE
Domestic & Commercial Industrial
Tele: 01293 530202 Tele: 01293 441570
Fax: [phone] Fax: [phone]
REPUBLIC OF IRELAND
Vent-Axia Ventilation Ltd.
921 Western Road Industrial Estate
Naas Road, Dublin 12.
Tele: [phone]
Fax: [phone]
UK NATIONAL TECHNICAL SUPPORT
Domestic & Commercial Industrial
Tele: 01293 526062 Tele: 01293 455196
Fax: [phone] Fax: [phone]
Internet site at: www.vent-axia.com Email: [email protected]
The Vent-Axia Guarantee
Applicable only to products installed and used in the United Kingdom. For details of the Guarantee
outside of the United Kingdom contact your local supplier.
Vent-Axia guarantees this product for two year from the 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 discretion the product will be replaced without charge, provided that the product:
1). Has been installed and used in accordance with the instruction given with each unit.
2). The electricity supply complies with the rating label.
3). Has not been misused, neglected or damaged.
4). Has not been modified or repaired by any person not authorized to do so by Vent-Axia.
IF CLAIMING UNDER THE TERMS OF THE GUARANTEE
Please return the complete product, carriage paid to your original supplier by post or in person. Please
ensure that it is adequately packed and accompanied by a letter clearly marked ‘Guarantee Claim’
stating the nature of the fault and providing proof of the date and source of purchase.
As part of the policy of continuous product improvement
Vent-Axia reserve the right to alter specifications without notice
426336 D 0807