Nuaire Group MRXBOX95-WM2

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The unit must remain switched on at all times to maintain

ventilation within the dwelling. Turning the unit off will

cause long term damage to the unit and building fabric.

This appliance is not intended for use by persons

(including children) with reduced physical, sensory or

mental capabilities, or lack of experience and knowledge,

unless they have been given supervision or instruction

concerning the use of the appliance by a person for their

safety. Children should be supervised so that they do not

play with the appliance.

MRXBOX95-WM2

Mechanical Ventilation Unit with Heat Recovery

for Wall Mounting

Installation and Maintenance

1.0 Introduction

MRXBOX95-WM2 wall mounted unit is designed to provide

mechanical supply and extract ventilation with heat recovery.

The unit is fitted with two independent fans. Each fan has full

speed control for background and boost ventilation rates.

To recover heat from the extract air the heat exchanger block

is utilised. The heat exchanger can recover up to 90% of the

normally wasted heat.

2.0 Installation

Installation must be carried out by competent personnel in

accordance with the appropriate authority and conforming

to all statutory governing regulations. All mains wiring must

be in accordance with the current I.E.E. Regulations, or the

appropriate standards. Ensure that the mains supply

(Voltage, Frequency and Phase) complies with the rating label.

Please note a clear working space is required around the

installed unit to allow the cover to be removed and provide

sufficient access for maintenance such as filter change.

Please allow a minimum of 350mm in front of the unit.

The fan must be installed indoors, on a suitable wall away

from direct sources of frost, heat, water spray or moisture

generation. For a vibration-free result the unit must be

mounted to a solid wall.

The unit is designed for wall mounting only via a patress.

1. One part of the mounting bracket should be offered up to

the wall, ensuring it’s located horizontally. Mark the fixing

points through the pre drilled holes in the bracket and

install with screws (by others), ensuring the interlock side

is at the top, fig. 2.

2. Fix the remaining part of the bracket to the unit using the

M5 screws ensuring the interlock side is at the bottom, fig.3a.

3. Install the unit on the wall by ensuring the bracket on the

unit interlocks over the wall mounted bracket (fig. 3b).

Note: Care must be taken to ensure the unit is installed true

in all 3 dimensions. Failure to do so may result in overflow

from the internal condensation drip tray.

Nuaire Limited Western Industrial Estate Caerphilly United Kingdom CF83 1NA

T: 029 2085 8400 F: 029 2085 8444 E: info@nuaire.co.uk W: www.nuaire.co.uk

08. 05. 14. Leaflet Number 671588

Extract air

from house

Intake air

from outside

Exhaust air

from house

to outside

Supply air

to house

Figure 1. Airflow through unit.

The EMC Directive

2004/108/EC

The Low Voltage

Directive

2006/95/EC

Figure 3a. Fixing the mounting

bracket to the rear of unit.

Pre-fitted

support feet

Bracket

Figure 3b. Mounting the unit

on the wall mounted bracket.

Figure 2. Fixing the mounting bracket to the wall via a patress.

125mm dia.

ducting in

ceiling void.

First floor ceiling.

Side view of unit

mounted on the

wall in a cupboard.

(Note: The unit must

be fixed to a suitable

patress in upright

position as shown to

comply with safety

regulations).

MVHR-DRAIN

Condensate drain,

uninsulated drain

pipe with 10

fall

running to SVP.

Supply air valve in ceiling.

Figure 4. Typical example of a cupboard mounted unit on a patress

using the bracket.

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This document provides comprehensive installation and maintenance instructions for the Nuaire MRXBOX95-WM2 Mechanical Ventilation Unit with Heat Recovery, a wall-mounted system designed to ensure continuous ventilation and heat recovery within a dwelling.

Function Description

The MRXBOX95-WM2 is a mechanical ventilation unit with heat recovery (MVHR) designed to provide balanced supply and extract ventilation. It features two independent fans, each with full speed control for both background and boost ventilation rates. The core function of the unit is to recover heat from the extracted air, utilizing a heat exchanger block that can recover up to 90% of normally wasted heat. This process ensures a continuous supply of fresh, filtered air into habitable rooms while extracting stale, moist air from wet rooms, all while minimizing heat loss. The unit is designed to remain switched on at all times to maintain optimal ventilation, as turning it off can lead to long-term damage to both the unit and the building fabric.

Usage Features

The MRXBOX95-WM2 is intended for indoor installation on a suitable solid wall, away from direct sources of frost, heat, water spray, or moisture generation, to ensure vibration-free operation. It is designed for wall mounting only via a patress.

Installation:

Mounting Bracket: One part of the mounting bracket is fixed to the wall horizontally using screws, ensuring the interlock side is at the top. The remaining part of the bracket is then fixed to the unit using M5 screws, with the interlock side at the bottom.
Unit Installation: The unit is then installed on the wall by interlocking the unit-mounted bracket over the wall-mounted bracket. It is crucial to ensure the unit is installed true in all three dimensions to prevent overflow from the internal condensation drip tray.
Condensate Drain: The condensate must be discharged under a water level in a U-trap drainpipe or an alternative airlock-acting drain method. The connection is suitable for 21.5mm diameter overflow pipe, with solvent cement recommended for joints. If a U-trap is used, it must be filled with water to avoid airlocks. If the condensation pipe is in an unheated space, it should be insulated to prevent freezing. Nuaire recommends using MVHR-DRAIN as the primary condensate take-off.
Ducting: Rigid ducting is recommended at all times, with flexible ducting kept to a minimum (maximum 500mm per leg) and pulled taut to minimize resistance. Ducts between the MVHR unit and the atmosphere should be insulated to prevent condensation. Ducting should be installed to minimize airflow resistance, with bends kept to a minimum and a minimum distance of 200mm between the appliance and any bends. Ideally, 150mm diameter or 204 x 60mm rectangular ducting should be used. Ducting joints must be sealed with silicone sealant and reliably fixed to the appliance.
Air Permeability and Infiltration: The unit's design considers air permeability and infiltration allowances as per ADF2006 and ADF2010 building regulations.
Ventilation Flow Rates: The unit's airflow rates are determined based on the number of bedrooms and the type of room (kitchen, utility, bathroom, sanitary accommodation) to meet minimum high and low extract rates, as well as whole dwelling ventilation rates.
Electrical Connection: The electrical connection must be carried out by a qualified electrician. The unit is supplied with a flexible cord for connection to the mains supply (240V, 1ph, 50Hz, 1.3 Amp consumption, 3 Amp fuse rating). The unit must be earthed, and the three-core cable from the mains power supply should be connected to a fixed wiring installation via a fused isolator, in accordance with current IEE wiring regulations. Sensor cables or switched live cables should not be placed within 50mm of other cables or on the same metal cable tray.
Commissioning: Correct commissioning is essential to ensure specified ventilation airflow rates are met and to prevent excessive power consumption. Commissioning should be carried out using a calibrated moving vane anemometer and hood. Adjustment valves should be locked in place post-commissioning to prevent tampering. The unit's control panel allows for independent control of normal and boost airflows.
Summertime Boost: The unit has a summertime boost facility that allows it to operate at maximum airflow, overriding trickle and boost speeds.

Maintenance Features

Regular maintenance is crucial for the optimal performance and longevity of the MRXBOX95-WM2 unit.

Filter Maintenance: The two G3 filters should be inspected after 6 months and replaced every 12 to 18 months. To access the filters, remove the two filter covers on the front panel by taking hold of the circular tabs and pulling them out. The filters can then be extracted by pulling the removal loop on their front edge.
Heat Exchanger Inspection: The heat exchanger should be inspected every 5 years for damage and component security.
Component Replacement: Nuaire maintains extensive stocks of spare parts for quick delivery. Before replacing any component, ensure the unit is electrically isolated from the mains supply and switched live supply. The supply cable must be replaced by an electrically competent person. When ordering spare parts, quote the unit's serial number and ARC number.
Access for Maintenance: A clear working space (minimum 350mm in front of the unit) is required to allow the cover to be removed and provide sufficient access for maintenance, such as filter changes. The unit should be installed in a position that permits access for maintenance purposes.
Handover and Advice: Customers should be provided with documentation detailing maintenance and operational requirements. They should be advised that opening windows is not recommended during normal use to ensure energy-efficient operation, not to seal natural airflows between rooms (e.g., avoid door seals), not to alter settings post-commissioning, and to clean filters as per manufacturer instructions.

The MRXBOX95-WM2 is designed for ease of use and maintenance, ensuring a healthy and energy-efficient indoor environment when properly installed and cared for.

Nuaire Group MRXBOX95-WM2 Specifications

General

Model	MRXBOX95-WM2
Category	Fan
Manufacturer	Nuaire Group
Airflow	95 l/s
Heat Recovery Efficiency	Up to 95%
Dimensions	590mm (W) x 450mm (H) x 267mm (D)
Weight	12.5kg
Mounting	Wall-mounted
Voltage	230 V
Frequency	50 Hz