Stuart Turner Mainboost MJ3 VM Guide

- 1 –
Read this manual carefully before commencing installation.
This manual covers all Mainsboost steel vessels for vertical and horizontal units.
Mainsboost Charger Pump MJ3 – Vessel Mounted
Previously named Mainsboost Plus (both vertical & horizontal variants)
Mainsboost Charger Installation,
Operation & Maintenance Instructions
Please leave this instruction booklet with the home owner as it contains
important warranty, maintenance and safety information
CE compliant product
5
WARRANTY
MAINSBOOST

- 2 –
PRODUCT DESCRIPTION
Mainsboost Charger MJ3 consists of three key assemblies, the Mainsboost vessel,
Charger MJ3 pump and upstream line-in kit.
APPLICATION
Mainsboost Charger MJ3 is designed to offer stored clean, potable cold water under
pressure for all domestic or small commercial applications where mains water is
insufficient to offer consistent and reliable water services.
Installation parameters must not exceed the values given in the technical
specifications.
STORAGE
If this product is not to be installed immediately on receipt, ensure that it is stored in a
dry, frost and vibration free location in its original packaging.
CONTENTS Page
Checklist ...........................................................5
Introduction .........................................................9
Important Facts – read before commencing installation ......................10
Location ............................................................11
Terminology .........................................................12
Configuration ........................................................13
Installation ..........................................................15
Electrical ...........................................................23
Commissioning ......................................................25
Technical Specification ................................................28
Trouble Shooting .....................................................30
Warranty ...........................................................31

- 3 –
WARNINGS:
zMainsboost Charger MJ3 system must not be used for
any other application without the written consent of
Stuart Turner Limited.
zThis 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.
zChildren shall not play with the appliance.
zCleaning and user maintenance shall not be made by
children without supervision.
zMaximum head (closed valve) 43 metres.
zThe motor casing can become very hot under normal
operating conditions. Care must be taken to ensure it
cannot be touched during operation.
zThe electrical installation must be carried out
in accordance with the current national electrical
regulations.
zThe electrical installation must be installed by a
qualified person.
zIn the interests of electrical safety a 30 mA residual
current device (R.C.D. not supplied) should be
installed in the supply circuit. This may be part of a
consumer unit or a separate unit.
zBefore starting work on the electrical supply ensure
power supply is isolated.
zDO NOT allow the supply cord to contact hot
surfaces, including the motor shell, pump body or
pipework. The cord should be safely routed and
secured by cable clips.

- 4 –
zThis appliance must be earthed via the supply cord,
which must be correctly connected to the earth
point located in the terminal box.
zThe supply cord and internal wiring within the
terminal box are routed and secured to ensure
compliance with the electrical standard
EN 60335–1. It is essential that prior to any
disturbance of this internal wiring, all cable routing
and securing details are carefully noted to ensure
re-assembly to the same factory pattern is always
maintained.
zIf the supply cord is to be changed or is damaged, it
must be replaced with a special cord assembly
available from Stuart Turner or one of their approved
repairers.
Please read installation details carefully as they are intended to ensure this product
provides long, trouble free service. Failure to install the unit in accordance with the
installation instructions will lead to invalidation of the warranty. These instructions
must be left with the product.

- 5 –
CHECKLIST
Item Description Qty Item Description Qty
Package
1a
1 Monobloc unit 1 Package
21Mainsboost vessel 1
2 ¼ “ BSP Pressure gauge 2
Package
3
1 Pump 1
3 Lever isolating ball valve 1 2 Manifold Assy 1
4Mainsboost vessel
connector fitting 1 3 Hose 2
522/28mm compression
adaptor 2 4 Sealing washer 2
5Pump mounting
bolt assemby 1 set
6Pump mounting
bolt assembly 1 set
Your product may vary slightly from the illustrations above.
Mainsboost Charger MJ3 (Vertical) + Mainsboost Monobloc 22/28mm ULK
IMPORTANT: Your Mainsboost Charger MJ3 system will be delivered in a minimum of
three boxes on one pallet. Please check the contents within 24 hours of receipt and
if any component is damaged, please contact Stuart Turner Ltd immediately.
Package 2
Mainsboost vessel
Fig. 3
1
Package 1a
Monobloc 22/28mm Upstream line-in kit
Fig1a
Package 3
MJ3 pump
Fig. 2 4
3
2
1
5
6
5
4
2
3
1

- 6 –
CHECKLIST
Item Description Qty Item Description Qty
Package
1b
1 ¼ “ BSP pressure gauge 1 Package
21Mainsboost vessel 1
2 Lever isolating ball valve 1
Package
3
1 Pump 1
3Mainsboost vessel
connector fitting 1 2 Manifold Assy 1
46 bar pressure regulating
valve 1 3 Hose 2
5 ¼ x ½ “ BSP Brass bush 1 4 Sealing washer 2
6 Y pattern inline strainer 1 5 Pump mounting
bolt assy 1 set
7Double check valve 1 6 Pump mounting
bolt assy 1 set
8 ¼ “ BSP Pressure gauge 1
Your product may vary slightly from the illustrations above.
Mainsboost Charger MJ3 (Vertical) + 35/42/54mm ULK
IMPORTANT: Your Mainsboost Charger MJ3 system will be delivered in a minimum of
three boxes on one pallet. Please check the contents within 24 hours of receipt and
if any component is damaged, please contact Stuart Turner Ltd immediately.
Package 2
Mainsboost vessel
Fig. 3
1
6
Package 1b
Upstream line-in kit 35/42/54mm
Fig. 1b
61
48
5
2
7
3
Package 3
MJ3 pump
Fig. 2
4
3
2
1
5
6

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CHECKLIST
Mainsboost Charger MJ3 (Horizontal) + Mainsboost Monobloc 22/28mm ULK
(compatible with MB 200SH and MB 250SH vessels only)
Your product may vary slightly from the illustrations above.
Item Description Qty Item Description Qty
Package
1a
1 Monobloc unit 1 Package
2
1Mainsboost vessel 1
2 ¼ “ BSP Pressure gauge 2 2 Mounting cradle 2
3 Lever isolating ball valve 1
Package
3
1 Pump 1
4Mainsboost vessel
connector fitting 1 2 Sealing washers 2
522/28mm compression
adaptor 2 3 Manifold assembly 1
4 Hoses 2
5Pump mounting
bolt assy 1 set
6MJ3 HM mounting
bracket 1
Package 2
Vessel/Mounting Cradle
Fig. 3
1
2
41
3
5
Package 3
MJ3 pump
Fig. 2
6
2
Package 1a
Monobloc 22/28mm Upstream line-in kit
Fig1a
5
4
2
3
1

- 8 –
CHECKLIST
Mainsboost Charger MJ3 (Horizontal) + 35/42/54mm ULK
(compatible with MB 200SH and MB 250SH vessels only)
Your product may vary slightly from the illustrations above.
Item Description Qty Item Description Qty
Package
1b
1 ¼ “ BSP pressure gauge 1 Package
2
1Mainsboost vessel 1
2 Lever isolating ball valve 1 2 Mounting cradle 2
3Mainsboost vessel
connector fitting 1
Package
3
1 Pump 1
46 bar pressure regulating
valve 1 2 Sealing washers 2
5 ¼ x ½ “ BSP Brass bush 1 3 Manifold assembly 1
6 Y pattern inline strainer 1 4 Hoses 2
7Double check valve 1 5 Pump mounting
bolt assy 1 set
8 ¼ “ BSP Pressure gauge 1 6 MJ3 HM mounting
bracket 1
6
Package 1b
Upstream line-in kit 35/42/54mm
Fig. 1b
61
4
8
5
2
7
3
Package 2
Vessel/Mounting Cradle
Fig. 3
1
2
4
2
1
3
5
Package 3
MJ3 pump
Fig. 2
6

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1 INTRODUCTION
1.1 Congratulations on buying a Mainsboost Charger MJ3 system, designed to
offer consistent and reliable water services throughout the property.
1.2 Patents, Trademarks & Trade Names:
‘Mainsboost’ ‘Mainsboost Plus’ and ‘Mainsboost Charger’ are registered
Trademarks of Stuart Turner Ltd.
1.3 How the Mainsboost Charger MJ3 System works:
The Mainsboost Charger MJ3 vessel stores water from the rising main in a
sealed water chamber, separated from the air space by a rubber diaphragm
and pressurised to an optimum setting. When water is drawn off by
downstream services, the water from the mains is supplemented by the
water from the Mainsboost Charger MJ3 unit to provide a balanced supply at
consistent pressure to downstream services.
The Mainsboost Charger MJ3 pipework manifold incorporates a unique ‘green
energy’ bypass. If the incoming mains water supply delivers more than
12 l/min this bypass should be left open to allow any additional flow rate to
pass directly into the Mainsboost vessel via the integral non-return valve.
If the incoming flow rate is less that 12 l/min the bypass valve should
be left closed in order to ensure optimum efficiency of the Charger MJ3 pump.

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2 IMPORTANT FACTS READ BEFORE COMMENCING INSTALLATION
A Commissioning
2.11 Ensure the pump is primed as described in the priming section before
starting, damage to the shaft seal will result otherwise. See Section 8.16 –
Commissioning.
B Water temperature
This unit is designed for cold water applications only which should not exceed the
following values:
2.12 The maximum allowable water temperature is 35 oC.
2.13 The minimum allowable water temperature is 4 oC.
C Pipework – General
2.14 Secure pipework: Ensure pipework to and from the Mainsboost Charger MJ3
is independently supported & clipped to prevent forces being transferred to
inlet and outlet branches of pump. Flexible hoses supplied must be used.
2.15 Flux: Solder joints must be completed and flux residues removed prior to
pump installation (flux damage will void any warranty).
2.16 Pipework design: Care should be taken in the design of pipework runs to
minimize the risk of air locks e.g. use drawn bends rather than 90obends.
D Plumbing Installation Regulations
2.17 The plumbing installation must comply with the current water and building
regulations.
2.18 The plumbing installation must be installed by a qualified person.
E Mainsboost vessel
2.19 Ensure the Mainsboost vessel is installed correctly before operating the unit,
to avoid damage to the pumps/controls.
Do not attempt to dismantle the Mainsboost vessel
The Mainsboost vessel is pressurised to a pre-set level at the factory.
See Section 8.12 – Commissioning for details.

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3 LOCATION  GENERAL
3.11 Access: For emergencies and maintenance the Mainsboost
Charger MJ3 must be easily accessible.
3.12Protection: The system must be located in a dry position, and
protected from freezing. Avoid environments which have a high
ambient temperature, high humidity or excessive condensation
and salt damage, etc.
3.13 Ventilation: Ensure an adequate air flow to cool the pump.
Separate the pump from other appliances that generate heat.
3.14 Safety: The motor casing can become very hot under normal
operating conditions. Care must be taken to ensure it cannot be
touched during operation.
3.15 Water retention: Site the pump in a location where in the unlikely
event of a water leak, any spillage is contained or routed to avoid
electrics or areas sensitive to water damage.
3.16 Static inlet pressure: Ensure the static inlet head at the pump does not
exceed the values shown in the table under point 8.14.
3.17 Incoming mains water pressure: The incoming water pressure of at least
0.1 bar is required.
3.18 Ensure that location of the unit allows adequate space to give reasonable
access to all parts to accommodate service/commissioning.
3.19 Ambient temperature: The pump must be sited in a location where the
maximum ambient temperature does not exceed 40 oC.
3.20 Pipework: Pipework should be sized to ensure optimum performance of the
system.
3.21 Direction of flow: See Fig. 4 (vertical), Fig. 5 (horizontal) to identify the
suction and discharge connections.
Vertical
Fig. 4
Suction
Discharge
Horizontal
Fig. 5
Suction
Discharge

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4 TERMINOLOGY
4.11 Upstream Line-in Kits (ULK)
Monobloc upstream line-in kit:
The Mainsboost Monobloc is a patent pending mains regulating device
and should be installed on the rising main between the stopcock and the
Mainsboost vessel. The Monobloc unit is used on 22mm or 28mm upstream
line in kits.
Upstream line-in kits:
Upstream line-in kits for 35mm, 42mm & 54mm installations use separate
regulating components and should be installed on the rising main between
the stopcock and the Mainsboost vessel.
4.12 System Designation
It is important to understand what upstream and downstream refers to before
starting the installation.
Upstream
The term ‘Upstream’ refers to the system configuration from the consumer’s
stopcock to the point where the supply reaches the inlet port of the
Mainsboost vessel.
Downstream
The term ‘Downstream’ refers to the system configuration from the outlet
tapping on the Mainsboost vessel, along the distribution header (if configured
in this way) and into the distribution pipework and outlets. This includes hot
and cold services where both are present (see Fig. 6).
UPSTREAM DOWNSTREAM
UPSTREAM
LINE-IN KIT
Fig. 6 System designation

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5 CONFIGURATION
5.11 Mainsboost Charger MJ3 is a very flexible solution, offering a packaged
system to suit any type or size of building no matter how large or small the
demand is. The following illustrations depict just some of the most typical
installations.
5.12 Single occupancy application:
Use of Mainsboost Charger
MJ3 in a house offers water
on demand whilst giving
maximum flexibility. As can
be seen the upstream
line-in kit has to be fitted on
to the rising main but the
vessel/pump can be fitted
wherever there is a space,
for example; utility, kitchen,
upstairs cupboard or loft,
providing adequate
provisions are taken for the
weight, frost protection
etc (see Fig 7).
Where height restrictions
exist the MJ3 HM pump can
be supplied along with a
MB 200SH or MB 250SH
vessel for horizontal
installation.
5.13 Multiple occupancy application:
Often affected by poor water
supplies Mainsboost Charger
MJ3 offers the perfect
solution.
For multiple occupancy
buildings again the
upstream line-in kit is located
next to the rising main and
sized to meet the demand of
the entire building. Each
apartment then has its own
vessel and pump located
within the property, sized to
meet the apartments own
demand (see Fig. 8).
UPSTREAM
IN LINE KIT
Fig. 7
A
UPSTREAM
IN LINE KIT
Fig. 8

- 14 –
5.14 High demand single occupancy application:
Where single properties have a much highter demand, it may be necessary
to use additional Mainsboost vessels connected in parallel to ensure sufficient
water is on tap to meet the much higher demand. Fig. 9 shows all vessels
being located in the same place.
5.15 Water softener:
NOTE: If high pressure is also required to the drinking tap fit a Stuart Water
Conditioner, available from Stuart Turner, rather than a water softener.
UPSTREAM
LINE-IN KIT
Fig. 9
UPSTREAM
LINE-IN KIT
Fig. 10 Water softener

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6 INSTALLATION
Vertical Step 1:
a) Remove the Mainsboost vessel from its packaging and check to ensure it is
not damaged.
b) Carefully turn the vessel on its side using the discarded packaging to protect
it.
WARNING: depending on cylinder size this may require two people
to complete safely.
c) Once on its side screw the Mainsboost vessel connector provided in the
upsteam line-in kit into the tank elbow at the base using suitable thread seal
such as PTFE tape or liquid thread lock (see Fig. 11).
d) Cut a copper tail to the following minimum length, ensuring clearance of the
base, and push into vessel connector.
Pipe length:
MB 100SV = 210 mm MB 200SV = 270 mm MB 300SV = 270 mm
MB 130SV = 210 mm MB 250SV = 270 mm MB 450SV = 340 mm
Then re-erect the cylinder.
e) Fit the isolating valve provided to the tail now protruding from the base of the
vessel.
NOTE: It is good practice to install a drain port between the isolation valve and the
vessel.
f) Remove the pump and mounting plate from its packaging and position it on
the Mainsboost vessel, fixing in place using the correct size screw and
washers provided (see Figs. 12 & 13).
Fig. 11
Pump mounting for 200, 250, 300 & 450 litre
vessels. Fig. 13
Bolt 3/8 " or M8
Washer
Item 5, threaded
insert 5/8 " – 3/8 "
Or
Item 6, threaded
insert ½ “ – M8
Pump mounting for 100, 130 litre vessels
Fig. 12
Bolt 3/8 "
Washer
Vessel Connetor
Isolation Valve

- 16 –
g) Ensure the floor is sufficiently strong enough to take the total weight of the
unit when full of water (see Technical Specification section). Take care when
manoeuvring the unit so as not to damage it.
NOTE: Do not forget if a water softener is to be installed this has to
be included in this pipe run, and additional space must be allocated
for this.
Do not fit smaller pipework than the upstream line-in kit accepts as
this will impair performance.
h) Fix the Mainsboost vessel securely to the floor using appropriately selected
and sized fixings.
Pump manifold assembly:
Vertical variant: Remove the pump manifold assembly from the packaging and
connect it to the pump assembly using the two fibre washers provided.
Fig. 14
Vertical
Fig. 15
Inlet
Manifold assembly
Outlet
Sealing
washers
Bypass valve and
integral NRV

- 17 –
Vertical Step 2:
The vessel assembly should then be positioned and checked to ensure there is
sufficient space to install the upstream line-in kit between the stopcock and
pressure vessel inlet.
Monobloc 22/28mm Upstream line-in kit
The Monobloc upstream line-in kit includes:
1 – Monobloc unit
2 – Pressure gauge (upstream)
3 – Pressure gauge (downstream)
4 – Mainsboost vessel connector (see step 1)
5 – Isolation valve (See step 1)
NOTE: the Monobloc can be installed either horizontally or vertically but not upside
down. There are pressure gauge ports on both sides of the Monobloc to allow the
pressure gauges to be visable in any orientation. Follow the directional flow arrows
on the Monobloc to ensure correct installation.
Upstream line-in kit 35/42/54mm
The upstream line-in kit includes:
1 – inline strainer
2 – pressure gauge (upstream)
3 – double check valve
4 – pressure reducing valve
5 – pressure gauge
(fitted to pressure reducing valve)
6 – Mainsboost vessel connector (see step 1)
7 – Isolation valve (See step 1)
Pipe
Size
Minimum pipe length required to install the
upstream line-in kit (mm) (A)
22 mm 480 mm
28 mm 580 mm
35 mm 630 mm
42 mm 735 mm
54 mm 820 mm
DIRECTION
OF FLOW
Fig. 16b
5
3
A
4
2
1
Pipe
Size
Minimum pipe length required to install the
Monobloc upstream in line kit (mm) (A)
22 mm 203 mm
28 mm 203 mm A
Fig. 16a
3
1
2

- 18 –
Horizontal Step 1:
a) Remove the Mainsboost vessel from its packaging and check to ensure it is
not damaged.
b) Carefully place the vessel on the mounting cradles. For stability, ensure the
mounting cradles are as far apart as possible but within the weld seams
Fig. 18b.
WARNING: depending on cylinder size this may require two people
to complete safely.
Remove the skirt by splitting open the clip as shown in Fig. 18a.
Vertical vessel
Fig. 17a Monobloc 22/28mm ULK
10 - 30 mm
Removal of skirt
Fig. 18a
10 - 30 mm
Mounting cradle
placement Fig. 18b
Fig. 17b 35/42/54mm ULK

- 19 –
c) Remove the pump and mounting bracket from its packaging and assemble as
shown in Figs. 19, 20 & 21.
d) Connect the supplied hoses, Fig. 22.
Inlet
Outlet
Manifold
assembly
Bypass valve and
integral NRV
Fig. 22
Sealing
washers
Pump mounting bracket assembly
Fig. 19
3/8 " bolt
Mounting bracket
Mounting pump onto the vessel
Fig. 20
Clean surface with
wipes (included)
Remove
protective
covers
Correct pump mount orientation
Fig. 21
3/8 " nut
Washer
Washer

- 20 –
Horizontal Step 2:
The vessel assembly should then be positioned and checked to ensure there is
sufficient space to install the upstream line-in kit between the stopcock and
pressure vessel inlet. Refer to the chart below as a guide.
Monobloc 22/28mm Upstream line-in kit
The Monobloc upstream line-in kit includes:
1 – Monobloc unit
2 – Pressure gauge (upstream)
3 – Pressure gauge (downstream)
4 – Vessel Connector (see step 1)
5 – Isolation Valve (see step 1)
NOTE: the Monobloc can be installed either horizontally or vertically but not upside
down. There are pressure gauge ports on both sides of the Monobloc to allow the
pressure gauges to be visable in any orientation. Follow the directional flow arrows
on the Monobloc to ensure correct installation.
NOTE: It is good practice to install a drain port between the isolation valve and the
vessel.
1 Monobloc unit
2 Pressure gauge (upstream)
3 Pressure gauge (downstream)
4Mainsboost vessel connector
5Lever isolating valve
Fig. 24a
Pipe
Size
Minimum pipe length required to install
the Monobloc upstream in line kit (mm) (A)
22 mm 203 mm
28 mm 203 mm
A
Inlet
Outlet
1
2
Flexible
hose
4
5
Flexible
hose
3
Fig. 23a
Push fit elbow
(not supplied)
T-piece (not supplied)