Stuart Turner Monsoon U1.5 bar Twin User manual

Installation Instructions
For Monsoon Universal
Twin Pump
Medium Pressure U1.5 bar High Pressure U3.0 bar
Medium Pressure U2.0 bar High Pressure U4.0 bar
High Pressure U4.5 bar
PRODUCT DESCRIPTION
Electric motor driven twin ended peripheral pumps complete with an automatic control
system, consisting of flow switches, pressure switch and pressure vessel and electronic
controls.
APPLICATION
Monsoon Universal pumps are suitable for positive or negative head installation
conditions. The pumps are designed for whole house pressure boosting applications in
vented stored water systems. Inlet pressures to the pump and ambient temperatures
must not exceed the values given in the technical specifications.
This pump set must not be used for any other application without the
written consent of Stuart Turner Limited and in particular, must not be
connected directly to the mains water supply.
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 use of the appliance by a person responsible
for their safety.
Children should be supervised to ensure that they do not play with the
appliance.
WARNING - Washer/condenser dryers and condenser dryers.
The pump must not be used in the water supply line to a washer/
condenser drier or a condenser drier, which uses a constant flow of
cold water to aid the condenser drying process, as damage can occur
to the pump. If in doubt or for further information contact Stuart
Turner Ltd.
Please leave this instruction booklet with the pump as it contains
maintenance and safety information (Original Instructions)
INDEX . . . . . . . . . . . . . . . . . . . . . . . .Page No
Product Description . . . . . . . . . . . . . . . . . . . .1
Application . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Typical Installation . . . . . . . . . . . . . . . . . . . . .2
Pre-Installation Check . . . . . . . . . . . . . . . . . .2
Pump Location . . . . . . . . . . . . . . . . . . . . . . . .3
Pipework . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Pump Connections . . . . . . . . . . . . . . . . . . . . .6
INDEX . . . . . . . . . . . . . . . . . . . . . . . .Page No
Electrical Installation . . . . . . . . . . . . . . . . . . .10
Commissioning . . . . . . . . . . . . . . . . . . . . . . . .13
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . .15
Technical Specification . . . . . . . . . . . . . . . . . .18
Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Trouble Shooting Guide . . . . . . . . . . . . . . . . .19
Environment Protection . . . . . . . . . . . . . . . . .20

- 2 -
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.
TYPICAL INSTALLATION
(Universal Twin Pump System)
This diagram should be used for
schematic reference only
Item 1 = System service valves (not
supplied) should be fitted.
Item 2 = Flexible hoses complete with
integral pump isolating valves
(supplied).
Positive Head Negative Head
Fig. 1
The plumbing
installation
must comply with the following:
The Water Supply (Water Fittings)
Regulations 1999.
BS6700 and building regulations.
Be installed by a competent person.
If in doubt consult Stuart Turner Ltd.
1
2
1
STEP 1: PRE-INSTALLATION CHECK
The pressure vessel (Fig. 2) is factory fitted to the pump assembly.
To eliminate any risk that the vessel has lost its assembly torque and sealing ability
during transit, it must be checked prior to installation.
Tighten the vessel as shown to confirm a secure hand tight connection.
Note: Do not overtighten pressure vessel.
1
1
Pressure vessel
Fig. 2

- 3 -
STEP 2: PUMP LOCATION
WARNINGS:
Pump Location
If possible 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.
Care should be taken to protect pump from frost and freezing,
particularly when located in a loft installation.
The motor casing can become hot under normal operating conditions,
care should be taken to ensure it cannot be touched during operation.
The pump must not be located where the static pressure on the inlet
or outlet to the pump is greater than permitted. Should the
installation exceed these limits, contact Stuart Turner for further
advice.
The pump must be installed so that the following conditions are met:
Locate the pump in a dry, frost free position where it cannot be sprayed with water. It
should be positioned horizontally on its anti-vibration mounting feet and should not be
screwed down. It should be positioned as close to the water source as possible having a
minimum flooded suction head of 0.5 metres at all times.
The pump has a side mounted terminal box. Ensure the pump is mounted in a position
that allows easy access to the box if required.
Ensure the water flow is in the direction of the arrow that is marked on the flow switch
reed clamp (vertically upwards).
Before deciding where to position the unit, check to ensure the static inlet and outlet
heads of water above the pump (Figs 3 & 4), do not exceed the maximum permitted
limits.
Typical pump locations are in an airing cupboard, or inside a vanity unit with a small
purpose build dry and ventilated enclosure. The enclosure should have a minimum
clearance of 80 mm (3 ”) between the pump and housing on all sides. The enclosure
should be secure and access should only be available by the use of tools.
The anti-vibration mounting feet and flexible hoses which are supplied as standard, are
a precaution to reduce noise transmission, however care must be taken when mounting
the pump that any noise is not amplified through loose panels, pipework or other mounting
medium.
The preferred pump location is at floor level next to the hot water cylinder or a level that
is below the secondary tapping that feeds the pump. This will ensure the pump has
access to an air free water supply which is important for trouble free operation (Fig. 3).
Either end of the pump is suitable for hot or cold water.
Cont....

- 4 -
If it is not possible to locate the pump in the preferred area due to site limitations and it
is necessary to position the unit in the loft, or in a position above the secondary tapping
that feeds the pump, then there is an increased risk of air locks. This risk must be
eliminated.
The following measures are suggestions that may overcome the problem:
1) A "U" bend or downward loop in the supply pipe to the pump of 350 mm depth before
rising to the pump should ensure the cylinder vents its air up the expansion pipe not
up the pump feed (Fig. 4).
2) An alternative to the above would be the installation of an automatic air vent situated
at the top of a vertical pipe run directly connected to the pump discharge. This will
ensure any air collecting in the pump is automatically vented.
Note: If installed in loft
there must be a height of
200 mm from water surface
to the highest point of the
hot or cold inlet pipework at
all times to prevent air
locks.
Least Preferred Pump
Location (shaded area).
Pump located above the hot
cylinder can increase the
risk of air locks.
Preferred Pump Location
(shaded area). Pump at a level
below draw off tapping in
cylinder.
Negative head
Max. inlet head (see table 1) Min. inlet head 0.5 m
least preferred area
Max. outlet head (see table 1)
Fig. 4
200 mm min
350 mm
hot water
services
Negative head
Max. inlet head (see table 1) Min. inlet head 0.5 m
Preferred area
Max. outlet head (see table 1)
Fig. 3
hot water
services
Model Max. inlet
head
Max. outlet
head
U1.5
8 m 8 m
U2.0
U3.0
U4.0
12 m 12 m
U4.5
Table 1

- 5 -
STEP 3: PIPEWORK (General)
WARNINGS:
Ensure pipework to and from pump is independently supported to
prevent forces being transferred to inlet and outlet branches of pump.
Do not introduce solder flux to pumps, pump parts or hoses
manufactured from plastic. All solder joints should be completed and
flux residues removed prior to pump connection.
Do not allow contact with oil or cellulose based paints, paint thinners
or strippers, acid based descalents or aggressive cleaning agents.
Never operate pump with inlet and/or outlet isolating valves in the
closed position. Damage will occur!
Do not install a non-return valve, or devices
which contain non-return valves, in the
suction (inlet) pipework to the pump. The
pump must be free to vent to the supply
tanks at all times.
It must be ensured that the water storage capacity is sufficient to meet the flow rates
required by the pump and any other water using fittings and appliances, which may be
operated simultaneously.
As a rule of thumb: assuming a cold water temperature of 10°C and a hot water
temperature of 65°C.
A 6-minute shower using 10 litres/min will consume 40 litres of hot water and 20 litres
of cold. This means the total quantity of water used from the cold water storage tank
will be 60 litres (40 + 20).
A 10-minute shower using 15 litres/min will consume 100 litres of hot water and 50
litres of cold. This means the total quantity of water used from the cold water storage
tank will be 150 litres (100 + 50).
The pipework feeds to the storage tank should be of adequate size to ensure
replenishment rate of tank is sufficient to meet the needs of the pump.
Care should be taken in the design of pipework runs, to minimize the risk of air locks.
The pump should be supplied with balanced pressure hot and cold supplies.
To prevent loss of water pressure through pipework use 22 mm pipework throughout.
Any bend requirements should be achieved by hand drawing the tube or by the use of the
appropriate bend fittings. All pipework should be securely clipped.
The flexible hoses supplied incorporate integral isolating valves. These hoses should
be fitted in the suction and delivery pipework to enable easy access to the pump when
required.
Pipework Connections (Cold)
The pump must be supplied with a dedicated feed direct from the cold water
storage tank.
The supply must be air free and connection of the feed pipe to the tank should be via a
tank connector, positioned at a slightly lower level (25 mm minimum) than the feed pipe to
the hot water cylinder.

- 6 -
Pipework Connections (Connection between pump and system outlet)
This should run as far as possible in 22 mm copper tube. Pipework should only be
reduced to 15 mm copper if necessary when entering the terminal fittings. By this method
the maximum performance of the pump will be maintained.
STEP 4: PUMP CONNECTIONS (Release and connection of push-in connectors)
WARNINGS:
Do not use stainless steel, chrome or nickel plated pipe with the
flexible hose push-in plumbing connections.
Do not introduce solder flux into the joint or surrounding area as
connectors will be attacked and may fail.
All solder joints should be completed and flux residues removed
before final connection to push-in connections, on the flexible hose.
Do not allow contact with oil or cellulose based paints, paint thinners
or strippers, acid based descalents or aggressive cleaning agents.
Never operate pump with inlet and/or outlet isolating valves in the
closed position. Damage will occur!
The pump is supplied with flexible hoses for connection to inlet and outlet pipework. It
is recommended that only the Stuart Turner hoses supplied are used for making these
connections.
Pipework Connections (Hot)
When a hot water cylinder or storage tank is used, ensure the pipework size from the
cold water storage to the hot water storage is of adequate size and a minimum of 22 mm.
The pump must be supplied with a dedicated feed direct from the hot water
cylinder or storage tank.
The supply must be air free and connection to the cylinder can be made by one of the
methods shown in Fig. 5.
When the method of connection is to be made via the expansion pipe, the cold water
storage cistern should be at least 1 metre above the top of the hot water cylinder.
Off expansion
pipe with rising
28 mm offset
reducing to
22 mm pipework
to pump and
expansion pipe.
Off expansion
pipe with rising
22 mm offset
and 22 mm
pipework to
pump.
Off vertical
expansion pipe
with 22 mm
pipework to
pump.
Factory installed G ¾
secondary tapping
with 22 mm pipework
to pump.
or
Site installed G ¾
Essex Flange with
22 mm pipework to
pump.
Warix Flange with
22 mm pipework to
pump.
Fig. 5

- 7 -
Hose to pipework
1. The hoses are fitted with plastic push-in connectors, which must only be connected
with the following:
a) 22 mm diameter copper pipe to BS EN 1057 - R250 (half hard) - Table 3.
b) 22 mm plastic pipe to BS 7291 part 1 and part 2 (Table 1), or part 3 (Table 1) plus
internal support sleeve*.
* The internal bore of the plastic pipe must be supported against collapse with the
pipe manufacturers recommended support sleeve (pipe insert).
c) Appropriate plumbing fittings that are compatible and will provide a water tight
connection.
Ensure the pipe is free from all score marks and deformities in the area of the
insertion depth (Fig. 7) and cut the pipe square removing all burrs and sharp
edges to prevent damage to the sealing 'O'-ring.
Hose to pump
The pump inlet and outlet ports have factory assembled fittings which are specifically
designed for connection to the G¾ female running nuts on the flexible hoses. The hose
end is fitted with a rubber sealing washer which is held captive within the nut assembly.
Locate the hose into position and screw the nut fully onto the fitting by hand. Finally nip
tight with a spanner (4/5 Nm) for a water tight seal (do not overtighten).
Cont....
Rubber sealing washer
(captive in nut assembly)
Fig. 6
Flexible hose
G¾ running nut
assembly
Port fitting
Note: When tightening or loosening the
hose nut assembly, the anti-rotation
flats provided on the inlet and outlet
fittings should be used for placement of
a second spanner as shown. This is to
prevent complete assembly rotation.
It may be necessary to partially rotate
the reed switch clamp assembly on the
outlet fitting to avoid damage during
placement of the second spanner.
Reed
switch
clamp
assembly
Anti-rotation flats
28 mm AF
29 mm AF

- 8 -
2. Prior to inserting pipe into fitting mark the insertion depth on the wall of the pipe with
a soft pencil at a distance of 33 mm from the end to be inserted.
3. Check in the mouth of the fitting that ‘O’-ring, nylon washer and collet are in
position.
4. Push pipe firmly into fitting, until pencil mark is level with the top of the collet and the
pipe stop resistance is felt. Pull on pipe to check it is secure and correctly fitted.
5. To break the joint, push pipe firmly into fitting, hold collet down and gently
remove pipe. If the system has been filled with water care should be taken to isolate
pump and towels used to absorb spilled water.
If you have any concern either about using push-in fittings or should the joint leak on
final test isolate the water supplies and contact Pump Assist on 0844 98 000 97.
Fig. 8
Body
Collet
Washer
‘O’-Ring
Pipe Stop
Isolating Valve
22 mm Pipe
Pencil
mark
Insert depth
33 mm
Fig. 7

- 9 -
The pump should not be screwed down, ensure anti-vibration feet and flex hoses
are used.
Never operate pump with inlet and/or outlet isolating valves in the closed
position. Damage will occur!
Pump Connections (General)
Pump body.
Flow switch.
Anti-vibration foot. Fig. 9
Vent plug.
Isolating valve.
Delivery supply to shower/bathroom
fitted with G¾ male threaded pump
connection.
G¾ running nut with captive sealing
washer.
Flexible hose.
22 mm copper outlet
pipework.
22 mm flexible pipes
with push-in
connections, ensure
that connection is fully
pushed home into hose
end fitting and that hoses are kept as
straight as possible.
In the case of horizontal feeds use a
22 mm compatible stem elbow (not
supplied). Do not bend the hose
more than 30° as they may become
damaged, transmit noise or leak.
22 mm copper inlet
pipework
Suction supply
from tank with
push-in plumbing
connection.
Integral pump isolating
valve shown in ‘OFF’
position.
Integral pump isolating valve
shown in ‘ON’ position.
Flexible hose.
Inlet strainer housed
in this location (see
maintenance section).
Suction supply from tank
with G¾ male threaded
pump connection.
G¾ running nut with captive
sealing washer.
30°
Max.
permitted
flexible
hose
bend. Pressure switch.
Do not kink or twist
the hose.

- 10 -
Typical Low Level Installation
In certain installations it may be necessary to install a 90° bend on the inlet or outlet
connections of the pump before the flexible hose to accommodate a low level installation.
Below are some preferred connection options. All connections seal on the pump body
using a fibre or rubber sealing washer. Tap connector fittings should be used which must
be of an appropriate pressure and temperature rating.
It is essential when using any of the fittings shown below, that a correct water tight seal
is obtained between the pump body and selected fitting and also the flexible hose and
selected fitting. If in doubt contact the fitting manufacturer and confirm compatibility with
the connection to be sealed.
Carefully check connections and pipework for leaks whilst pump running and stationary
before leaving the installation unattended.
STEP 5 ELECTRICAL INSTALLATION
WARNINGS:
The electrical installation must be carried out in accordance with the
current national electrical regulations and installed by a competent
person.
In the interests of electrical safety a 30 mA residual current device
(R.C.D.) should be installed in the supply circuit. This may be part of
a consumer unit or a separate unit.
Before starting work on the electrical supply ensure power supply is
isolated.
This appliance must be earthed.
The motor and wiring must not be exposed to water.
Do 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.
G¾ female x 22 mm
elbow tap connector.
22 mm compression to
G¾ male. G¾ female flexible hose
(supplied in kit).
Fibre washer.
22 mm copper pipe.
22 mm
copper
pipe
G¾ female x 22 mm
swivel tap connector
with rubber sealing
washer.
G¾ female x 22 mm
tap connector with
rubber sealing washer.
22 mm stem elbow.
G¾ female flexible hose
(supplied in kit).
22 mm compression to
G¾ male.
G¾ female x 22 mm
tap connector.
Fibre washer.
G¾ female
flexible hose
(supplied in
kit).
22 mm to G¾
male.
Fig. 10
Sealing washer
(sometimes captured in
fitting)
22 mm
elbow.

- 11 -
The motor fitted to this pump is suitable for a 230/1/50Hz supply. It is thermally
protected by an integral auto resetting thermotrip for your safety and rated for the duty
listed in the technical specification section.
Electrical Connection
The motor is provided with a factory fitted supply cord. This must be permanently
connected to the fixed wiring of the mains supply. Means for disconnection must be
incorporated in the fixed wiring in accordance with the wiring rules.
A suitable method of connection would be via a double pole switched, fused connection
unit complying with BS 1363-4, protected with a fuse (see fuse section).
The connection unit should be mounted in an easily accessible position and should be
labelled if confusion is possible, to allow easy identification of the pump isolating switch.
Earthing
This appliance must be earthed via the supply cord, which must be correctly connected
to the earth point located in the terminal box.
Copper or metallic pipework must have supplementary earth bonding where the
continuity has been broken by flexible hoses or plastic components. Adjacent suction and
delivery pipes should be fitted with earthing clamps to BS 951 and connected with
earthing wire size 4 mm² (Fig. 11). A standard kit is available from Stuart Turner (Part No.
17044).
Certain installations may require additional earthing arrangements such as equipotential
bonding. Reference should be made to the relevant regulations concerning this subject to
ensure compliance.
Wiring Of Connection Unit
WARNING: This appliance must be earthed.
The wires in the mains lead (supply cord) are coloured in accordance with the following
code:
Green and Yellow: Earth Blue: Neutral Brown: Live
As the colours of the wires in the mains lead of this appliance may not correspond with
the coloured markings identifying the terminals in your connection unit proceed as follows:
The wire which is coloured green and yellow must be connected to the terminal in the
connection unit which is marked with the letter E or by the earth symbol: or coloured
green or green and yellow.
The wire which is coloured blue must be connected to the terminal which is marked with
the letter N or coloured black.
The wire which is coloured brown must be connected to the terminal which is marked
with the letter L or coloured red.
Diagram of
earth continuity
connections
Fig. 11

- 12 -
Wiring Diagram (Schematic)
The 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 any disturbance of this internal wiring is
avoided and the factory routing and securing of all internal wiring is
always maintained.
Fuses
The following fuse size should be used with the appropriate pump.
Supply Cord Replacement
The 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.
If 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.
On disassembly note the cord retention and routing system. Re-assemble to the same
pattern.
For information on cable connection consult the wiring diagram and cable gland fitting
instructions.
MAIN WINDING
THERMOTRIP CAPACITOR
START WINDING
FLOWSWITCH
REED (S3)
LINK WIRE (BLUE)
BROWN
BLACK
GREEN / YELLOW
BLUE
BROWN L
S2 S3 S3 S2
E
N230 VAC/1PH/50Hz
SUPPLY
BLUE
NA MNL
S1 S1
FLOWSWITCH
REED (S2)
PRESSURE
SWITCH (S1)
Fig. 12
Model Fuse Size (AMPS)
U4.0 bar Twin
13
U4.5 bar Twin
All other models 5

Cable Gland Fitting Instructions
- 13 -
To enable correct assembly of the cable gland the 'O'-ring (Fig. 13 item 1) must be
placed over the cable before the clamping insert (Fig. 13 item 2) can be tightened.
Note: Cable diameter range:- 6.5 mm to 9.5 mm.
Supply Cord Extension
The pumps are fitted with a supply cord to the following specification:-
All models . . . . . . . . . . . . . . . . . .HO5VV-F3 G 0.75 mm² - 6 Amp rated cable.
If the supply cord is to be extended, a cord of the same specification should be used.
Any connections or junction boxes used should be specifically suited for the application
and installed in accordance with the manufacturers instructions.
STEP 6 COMMISSIONING
WARNINGS:
The motor casing can become hot under normal operating conditions,
care should be taken to ensure it cannot be touched during operation.
Do not run pump without guards and terminal box lid correctly fitted.
The pump chamber must be full of water at all times. Seal damage will
result if the pump runs dry.
1. System Flushing
This pump incorporates push-in connectors and plastic components that
must not come into contact with solder flux, acid-based descalents or
aggressive cleaning agents. The pipework system should be flushed out
prior to the pump being connected to ensure any contaminants/chemical
residues and foreign bodies are removed from elsewhere in the system.
2. Water Supply
Always ensure that water storage capacity is adequate to meet the demand.
Ensure the pump chamber is full of water before starting the pump. Failure
to do this could result in seal damage. To ensure dry running does not
occur the pump must be primed as described in priming section. Do not
run pump dry.
Fig. 13
1
2

- 14 -
3. Priming
WARNING
Never operate pump with inlet and/or outlet isolating valves in the
closed position. Damage will occur!
The chambers must be primed (filled with water) before starting.
This is achieved as follows.
a) Turn off the pump inlet isolating valves 1 & 2 and
pump outlet isolating valves 3 & 4.
b) Turn on water supply to pumps from the system
service valves.
c) Open pump inlet isolating valve (1).
d) Place a towel under priming plug (Fig. 14) to absorb
any spillage.
e) Loosen priming plug on shuttle valve assembly (Fig. 14).
f) Wait until an unrestricted and even flow of water is seen to flow from the priming
plug location hole. This may take up to 30 seconds.
g) Re-seal priming plug by nipping tight to 1.5 Nm.
h) Close pump inlet isolating valve (1) and repeat process with pump inlet isolating
valve (2).
i) Now both pump chambers are full of water.
j) Open both pump inlet and outlet isolating valves. The pump is now ready to start.
On Off
Fig. 14
Priming Plug
1
2
4
3

- 15 -
4. Starting The Pump
a) Ensure all outlets are closed, turn power supply ‘on’ - pump will start, pressurise
the system then stop.
b) Open and close all outlets in turn associated with the pump, (including w/c
systems) allowing water to flow from each outlet until all air is purged. As each
outlet is opened and closed, the pump will start and stop respectively.
Note: After closing the outlet there will be a small delay time before the pump
stops, which is normal.
Any tap or control valve within the system when opened and closed will now turn
the pump on/off. Providing this is the case the system is now operating correctly.
c) Carefully check pump and pipework for leaks whilst pump running and stationary
before leaving the installation unattended.
For Further Technical Support
Phone the Stuart Turner Pump Assist team on 0844 98 000 97. Our staff are trained to
help and advise you over the phone or arrange for a service engineer to call.
MAINTENANCE
WARNINGS:
Care should be taken to protect pump from frost and freezing,
particularly when located in a loft installation.
Pump Location
If possible 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.
1. No routine maintenance is required, but provision should be
made for easy access to the pump to allow repairs due to
normal wear and tear.
2. Disconnect electrical supply before working on pump.
3. Turn off water supplies to the pump and release pressure by opening water outlets
before attempting maintenance.
4. The inlet strainers may require periodical cleaning. The frequency of this operation is
dependent upon installation conditions.
The strainer is located in the inlet assembly of the pump casing (see pump
connection section) and is removed as follows:-
a) Isolate pump electrically.
b) Release all system pressure.
c) Isolate hot and cold water supplies via the integral pump isolating valve located in
the flexible hoses and release hose nuts connected to the pump (see pump
connections section).
d) Remove M4 screws (2 off) from inlet assembly, lift brass inlet fitting (with ‘O’-ring)
and clamp away from pump casing (Fig. 15).
e) Remove strainer with long nose pliers noting location lug position upon removal
(Fig. 15) and clean thoroughly.
f) Refit strainer taking care to position lug in body inlet port location slot (Fig. 15)
and re-assemble pipework. Tighten M4 clamp screws to 1.5 Nm torque.
g) After maintenance is completed refer to commissioning section for instructions on
re-starting pump.

- 16 -
5. The pressure vessel air pre-charge does not require routine maintenance. Should
ever the need arise for the vessel to have its air pre-charge checked or replenished, it
should be carried out as follows: -
a) Isolate pump electrically.
b) Isolate hot and cold water supplies via the integral pump isolating valve located in
the flexible hoses (see pump connections section).
c) Release system water pressure by opening a system outlet (tap).
d) Check air pre-charge at Schrader valve (Fig. 16) using a tyre pressure gauge.
Cont....
Fig. 15
M4 screws
Manifold clamp
Strainer
Inlet fitting
‘O’-ring
Location detail
Inlet port
Model Vessel Pressure
kPa bar psi
U1.5 bar Twin
90 0.9 13.0
U2.0 bar Twin
U3.0 bar Twin
U4.0 bar Twin 130 1.3 18.5
U4.5 bar Twin

e) Replenish air charge if required by injecting air into the vessel via the Schrader
valve using a car or bicycle pump, ensuring a system outlet valve (tap) remains
open during this procedure to allow the vessel to exhaust any excess water.
f) Close all system taps, open hot and cold inlet pump isolating valves, turn on
electrical power.
g) After maintenance is completed refer to commissioning section for instructions on
re-starting pump.
6. As water is heated scale deposits are released in areas of hard water (usually south
of a line between the Wash and Bristol Channel), scale can cause the mechanical
seal to stick if left without use for long periods. We recommend the pump is run for
at least 5 minutes every four weeks to "exercise" all working parts. Run on cool
water. See technical specification for note on water temperature. This particularly
applies to guest bathrooms used infrequently.
Cleaners, Disinfectants and Descalents
On installations where chemical disinfectants or descalents are periodically
used, the compatibility of the chemical solution regarding the pump must be
considered.
Acid based descalents and aggressive cleaning agents must not come into
contact with the pump. The pump must be removed from the system prior to
the use of these products. The system should be flushed to remove all
chemicals before the pump is re-connected.
If in any doubt as to the suitability of the chemical solutions, please contact
our Pump Assist helpline.
- 17 -
Cont....
Schrader valve
Pressure vessel
Fig. 16

- 18 -
TECHNICAL SPECIFICATION
Stuart Turner reserve the right to amend the specification in line with its policy of
continuous development of its products.
Note: For information on other voltages/frequencies which are not shown, consult any
supplementary instruction sheet supplied, or the rating label attached to the
pump.
*Note: Max working pressure is the maximum pressure that can be applied to the
pump internal casing under any installation conditions.
**Note: In normal circumstances the temperature of stored water should never exceed
65°C. A stored water temperature of 60°C is considered sufficient to meet all
normal requirements and will minimize deposition of scale in hard water areas.
Maximum permissible water temperature 65°C.
Model U1.5 bar
Twin
U2.0 bar
Twin
U3.0 bar
Twin
U4.0 bar
Twin
U4.5 bar
Twin
Electrical
Power supply
Volts/phase frequency
Motor enclosure
Type of motor
Max. power consumption
Full load current
Rating
Max. no. starts per hour
230/1/50
IPX4
Induction
355 Watts
1.5 Amps
Continuous
(S1) @ 9 l/min
& above
(Both ends
pumping)
60
230/1/50
IPX4
Induction
435 Watts
1.9 Amps
Continuous
(S1) @ 9 l/min
& above
(Both ends
pumping)
60
230/1/50
IPX4
Induction
655 Watts
2.9 Amps
Continuous
(S1) @ 9 l/min
& above
(Both ends
pumping)
60
230/1/50
IPX4
Induction
875 Watts
3.9 Amps
Continuous
(S1) @ 9 l/min
& above
(Both ends
pumping)
60
230/1/50
IPX4
Induction
1135 Watts
5.1 Amps
Continuous
(S1) @ 9 l/min
& above
(Both ends
pumping)
60
Mechanical
Max inlet head
Max head (closed valve)
Max working pressure*
Max ambient air temperature
Pressure vessel air pre-charge
Max water temperature**
Min water temperature
8 metres
15 metres
600 kPa
(6.0 bar)
40°C
90 kPa (0.9
bar) (13 psi)
65°C
4°C
8 metres
20 metres
600 kPa
(6.0 bar)
40°C
90 kPa (0.9
bar) (13 psi)
65°C
4°C
8 metres
30 metres
600 kPa
(6.0 bar)
40°C
90 kPa (0.9
bar) (13 psi)
65°C
4°C
12 metres
40 metres
600 kPa
(6.0 bar)
40°C
130 kPa (1.3
bar) (18.5 psi)
65°C
4°C
12 metres
45 metres
600 kPa
(6.0 bar)
40°C
130 kPa (1.3
bar) (18.5 psi)
65°C
4°C
Dimensions
Length
Width
Height (excluding flexible hoses)
Gross weight (packed)
265 mm
162 mm
243 mm
9.2 Kg
265 mm
162 mm
243 mm
9.2 Kg
265 mm
162 mm
243 mm
10.4 Kg
300 mm
162 mm
243 mm
12.5 Kg
310 mm
162 mm
243 mm
13.3 Kg

- 19 -
NOISE
The equivalent continuous A-weighted sound pressure level at a distance of 1 metre
from the pump does not exceed 70 dB(A).
TROUBLE SHOOTING GUIDE
Symptoms Probable Cause Recommended Action
Pump will not start. Electrical supply.
Faulty pressure switch.
Faulty reed switch or PCB.
Recommended static
inlet/outlet heads exceeded.
Internal motor thermotrip
activated.
Check wiring connections.
Check all switches are ‘on’.
Check fuse (see fuse section).
Check circuit breaker is set.
Turn off power.
Release system water pressure.
Turn on power, pump should start.
If NOT refer to circuit test in Fig. 17 to confirm PCB
operating correctly.
Refer to circuit test as detailed in Fig. 17.
Re-position pump (see pump location section).
Wait for thermotrip to auto-reset and check that duty point
and run time is within specification (see technical
specification).
No hot water. Air locked water feed.
Boiler is switched off.
All hot water has been used.
Faulty thermostatic mixer
valve.
Vent hot water pump of air.
Check cold feed to hot water cylinder.
Check water level in cold water tank and that all
stopcocks and isolating valves are open.
Check boiler is switched ‘on’.
Check cylinder thermostat.
Check immersion heater.
Check cylinder contains hot water.
Check tank volume is adequate.
Consult makers instructions.
Pump starts when outlets
are off.
or
Pump cycles (hunts) on/off
frequently.
Leak in system.
Low pre-charge pressure in
pressure vessel.
Debris under non-return
valve sealing face.
Check tap washers, w/c valve washers, pipe joints.
Check pre-charge pressure in pressure vessel
(see maintenance section).
Run at full flow to try and flush away debris or remove,
clean or replace non-return valve.
Pump runs on when all
terminal outlets are closed.
Leak in system.
Reed clamp out of position.
Faulty reed switch, P.C.B or
pressure switch.
Jammed flow switch.
Check tap washers, w/c valve washers, pipe joints.
Ensure reed clamp is fitted correctly in location groove
(Fig. 17).
If pump continues to run, this indicates a closed circuit in
either the flow switch reed, pressure switch or P.C.B. in
the terminal box, these should be checked electrically.
Isolate the pump electrically and hydraulically and remove
brass housing that contains the float. Check float for free
movement.
Reduced flow/performance. Blocked inlet strainers.
Blocked shower head spray
plate.
Blocked pipework or pump.
Clean inlet strainers (see maintenance section).
Clean in accordance with manufacturers instructions.
Isolate pump electrically and hydraulically, locate blockage
and remove.

- 20 -
Flow Switch Circuit Test
1. First confirm visually that the flow switch reed clamps have not been dislodged during
handling or installation. The clamps must be fully located within their flow switch
body groove as shown.
2. To carry out the following test you will need to obtain a magnet, a typical fridge
magnet is suitable.
3. Ensure the power supply is switched on.
4. Position the magnet directly in front of the reed clamp as shown. If pump does not
start, then slowly move the magnet up and down to a position that exceeds the extent
of the reed clamp. The pump should instantaneously start at some point during this
extent of movement. If this does not happen, this indicates a possible fault with the
reed switch or the P.C.B which is located within the terminal box. These should be
checked electrically. Consult Stuart Turner for further instructions.
ENVIRONMENT PROTECTION
Your appliance contains valuable materials which can be recovered or recycled.
At the end of the products’ useful life, please leave it at an appropriate local civic waste
collection point.
Body
Reed Clamp
Magnet
Groove
Fig. 17