Mira Combiforce 415 User manual

PRESSURE BALANCED
User Guide
Installation and
SHOWER CONTROL
THESEINSTRUCTIONSARETOBELEFTWITHTHEUSER

2
py
Contents
Section Page
1.......Introduction ................................................................... 3
2.......ImportantSafetyInformation ........................................... 4
3.......Pack Contents Checklist.................................................. 5
4.......Dimensions ................................................................... 7
5.......Specifications ................................................................... 8
6.......InstallationRequirements ................................................ 9
7.......Installation ................................................................. 14
8.......Commissioning............................................................... 29
9.......Operation......................................................................... 33
10.....Fault Diagnosis ............................................................... 35
11.....Maintenance.................................................................... 41
12.....Spare Parts...................................................................... 46
13.....Accessories .................................................................... 50
Guarantee, Customer Care Policy, and How to contact us .......
.........................................................................................Back cover

3
Thank you for purchasing a quality Mira product. To enjoy the full potential of your new
product, please take time to read this guide thoroughly, having done so, keep it handy for
future reference.
The Mira CombiForce 415 is a pressure balanced shower control which maintains a
constant outlettemperatureirrespective of changes in inletpressuresas long as the
inletwater temperatures remain the same. It is not a thermostatic shower control and
does not sense supply temperature variations. Therefore, inlet water temperatures
especially the hot, should remain relatively constant.
The Mira CombiForce 415 can be installed with the following packages:
- Fully modulating multipoint gas water heaters.
- Fully modulating combination boilers.
- Unvented mains pressure systems.
- Mains pressurised, instantaneous hot water heated from thermal store, systems.
- Pumped systems.
Showering temperature is adjusted by the shower control. The flow rate is determined by
the supply pressures available at the inlets, and the output rating of the heater appliance.
Shower controls covered by this guide:
Mira CombiForce 415
Surface mounted pressure balanced shower control for connection to exposedpipework,
for high pressure applications (1.0 – 5.0 bar). Available in white/chrome, white/light
golden or all chrome finish.
Mira CombiForce 415B
Built-in shower control for connection to concealed pipework, for high pressure
applications (1.0 – 5.0 bar). Available in white, white/chrome, white/light golden or all
chrome finish.
1Introduction
Section
If you experience any difficulty with the installation or operation of your new
shower control, then please refer to Section 10, "Fault Diagnosis", before
contacting Kohler Mira Limited. Our telephone and fax numbers can be found on
the back cover of this guide.

4
Important Safety Information1Section
Section
2Important Safety Information
Warning!
1. Products manufactured by us are safe and without risk provided they are
installed, used and maintained in good working order in accordance with our
instructions and recommendations.
Caution!
1. Read all of these instructions.
2. Retain this guide for later use.
3. Pass on this guide in the event of change of ownership of the installation site.
4. Follow all warnings, cautions and instructions contained in this guide.
5. The plumbing installation must comply with the requirements of UK Water
Regulations/Byelaws (Scotland), Building Regulations or any particular
regulations and practices, specified by the local water supplier. The
installation should be carried out by a plumber or contractor who is
registered or is a member of an association such as:
- Institute of Plumbing (IOP), throughout the UK.
- National Association of Plumbing, Heating and Mechanical Services
- Contractors (NAPH & MSC), England and Wales.
- Scottish and Northern Ireland Plumbing Employers’ Federation
(SNIPEF), Scotland and Northern Ireland.
6. Anyone who may have difficulty understanding or operating the controls of any
shower should be attended whilst showering. Particular consideration should
be given to the young, the elderly, the infirm, or anyone inexperienced in the
correct operation of the controls.

5
1 x CombiForce 415 Shower Control ❏2 x Pipe Concealing Plates ❏
2 x 1/2" BSP Inlet Connector Nipples ❏2 x Fibre Gaskets ❏2 x Olives ❏
2 x Compression Nuts ❏1 x Outlet Nipple ❏1 x 2.5 mm A/F
Hexagon Wrench ❏
2 x 13/4" Fixing Screws ❏2 x Wallplugs ❏1 x ‘O’ Seal ❏
❏Tick the appropriate boxes to familiarise yourself with the part names and to confirm
that the parts are included.
1. Mira CombiForce 415 Surface Mounted Shower Control
3Pack Contents Checklist
Section
✔

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2. Mira CombiForce 415B Built-in Shower Control
3. Documentation
1 x Installation and User Guide ❏
1 x Customer Support Brochure ❏
1 x Wall Mounting Bracket ❏
1 x CombiForce 415 Shower Control
with Building-in Shroud
❏1 x Concealing Plate,
Circular Mounting Bracket
and Foam Seal ❏
3 x Compression Nuts ❏
3 x Olives ❏
2 x M4 x 30 mm Screws ❏
2 x No. 8 x 11/4" Fixing Screws ❏
2 x Wallplugs ❏
2 x M4 x 16 mm Screws ❏
1 x 2.5 mm A/F
Hexagon Wrench ❏
1 x Outlet Nipple ❏
1 x ‘O’ Seal ❏
1 x Control
Knob Cap
❏

7
Dimensions
Section
4
All dimensions are nominal and in millimetres
Mira CombiForce 415B
Mira CombiForce 415
Top Inlet
(Falling)
Supplies
Bottom Inlet
(Rising)
Supplies
153
Ø56
Back Inlet
Supplies
Ø92
35
35
132 A/F 135
Ø163
188.5 135
92 A/F Ø76
57 to 74

8
SPECIFICATIONS
5Specifications
Section
MiraCombiForce415and415B
PressureRange
Minimum maintained pressure: 1 bar.
Maximum maintained pressure: 5 bar.
Maximum static pressure: 10 bar.
Note! For optimum performance, the initial supply pressures should be nominally
equal.
Temperatures
Hot and cold water supply temperatures MUST remain relatively constant.
Maximum hot water temperature: 85°C.
Ideally the hot water temperature should never exceed 65°C. A water temperature of
60°C is considered sufficient to meet all normal requirements and will minimize the
deposition of scale in hard water areas.
Connections
Inlet
15 mm Compression or 1/2'' BSP male (CombiForce 415).
15 mm Compression (CombiForce415B).
Outlet
1/2'' BSP male (CombiForce 415).
15 mm Compression or 1/2'' BSP male (CombiForce 415B).

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Float operated valve
Stop or servicing valve
Shower control
Warning or overflow pipe
Drop tight pressure reducing
valve (PRV)
Key to symbols appearing throughout this guide.
1. Layout and sizing of pipework must be such that when other services are used,
pressures at the shower control inlets do not fall below the recommended minimum
(1bar). The pressure balancing performance is impaired below 1 bar. When fitted
with some heater appliances the minimum maintained pressure may be above 1
bar, refer to the section Commissioning: “Multipoint gas water heaters” or
“Combination boilers”.
2. The Mira CombiForce 415 is not suitable for installation as part of a gravity-fed
plumbing system (i.e. in conjunction with a hot water cylinder and cold water
storage cistern), unless used in conjunction with an inlet pump producing a
maintained pressure of at least 1 bar.
3. When used with a fullymodulatingmultipoint or combination boiler above5bar
maintainedpressure, a pressure reducing valve will be necessary. For information
on measuring system pressures refer to InstallationRequirements:"Measuring
SystemPressures". For further information on pressure reducing valves consult
your local plumbing stockist.
4. Supply pipes MUST be flushed to clear debris before connecting the shower
control.
5. Conveniently situated isolating valves MUST be fitted for servicing purposes.
6. If the shower control is to be used with a fully modulating multipoint water
heater, fully modulating combination boiler, thermal store or unvented system
an expansion vessel must be fitted to accommodate the expansion of water in
the domestic hot water supply (this may already be part of the system, check
the details on the boiler/heater or contact the boiler/heater manufacturer).
7. No form of outlet flow control should be fitted, only Mira recommended fittings
should be used in the outlet pipework.
6Installation Requirements
Section
Twin impeller inlet pump
Tempering valve
Mini expansion vessel
Non-return Valve

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TypicalSuitableInstallations
1. Instantaneous multipoint water heaters and combination boilers
The shower MUSTbe installed with a multipoint gas water heater or combination
boiler of a fullymodulatingdesign(i.e. where the water draw-off rate indirectly
controls the gas flow rate to the burner).
An expansion vessel MUST be fitted (and regularly maintained) if any form of
backflow prevention device is fitted, e.g. non-return valve, PRV. This will ensure
that excess expansion or pulse pressures do not damage the product or the
plumbing system. The expansion vessel may already be fitted within the boiler
(check with the manufacturer) and is in addition to the normally larger central
heating expansion vessel.
Figure 1
HOTCOLD

11
HOT
COLD
Combined outlet PRV
with internal non-return valves
- Expansion vessel required.
Cold takeoff after PRV
- Expansion pressure taken up by
unvented cylinder expansion vessel.
Reduced
pressure to
unvented
cylinder
High
Inlet
Pressure
Reduced
pressure to
cold inlet of
shower
Reduced
pressure to
unvented
cylinder
High
Inlet
Pressure
Reduced
pressure to
cold inlet of
shower
Expansion
Vessel
Safety devices
not shown
for clarity
2. Unventedmainspressureshowers
The shower can be installed with an unvented, stored hot water cylinder. Only
a "competent person" as defined by the Building Regulations may fit this type
of system.
For packages with no cold water take off after the appliance reducing valve, it
will be necessary to fit an additional drop tight pressure reducing valve when
the mains pressure is over 5 bar. The drop tight pressure reducing valve must
be set at the same value as the unvented package pressure reducing valve.
Note! An expansion vessel MUST be fitted (and regularly maintained) if any
form of backflow prevention device is fitted, e.g. non-return valve, PRV. This
will ensure that excess expansion or pulse pressures do not damage the product
or the plumbing system.
Figure 2

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3. Mains pressurised instantaneous hot water shower, heated from a
thermal store
Packages of this type, fitted with a tempering valve can be used.
A drop tight pressure reducing valve MUST be fitted if the supply pressures
exceed 5 bar maintained.
An expansion vessel MUST be fitted (and regularly maintained) if any form of
backflow prevention device is fitted, e.g. non-return valve, PRV. This will
ensure that excess expansion or pulse pressures do not damage the product
or the plumbing system. The expansion vessel may already be fitted externally
or internally within the thermal store (check with thermal store manufacturer).
COLD HOT
Figure 3
4. Pumped showers (inlet pumps)
The shower can be installed with an inlet pump (twin impeller). The pump
MUST be located on the floor next to the hot water cylinder. The hot water
cylinder/vent pipes must be arranged as shown to achieve air separation.
90 °
30 to 60 °
Air Separation
Figure 4

13
MeasuringSystemPressures
1. General
It is important that the system pressures are within the range specified for the
Mira CombiForce 415 (refer to the Specifications section).
If the system pressure is not known then the system pressure MUST be
measured as explained in this section.
Pressures are those present at the inlet to the appliance either whilst running
(maintained) or in the off state (static). Nearby hot and cold taps connected to
the same proposed feed pipes as the appliance can be used to measure the
static pressure. No other fitting or appliance should be in use at this time.
Water pressures vary throughout the day, therefore you must ensure that water
pressures do not drop below or exceed the minimum/maximum required (refer
to the Specifications section).
2. To measure static pressure (Refer to Figure 5)
With the pressure testing device firmly connected to a tap drawing from one of
the proposed feed pipes and the outlet from the device in the off position, the
tap is turned on and the static pressure noted.
3. To measure maintained pressure (Refer to Figure 5)
The pressure testing device is connected as above, the taps turned on and the
outlet from the device opened until a flow of around 5 l/min is obtained (this is
easily done by timing the flow into a calibrated container). The maintained
pressure which can be expected when the shower is in operation can then be
read. This should be carried out on the hot and cold supply.
4. To measure pressure drop
Pressure drop results from another fitting being turned on when the shower is
in use. Having checked the maintained pressure as in 3.3. and with the device
still discharging at approximately 5 l/min, turn on a second draw-off from the
same feed pipe. This new reading will show the pressure drop from 3.3. and
should be above the minimum maintained pressure recommended by the
manufacturer.
Pressure
Gauge
Hose Type
Tap Connector
Ball Valve
PressureTestingDevice
Figure 5

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1. Before you decide on the final position
of your shower control, please bear in
mind the following:
- Decide on a suitable position for
the shower control. The position
of the shower control and the
shower fittings must provide a
minimum gap of 25 mm between
the spill-over level of the shower
tray/bath and the handset. This
is to prevent backsiphonage.
- Determine whether the hot or
cold water services will be
connected to the shower control
from the bottom (rising) or from
the top (falling).
7Installation
Section
Falling Supplies
Rising Supplies
25 mm
Minimum
Spill-over Level
Hose Retaining
Ring
Mira CombiForce 415 Surface Mounted Shower Control
Rising or Falling Inlet Supplies
Note! The Mira CombiForce 415 is supplied with inlet connections hot left, cold right
and bottom outlet as standard. For installations with reversed hot and cold supplies
complete the installation and refer to the section Installation: "Reversed Inlet
Supplies".

15
Backplate
Grub
Screws
2. Remove the backplate by releasing,
anticlockwise, the two recessed grub
screws which retain the backplate
against the brass shower control body,
using the 2.5 mm A/F hexagon wrench
(supplied).
3. Mark the final position of the shower
control on the finished wall surface
using the backplate as a template.
Mark the position of the two holes on the
backplate. Ensure the holes are
vertically aligned.
WARNING! Ensure there are no buried
cables or pipes in the wall before drilling.
4. Drill the two marked fixing holes and fit
the wallplugs provided. Secure the
backplate to the wall with the two No. 8
x 13/4"fixing screws.
Note!Screws with larger heads will foul
the shower control body.
5. Thoroughly flush the incoming hot
and cold water supplies before
connecting the shower control.
6. Release, anticlockwise, the two grub
screws that retain the inlet elbows,
using the 2.5 mm A/F hexagon wrench
(supplied). Ensurethatthe‘O’sealis
correctly located on the smaller
diametershoulderofthebrassinlet
connector,andnotinthe‘V’groove.
'V' Groove
'O' Seal
Inlet
Elbow
Grub
Screw

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7. Fit the shower control body onto the
backplate and secure by tightening,
clockwise, the two recessed grub
screws, using the 2.5 mm A/F hexagon
wrench (supplied).
8. Refit the elbows in the required position,
i.e. rising or falling supplies. Ensure the
grub screws locate into the 'V' groove
and tighten the grub screws.
9. Assemble the components of the inlet
connector compression fittings in the
following sequence for each inlet:-
9.1. Place the fibre gasket against
the shoulder of the 1/2" BSP
inlet connector nipple.
9.2. Screw, clockwise, the 1/2"
BSP connector nipple into
the elbow ensuring that the
compression taper faces
uppermost, using a 12 mm A/F
hexagon wrench (not supplied).
Rising Supplies
Falling Supplies
Connector
Nipple
Fibre
Gasket
Fibre Gasket
15 mm Compression
1/2" Male BSP
Backplate
Shower Control Body
Grub Screws

17
9.3. Slide, in turn, the compression
nut, then the olive, over the hot
and cold inlet pipework. If
necessary, sparingly, smear
‘liquid jointing’ on the pipe end
and the outside of the olive.
9.4. Insert the hot and cold inlet
pipework into the opening of the
1/2" BSP inlet connector nipple
then slide the olive and
compression nut into place.
9.5. Finally, carefully tighten,
clockwise, the compression nut.
If necessary use a cloth to
protect the plated surfaces.
10. Fit the ‘O’ seal to the tapered end of the
outlet nipple and screw it into the shower
control outlet using a 12 mm A/F
hexagon wrench (not supplied). This will
leave the flat face for connection to the
shower hose.
11. This completes the installation of the
Mira CombiForce 415 for “Rising or
Falling Inlet Supplies”.
'O' Seal
Compression
Nut
Olive

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Back Inlet Supplies
1. Follow the shower control installation
procedure as for “Rising or Falling
Inlet Supplies”: instructions 1. to 4.
inclusive.
2. Using a spirit level, mark the route of
incoming hot and cold water supply
pipes at a distance of 153 mm centres.
3. Remove the plaster and brickwork to the
required depth to conceal the supply
pipework.
Note! Depthmust be sufficient to prevent
pipe concealing plates fouling on the
plumbing elbows.
4. Install the hot and cold water supply
pipework ensuring that the pipe ends
emerge from the wall surface at 153mm
centres, and project from the finished
wall surface by 13 mm. Allow for two
circular recesses measuring 32 mm
diameter x 10 mm depth, to accept the
two pipework concealing plates.
5. Make good the wall surface.
Fit the pipework concealing plates over
hot and cold water supply pipework.
Backplate
Concealing
Plate
32 mm
13 mm from
finished wall
surface
10 mm minimum
between elbow
and finished wall
surface.
153 mm
Circular
Recess
Elbow

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Fibre
Gasket
6. Fit the gaskets to the1 /2" BSP connector
nipples and screw in the nipples with the
tapered ends outermost to accept the
compression fittings. Tighten the 1/2"
BSP connector nipples fully with a
12 mm A/F hexagon wrench (not
supplied).
7. Thoroughly flush the incoming hot
and cold water supply pipes before
connectingtheshowercontrol.Failure
to do so may result in product
malfunction.
8. Slip the compression nuts and olives
over the supply pipes.
9. Locate the shower control body onto the
backplate and inlet supply pipework,
then secure by tightening, clockwise,
the two recessed grub screws, using the
2.5 mm A/F hexagon wrench (supplied).
Tighten the compression nuts, using if
necessary, a cloth to protect the plated
surfaces.
Turnonthewatersuppliesandcheck
for any leaks!
10. Fit the ‘O’ seal to the tapered end of the
outlet nipple and screw it into the shower
controloutlet using a 12mm A/F hexagon
wrench (not supplied). This will leave the
flat face for connection to the shower
hose.
11. This completes the installation of the
Mira CombiForce 415 for “Back Inlet
Supplies”.
Connector Nipple
Fibre
Gasket
Connector Nipple
'O' Seal
15 mm
Compression
1/2" Male
BSP
'O' Seal

20
Mira CombiForce 415B Built-in Shower Control
The building-in depth for the integral wall
mounting bracket assembly is 58mm. The
building-in depth for the shower control (to
the finished wall surface) is between 64and
81 mm. The building-in depth calculation
must include the final thickness of plaster
and tiles. This dimension determines how
much of the control knob will be visible
through the concealing plate when the
installation is completed.
Outlet Port
Hot
Inlet
Port
Shower
Control
Building-in
Shroud
Raised
Portion
The built-in shower control incorporates an
integral wall mounting bracket assembly
which can be used to install the shower into
a solid, dry-lined, stud partition or dry
partition wall structure, shower cubicle or
laminated panel. Installers may wish to
consider other options such as fabricating
rear supports using wooden noggins,
however,these methodsof fixing are beyond
the scope of this guide.
A building-in shroud is supplied, which protects the shower control during plastering
and provides a reference for the building-in depth when chasing out the wall surface.
The built-in shower control has 1/2" BSP male inlets and is supplied with 15 mm
compression fittings. The outlet has a 1/2" BSP tapping and supplied with a nipple
terminating in a 1/2" BSP male or 15 mm compression fitting.
230
134
110
146
214
53
43
67
92 A/F
12
38
Wall
Mounting
Bracket
Backplate
Ø101