Mira FORM Operation manual

1
MIRA FORM
These instructions are to be left with the user
SHOWER CONTROL
Installation & User Guide

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CONTENTS
Introduction ............................................................................................. 3
Safety:Warnings ...................................................................................... 3
Pack Contents ......................................................................................... 4
Dimensions ............................................................................................. 6
Specifications .......................................................................................... 7
Normal Operating Conditions ................................................................ 7
Pressures and Flow Rates ................................................................... 7
Temperatures ....................................................................................... 9
Installation Requirements .................................................................... 10
Installation ............................................................................................. 13
General .............................................................................................. 13
Reversed Inlet Supplies ..................................................................... 14
Installation: Solid and Dry-lined Walls ................................................ 15
Shower Fittings - Installation .............................................................. 18
Installation: Panel walls ..................................................................... 19
Commissioning ..................................................................................... 22
Operation ............................................................................................... 25
Fault Diagnosis ..................................................................................... 27
Maintenance .......................................................................................... 29
Spare Parts ............................................................................................ 41
Customer Service .................................................................... Back Page

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This Form Thermostatic Shower Control is precision engineered and should give
continued safe and controlled performance, provided:
1. It is installed, commissioned, operated and maintained in accordance with
manufacturers recommendations.
2. Periodic attention is given, when necessary, to maintain the product in good
functional order.
The function of a thermostatic mixing valve is to deliver water consistently at a safe
temperature. In keeping with every other mechanism, it cannot be considered as
functionally infallible and as such, cannot totally replace a supervisor’s vigilance
where that is necessary. Provided it is installed, commissioned, operated and
maintained within manufacturers recommendations, the risk of failure, if not eliminated,
is reduced to the minimum achievable.
The Mira Form Thermostatic mixing valve is specified to meet the highest standards
of safety, comfort and economy as demanded by todays users. The Mira Form is
designed, manufactured and supported in accordance with accredited BS EN ISO
9001:1994 Quality Systems.
This Manual covers all Mira Form Thermostatic mixing valves manufactured from
March 2001.
The Mira Form Shower Valve is a thermostatic shower control with independent selection
for temperature and spray force and is suitable for connection to concealed pipework.
Mira Form Built-in, with 15 mm compression inlet/outlet connections. Supplied hot-
left, cold-right but can be reversed.
INTRODUCTION
SAFETY:WARNINGS
If you experience any difficulty with the installation or operation of your new shower
control, then please refer to ‘Fault Diagnosis’, before contacting Kohler Mira Limited.
Our telephone and fax numbers can be found on the back cover of this guide.

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PACK CONTENTS
Tick the appropriate boxes to familiarize yourself with the part names and to
confirm that the parts are included.
Form Mixing Valve
9
1 x Concealing Plate 3 x Compression Nuts 
3 x Olives
1 x RAC Elbow 
1 x Valve Assembly 
(with building-in shroud fitted)
1 x Outer Seal 
6 x Wall Plugs 
6 x Countersunk 
Short Bolts
6 x Countersunk 
Fixing Screws
1 x 2.5mm Hexagonal Key 
1 x Outlet Support Plate 
1 x Wall Clamp Nut (with foam seal)
1 x Right Angled Connector 
(RAC)
1 x 3mm Hexagonal Key
1 x Flow Regulator 
(with ‘O’ seal)

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Documentation
1 x Installation, Operation and Maintenance Guide 
1 x Customer Support Brochure 
Form Fittings
2 x Slidebar
Ends 
1 x High Capacity
Sprayplate 
1 x Clamp Bracket 
1 x Outlet Support Plate 
(with low capacity sprayplate fitted)
1 x Soapdish 
1 x Flexible Hose 
1 x Slidebar 
2 x Hose Seals 
2 x Wall Plugs 
2 x End Supports 
2 x End Plugs 
2 x Fixing Screws 

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DIMENSIONS
DIMENSIONS
600 mm
283 mm
max.
75 mm
184.5 mm
251 mm
152 mm
310 mm
6-21 mm when
front mounted onto
a solid, stud wall
4-19 mm when
rear mounted onto
a panel wall
100 mm
80 mm
62 mm

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Normal Operating Conditions:
- inlet dynamic pressures nominally balanced to within 10% of each other during
flow.
- a differential of approximately 50 oC between the hot and cold inlet temperatures,
and with differentials of 15-35 oC between the blend setting and either supply.
- daily usage of 1-6 hours.
- installation and usage environment not subject to extremes of temperature,
unauthorised tampering or wilful abuse.
Other Applications
For information on other specific applications or suitability, refer to Kohler Mira Ltd,
for Local Agent.
Disinfection
In applications where system chemical disinfection is practised, chlorine can be used
(calculated chlorine concentration of 50 mg/l (ppm) maximum in water, per one hour
dwell time, at service interval frequency). Such procedures must be conducted strictly
in accordance with the information supplied with the disinfectant and with all relevant
Guidelines/Approved Codes of Practice.
If in any doubt as to the suitability of chemical solutions, refer to Kohler Mira Ltd, or
Local Agent.
Pressures and Flow Rates
For optimum performance, dynamic supply pressures should be nominally equal.
Recommended Minimum Dynamic Supply Pressure: 0.15 bar (0.2 bar healthcare).
Recommended Minimum Flow Rate: 8 l/min at mid-blend with equal dynamic supply
pressures.
Recommended Maximum Flow Rate: 200 l/min at mid-blend (which equates to
maximum pressure loss of 3.5 bar).
Maximum Pressure Loss Ratio*: should not exceed 10:1, in favour of either supply,
during flow.
Maximum Static Pressure is 10 bar.
Recommended maximum flow velocity in pipelines is 2 metres/second.
*PressureLossRatioisdeterminedbysubtractingtheresistanceoftheoutletpipework
andoutletfittings fromthedynamic pressuresofthe hotandcold wateratthe inletsof
the mixing valve. This is at its extreme when the mixing valve is used at its lowest
flow-rateandwhen themaximuminequality occursinthepressure ofthehot andcold
watersupplies.
SPECIFICATIONS

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The high capacity spray plate should be fitted to the handset when maintained inlet
pressures are above 1 bar .
1.0
2.0
3.0
0
4.0
Flow Rate (litres/minute)
Pressure Loss (bar)
5.0
05 252010 15 30
Economy
Soothe
Start
Force
Mira Form with the high capacity sprayplate fitted to the handset
(Maintained supply pressures are equal and outlet temperature set to mid-blend)
Mira Form Thermostatic Shower with Fittings
Flow Rate / Pressure Loss Graphs
1.0
2.0
3.0
0
4.0
Flow Rate (litres/minute)
Pressure Loss (bar)
5.0
05 252010 15 30
Soothe
Start
Force
Mira Form with the low capacity sprayplate fitted to the handset
(Maintained supply pressures are equal and outlet temperature set to mid-blend)
Economy

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Temperatures
Optimum performance is obtained when temperature differentials of 20°Cor more
exist between blend and either supply. Blend control accuracy will begin to diminish
at temperature differentials below 12°C.
Blend Temperature Range: Between ambient cold and approximately 60°C,
according to hot water supply temperature.
Thermostatic Control Range: Approximately 25-60°C.
Optimum Thermostatic Control Range: 30-50°C.
Recommended Minimum Cold Water Supply Temperature: 1°C.
Recommended Maximum Hot Water Supply Temperature: 85°C.
Note! The shower control can accept temporary temperature excursions above 85°C
without damage, however operation at such elevated supply temperatures is not
recommended. For reasons of general safety, hot water storage temperatures should
ideally be maintained at between 60-65°C where serving ablutionary applications.
Minimum temperature differential between hot and outlet temperature: 10°C.
Flow Control
The Mira Form shower control has integral flow control; no other user-operated flow
control should be used with this shower control.
Connections
The shower control inlet connections are 15 mm compression (nuts and olives are
provided).
Hot (H) and Cold (C) inlets are clearly marked for the shower control and must be
connected as described in the INSTALLATION section.

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Key to Symbols
INSTALLATION REQUIREMENTS
Gravity Fed Shower - The shower MUST be fed from a cold water cistern and hot
water cylinder providing nominally equal pressure.
Mixing Valve
Twin Impeller Pump
Tempering Valve
Pressure Reducing Valve
Single Impeller Pump
Overflow
Float operated valve
Mini expansion vessel
Isolating Valve

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Unvented Mains Pressure Shower - The shower can be installed with a unvented,
stored hot water cylinder. Only “a competent person” as defined by the Building
Regulations may fit this type of system.
Gas Heated Shower - The shower MUST be installed with a gas water heater or
combination boiler of a fully modulating design. A modulating boiler is one that the
draw off rate is indirectly controlling the gas flow to the boiler, producing a relatively
constant hot water temperature.
Cold Hot
Safety devices
not shown
for clarity
Hot
Cold

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Mains Pressurised Instantaneous Hot Water Shower - The shower installed with
systems of this type is supplied hot water via a tempering valve, this provides relatively
constant hot water and the shower will compensate for temperature changes should
they occur.
Pumped Shower - The shower can be installed with an inlet pump (twin impeller).
The pump must be installed on the floor next to the hot water cylinder. Ensure hot
cylinder vent pipe is arranged as shown to enable air separation.
Cold Hot

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INSTALLATION
General
Installation must be carried out in accordance with these instructions, and must be
conducted by designated, qualified and competent personnel.
1. Before commencing, make sure that the installation conditions comply with the
information given in section: ‘Specifications’.
2. Care must be taken during installation to prevent any risk of injury or damage.
3. The mixing valve should be positioned for easy access during use and
maintenance. All routine maintenance procedures can be conducted with the
mixing valve body in place (except for strainer and checkvalve access). For all
models, allow a minimum 80 mm clearance in front of the temperature control to
enable removal of the serviceable parts during maintenance.
4. The use of supply-line or zone strainers will reduce the need to remove debris at
each mixing valve point. The recommended maximum mesh aperture dimension
for such strainers is 0.5 mm.
5. Pipework must be rigidly supported.
6. Pipework dead-legs should be kept to a minimum. The mixed outlet water piping
should not exceed 2 m and the overall length from the hot water circuit to the
discharge point should not exceed 5 m.
7. Supply pipework layout should be arranged to minimise the effect of other outlet
usage upon the maintained pressures at the mixing valve inlets.
8. Inlet and outlet threaded joint connections should be made with PTFE tape or
liquid sealant. Oil-based, non-setting jointing compounds should not be used.
9. To eliminate pipe debris it is essential that supply pipes are thoroughly flushed
through before connection to the mixing valve.

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Reversed Inlet Supplies
It is essential the inlet supplies correspond with the red and blue markings on the
thermostatic cartridge for the Mira Form to operate correctly. The shower control is
supplied with the inlet connections configured hot-left, cold-right.If the existing hot
and cold pipework makes this configuration inconvenient the cartridge inlets can be
reversed.
The connections can be altered by rotating the thermostatic cartridge through 180°,
before or after installation is complete.
1. If the mixing valve body has already been installed, turn off the supplies to the
mixing valve, and open the flow control. This will release the trapped water pressure
and assist in draining residual water.
2. Remove the knob and cover assemblies. Refer to section: ‘Maintenance,
Removing/Fitting Knob and Concealing Plate Assemblies’.
3. With the removal clip still in place, unscrew the head nut using a 35 mm A/F
wrench; this will begin to draw the thermostatic cartridge out of the body.
Note! Some residual water may be released. Pull the thermostatic cartridge free
of the valve body.
4. Rotate the thermostatic cartridge through 180o and carefully push the cartridge
back into the valve body, checking that the 2 cartridge inlet port seals remain in
place, and locate the cartridge lugs into the body slots.
Note! The red and blue markings on the cartridge will now not correspond with
the body markings, to avoid future confusion remove the red and blue stickers
from the valve body.
5. Carefully align and then tighten the head nut, do not overtighten.
6. Complete the Installation, if appropriate.
7. If the mixing valve body has already been installed, restore hot and cold supplies
and check for any leaks.
8. Refit the knob and cover assemblies; refer to section: ‘Maintenance,
Removing/Fitting Knob and Concealing Plate Assemblies’.
9. The maximum temperature may now need resetting, check the outlet water
temperature, and if necessary refer to section ‘Commissioning’.

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1. Decide on a suitable position for the
shower control and fittings. Ideally the
shower should be fitted at a convenient
height for all the family, facing down
the centre-line of the bath or across
the shower cubicle opening.
2. Determine whether the hot or cold water
supplies will connect to the shower
control from the top (falling) or from
the bottom (rising).
3. Remove the control knobs and the
building-in shroud from the valve. Refer
to MAINTENANCE for detailed
instructions on Removing/Fitting
Knob and Concealing Plate
Assemblies. Familiarise yourself with
the hot and cold inlets for the valve.
4. Fit the compression nut and the olive
onto the RAC elbow and fit to the valve.
Before tightening the compression
fitting ensure the pipe is pushed all
the way into the valve outlet and the
elbow outlet is inline with the
control knobs, otherwise the elbow
will fail to line up with the hole in the
concealing plate.
5. Peel off the backing on the adhesive
side of the foam outer seal and fix the
seal in the machined groove on the
back of the concealing plate.
Hot water
inlet falling
or rising
supply
Cold water
inlet falling
or rising
supply
RAC Elbow
15 mm
Compression
Nut and Olive
Foam Outer
Seal
Concealing
Plate
Elbow Outlet
Installation: Solid and Dry-lined Walls
Shower Control - Installation
The Mira Form can be built into solid, dry-lined, stud partition or dry partition wall
structures. All plumbing connections are 15 mm compression.
A building-in shroud is supplied, which can provide a depth reference when chiselling
out the wall surface and protects the shower control during plastering.

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6. Mark the route of the inlet pipework
and the approximate shape of the
recess.
7. Remove the plaster and
brickwork/dry-lining to the required
depth using the building-in shroud as
a reference. The wall mounting bracket
requires a minimum building-in depth
of 60 mm.
The total building-in depth for the
shower control (to the finished wall
surface) can be between 66 mm and
81 mm. This will accommodate a final
thickness of plaster and tiles of
between 6 mm and 21 mm.
8. Mark the position of the wall mounting
bracket outer fixing holes. Drill a
6.0 mm diameter hole at each of the
marked positions and insert the wall
plugs (supplied).
9. Fit the supply pipes into the cut
channels. Flush the hot and cold
water supply pipes thoroughly. The
supplies must be clean and free
from debris before connecting the
shower control. Failure to do so
may result in product malfunction.
60mm 21 mm
max.
6 mm
min.
Outer Fixing
Holes
155mm
260mm 62mm
75mm

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Protective
Cap
Building-in Shroud
Outlet Support
Bracket
Hot and
Cold Inlets
Outlet
10. Fit the valve and connect the supply
pipework. Check the hot and cold
supplies have been connected to the
correct inlets. If necessary the valve
inlets can be reversed, refer to
Reversed Inlet Supplies for further
information.
Note! If the wall screws cannot be
fixed into the wall, fit the building-in
shroud and fill the cavity behind the
mounting bracket with an appropriate
material (e.g. expandible foam).
11. Fit the outlet support bracket over the
RAC elbow and mark the position of
the two fixing holes. Remove the
bracket and drill the two 6.0 mm
diameter fixing holes. Insert the wall
plugs and fit the outlet support bracket
with the fixing screws supplied.
12. Make sure that the protective cap is
fitted to the outlet on the RAC elbow,
and place the building-in shroud over
the valve.
13. Plaster and tile up to the edge of the
building-in shroud. Make sure that the
finished wall surface falls
somewhere between the two lines
marked on the shroud.
14. When the wall surface has been
completed, remove the building-in
shroud and outlet cap. If necessary,
cut the shroud to help removal.
15. Turn on the hot and cold supplies and
check for leaks.
16. Fit the concealing plate and secure with
the control knob and outlet assemblies.
Refer to section: ‘Maintenance,
Removing/Fitting Knob and
Concealing Plate Assemblies.

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Flow Regulator - Installation
For high pressure installations an optional
flow regulator is supplied. Fitting the
regulator will limit the flow to 10 l/min, and
reduce the spray force to a more
comfortable level. The regulator may also
be fitted if water conservation is a concern.
1. Unscrew the outlet nipple from the RAC
with a 12 mm A/F wrench (not
supplied).
2. Fit the flow regulator as illustrated.
Make sure the ‘O’ seals are fitted and
the regulator is the correct way up.
3. Refit the outlet nipple to the RAC.
‘O’ Seal
Outlet
Nipple
‘O’ Seal
Flow
Regulator
Direction of
Waterflow
RAC
Shower Fittings - Installation
1. Drill the two 7.0 mm fixing holes for
the slidebar at 600 mm centres,
avoiding any buried cables or pipes,
and insert the wall plugs.
2. Assemble the clamp bracket
components. Push the plastic slidebar
ends into the slidebar.
3. Push the slidebar through the clamp
bracket assembly and soapdish.
4. Fit the bottom end support loosely to
the wall. Insert the fixing screw into
the countersunk hole of the slide bar
end and through the slidebar support.
5. Place the screw through the top end
support and fully tighten. Fully tighten
the bottom end support.
6. Fit the end support caps over the ends
of the slidebar end supports.
7. Screw the hose onto the handset and
the outlet of the shower control (Make
sure the hose seals are fitted). Do not
overtighten.
8. Place the handset into the slidebar
clamp bracket.
600mm
End Support
Cap
End Support
Fixing Screw
Slidebar End
Clamp
Bracket
Assembly
Soapdish
Slidebar
Note! The clamp bracket is tapered. The handset will only fit properly from one direction.
If necessary turn the end of the clamp bracket until the handset will fit. If the clamp
bracket pivots downwards under the weight of the handset the central securing screw
in the bracket will require tightening to hold the handset in position.

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Installation: Panel walls
The Mira Form can be installed through a laminated panel or shower cubicle from
either the front or the rear of the panel. If fitted from the front the panel must have a
further finishing layer (e.g. plaster and tiles) applied to cover over the wall mounting
plate and fixing screws.
Rear Mounted (4 mm to 19 mm thickness)
To fit the Form shower control to the rear face of the panel, the panel thickness
(including plaster and tiles) must be between 4 mm and 19 mm.
1. Remove the control knobs and
building-in shroud from the valve. Refer
to section: ‘Maintenance,
Removing/Fitting Knob and
Concealing Plate Assemblies. Put
the building-in shroud in the correct
position on the wall and draw around it
with a pencil. Cut out the hole in the
panel.
2. Peel off the backing on the adhesive
side of the foam outer seal and fix the
seal in the machined groove on the
back of the concealing plate.
3. Fit the compression nut and olive onto
the RAC elbow and fit to the valve.
Before tightening the compression
fitting make sure that the pipe is
pushed all the way into the valve
outlet and the elbow outlet is inline
with the control knobs, otherwise
the elbow will fail to line up with the
hole in the concealing plate. Fit the
outlet support bracket to the elbow and
secure with the wall clamp nut.
4. Using the valve as a template, mark
and drill the 6 fixing holes to secure
the mounting bracket and the outlet
support bracket in position. If no further
finishing surface is to be added to the
panel use the six inner fixing holes to
mount the valve. The concealing plate
will cover the fixing screws when fitted.
RAC Elbow
15 mm
Compression
Nut and Olive
Inner
Fixing
Holes
Elbow Outlet

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5. Mount the mixing valve securely onto the rear of the panel, with the fixing screws
supplied.
Note! If access is available it may be preferable to make the initial valve/pipework
connections prior to securing the mixing valve to the panel.
6. Important! Always flush through the hot and cold supplies thoroughly before
connection to the mixing valve.
7. Connect the inlet pipework, checking that the hot and cold supplies have been
piped to the correct inlets. Check that all connections are watertight.
8. To complete installation follow the instructions in section: ‘Installation: solid
and dry lined walls’. Refer to section: ‘Commissioning’ before operating the
shower control.
Laminated Panel
(4 mm - 19 mm thick)
Concealing Plate
Foam Outer Seal
Concealing Plate
Wall Clamp Nut
Outlet Seal
Locknut
and Trim
Control
Knob
Assembly
Use the six inner fixing holes to
mount the valve if no further finishing
surface is to be added to the panel.
Outlet Support
Bracket
Right Angle
Connector