Mira FORM Installation & User Guide

1

MIRA FORM

These instructions are to be left with the user

SHOWER CONTROL

Installation and User Guide

2

If you experience any difculty 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.

CONTENTS

Introduction .............................................................................................3

Guarantee ............................................................................................ 3

Safety:Warnings ......................................................................................3

Pack Contents .........................................................................................5

Dimensions ..............................................................................................7

Specications ..........................................................................................8

Normal Operating Conditions: ..............................................................8

Pressures and Flow Rates ...................................................................8

Temperatures ..................................................................................... 10

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 ...............................................................................................24

Fault Diagnosis ......................................................................................27

Maintenance ...........................................................................................28

Spare Parts ............................................................................................40

Accessories ...........................................................................................43

Customer Service .................................................................................. 44

3

The Mira Form Thermostatic mixing valve is specied 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.

Guarantee

For domestic installations, Mira Showers guarantee the Mira Form thermostatic

shower valve against any defect in materials or workmanship for a period of

one year from the date of purchase.

For non-domestic installations, Mira Showers guarantee the Mira Form

thermostatic shower valve against any defect in materials or workmanship for a

period of one year from the date of purchase.

For terms and conditions refer to the back cover of this guide.

Recommended Usage

INTRODUCTION

Application

Domestic

ü

Light Commercial

ü

Heavy Commercial

û

Healthcare

û

SAFETY:WARNINGS

This Mira Form Thermostatic Mixer 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.

4

Caution!

1. Read all of these instructions and retain this guide for later use.

2. Make sure that this guide is left with the user. Pass on this guide in the event

of change of ownership of the installation site.

3. Follow all warnings, cautions and instructions contained in this guide, and on

or inside the shower.

4. Installation must be carried out in accordance with these instructions, and must

be conducted by designated, qualied and competent personnel.

5. The installation must comply with the “Water Supply Regulations 1999 (Water

Fittings)” or any particular regulations and practices, specied by the local water

company or water undertakers.

6. This appliance is not intended for use by persons (including children) with

reduced physical, sensory or mental capabilities, or lack of experience and

knowledge, unless they have been given supervision or instruction concerning

the use of the appliance by a person responsible for their safety.

7. Children should be supervised to make sure that they do not play with the

appliance.

8. Sunburn or skin conditions can increase your sensitivity to hot water.

9. If water leaks from the pressure relief valve, maintenance will be required before

the appliance can be safely used.

10. If the shower is dismantled during installation or servicing then upon completion

the product must be inspected to ensure there are no leaks.

11. DO NOT commission this appliance if water leaks from the unit.

12. DO NOT operate this appliance if water leaks from this appliance.

13. The shower head must be de-scaled regularly. Lack of regular shower head

cleaning will lead to poor performance and cause early failure of the appliance.

Refer to the Shower Fittings User Guide for more information.

14. If pipework and/or electical cables enter the shower from the rear through a hole

in the wall . Provision must be made to prevent water ingress back into the wall

structure.

15. Care is required when adjusting ow or temperature, make sure that the

temperature has stabilised.

16. Make sure that you fully understand how to operate this shower and make sure

that it is properly maintained in accordance with the instructions given in this

manual.

17. Having completed the installation, make sure that the user is familiar with the

operation of the appliance.

18. When this appliance has reached the end of its serviceable life, it should be

disposed of in a safe manner, in accordance with current local authority recycling,

or waste disposal policy.

5

PACK CONTENTS

 Tick the appropriate boxes to familiarize yourself with the part names and to

conrm that the parts are included.

Form Mixing Valve

ü

1 x Concealing Plate 

3 x Compression Nuts 

3 x Olives

1 x RAC Elbow 

1 x Valve Assembly 

(with building-in shroud tted)

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)

6

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 tted)

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 

7

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

8

SPECIFICATIONS

Normal Operating Conditions:

- inlet dynamic pressures nominally balanced to within 10% of each other during

ow.

- a differential of approximately 50

o

C between the hot and cold inlet temperatures,

and with differentials of 15-35

o

C 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 specic 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 ow.

Maximum Static Pressure is 10 bar.

Recommended maximum ow velocity in pipelines is 2 metres/second.

* Pressure Loss Ratio is determined by subtracting the resistance of the outlet

pipework and outlet ttings from the dynamic pressures of the hot and cold water at

the inlets of the mixing valve. This is at its extreme when the mixing valve is used

at its lowest ow-rate and when the maximum inequality occurs in the pressure of

the hot and cold water supplies.

9

Note! For combination type boilers it may be necessary to t the ow regulator

(supplied) to restrict the ow through the boiler to ensure it produces a sufciently

hot water temperature.

Flow Regulator Installation

Flow regulators are supplied with this product and should be tted in High

Pressure systems to either;

1. Reduce Excessive Force & Flow Rate

2. Reduce Noise through the mixer due to high or unequal pressures

3. Stabilise incoming supply temperatures

10

The high capacity spray plate should be tted 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

0 5 252010 15 30

Economy

Soothe

Start

Force

Mira Form with the high capacity sprayplate tted 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

0 5 252010 15 30

Soothe

Start

Force

Mira Form with the low capacity sprayplate tted to the handset

(Maintained supply pressures are equal and outlet temperature set to mid-blend)

Economy

11

Temperatures

Optimum performance is obtained when temperature differentials of 20°C or 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 at

desired ow rate.

Flow Control

The Mira Form shower control has integral ow control; no other user-operated ow

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.

Key to Symbols

INSTALLATION REQUIREMENTS

Mixing Valve

Twin Impeller Pump

Tempering Valve

Pressure Reducing Valve

Single Impeller Pump

Overow

Float operated valve

Mini expansion vessel

Isolating Valve

12

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 ow to the boiler, producing a relatively

constant hot water temperature.

Cold Hot

Gravity Fed Shower - The shower MUST be fed from a cold water cistern and hot

water cylinder providing nominally equal pressure.

13

Unvented Mains Pressure Shower - The shower can be installed with a unvented,

stored hot water cylinder. Only “a competent person” as dened by the Building

Regulations may t this type of system.

Safety devices

not shown

for clarity

Hot

Cold

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.

Cold Hot

14

INSTALLATION

General

Installation must be carried out in accordance with these instructions, and must be

conducted by designated, qualied and competent personnel.

1. Before commencing, make sure that the installation conditions comply with the

information given in section: ‘Specications’.

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.

Pumped Shower - The shower can be installed with an inlet pump (twin impeller).

The pump must be installed on the oor next to the hot water cylinder. Ensure hot

cylinder vent pipe is arranged as shown to enable air separation.

30º - 60º

90º

15

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 ushed

through before connection to the mixing valve.

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 congured hot-left, cold-right. If the existing

hot and cold pipework makes this conguration 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 ow 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 180

o

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. Ret 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’.

16

Foam Outer

Seal

Concealing

Plate

RAC Elbow

15 mm

Compression

Nut and Olive

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.

1. Decide on a suitable position for the

shower control and ttings. 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 t to

the valve. Before tightening the

compression tting 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 x 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

17

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 nished wall

surface) can be between 66 mm and

81 mm. This will accommodate a

nal 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.

155mm

260mm

62mm

75mm

Outer Fixing

Holes

18

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

xed into the wall, t the building-in

shroud and ll 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 xing holes. Remove the

bracket and drill the two 6.0 mm

diameter xing holes. Insert the wall

plugs and t the outlet support bracket

with the xing screws supplied.

12. Make sure that the protective cap is

tted 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 nished 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.

19

Flow Regulator - Installation

For high pressure installations an optional

flow regulator is supplied. Fitting the

regulator will limit the ow to 10 l/min,

and reduce the spray force to a more

comfortable level. The regulator may

also be tted 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 ow regulator as illustrated.

Make sure the ‘O’ seals are tted and

the regulator is the correct way up.

3. Ret the outlet nipple to the RAC.

‘O’ Seal

Outlet

Nipple

‘O’ Seal

Flow

Regulator

Direction of

Waterow

RAC

Shower Fittings - Installation

1. Drill the two 7.0 mm xing 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 xing 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 tted). Do not

overtighten.

8. Place the handset into the slidebar

clamp bracket.

600mm

End Support

Cap

End Support

Fixing Screw

Slidebar End

Soapdish

Slidebar

Note! The clamp bracket is tapered. The handset will only t properly from one

direction. If necessary turn the end of the clamp bracket until the handset will t. 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.

Clamp

Bracket

Assembly

20

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 tted from the front the panel must have a

further nishing layer (e.g. plaster and tiles) applied to cover over the wall mounting

plate and xing screws.

Rear Mounted (4 mm to 19 mm thickness)

To t 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 x 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 t to the valve.

Before tightening the compression

tting 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 xing 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

xing holes to mount the valve. The

concealing plate will cover the xing

screws when tted.

RAC Elbow

15 mm

Compression

Nut and Olive

Inner

Fixing

Holes

Elbow Outlet

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Mira FORM Installation & User Guide

Mira FORM Installation & User Guide

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