Mira Excel Operation manual

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SHOWER FITTINGS
Installation & User Guide
MIRA EXCEL THERMOSTATIC
These instructions are to be left with the user
BATH AND SHOWER MIXER

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CONTENTS
Introduction ............................................................................................. 3
Description .............................................................................................. 3
Important Safety Information ................................................................. 3
Pack Contents Checklist ......................................................................... 4
Dimensions ............................................................................................. 5
Specifications .......................................................................................... 6
Connections ......................................................................................... 6
Weight ................................................................................................. 6
Temperature Control ............................................................................ 6
Flow Control ......................................................................................... 6
Operating Parameters .......................................................................... 7
Inlet Supply Pressure ........................................................................... 7
Inlet Supply Temperatures ................................................................... 7
Installation Requirements ...................................................................... 8
Typical Suitable Installations ............................................................... 9
Installation ............................................................................................. 13
Operation ............................................................................................... 15
Commissioning ..................................................................................... 16
Commissioning Checks ..................................................................... 16
Maximum Temperature Setting .......................................................... 17
Fault Diagnosis ..................................................................................... 18
Maintenance .......................................................................................... 20
Flow Regulator Removal .................................................................... 22
Filter Cleaning/Replacement .............................................................. 24
Maintaining the Non-Return Valves .................................................... 26
Removing the Thermostatic Cartridge ................................................ 28
Cleaning and Re-assembly of the Thermostatic Cartridge .................. 30
Replacement of the Flow Cartridge .................................................... 32
Spares .................................................................................................... 34
Accessories ........................................................................................... 34
Customer Service .................................................................... Back Page

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This Mira Excel BSM is a fully thermostatic Bath and Shower mixer, with an integral
flow control and divertor. A patented temperature re-setting mechanism automatically
reduces the maximum allowable temperature when diverting from bath to shower
outlet.
For ease of installation and maintenance this product includes a separate inlet manifold
which allows access to the inlet connections, filters, checkvalves and flow regulators.
It includes maintenance free cartridges: a thermostatic temperature control cartridge
and a ceramic divertor cartridge.
To make sure that the installation complies with Water Supply Regulations (backflow
prevention) the correct type of shower fittings must be fitted.
If you experience any difficulty with the installation or operation of your new Bath
Shower Mixer, 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.
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.
INTRODUCTION
DESCRIPTION
IMPORTANT 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. Anyone who may have difficulty understanding or operating the controls of any
shower or bath tap should be attended whilst showering or bathing. Particular
consideration should be given to the young, the elderly, the infirm, or anyone
inexperienced in the correct operation of the controls.
6. When this product 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.

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1 x Quad Key 
1 x 3 mm Hexagonal Wrench 
1 x 5 mm Hexagonal Wrench 
1 x Gasket 
2 x Backnut Adaptors 
2 x Backnuts 
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PACK CONTENTS CHECKLIST


Tick the appropriate boxes to familiarise yourself with the part names and to
confirm that the parts are included.
Documentation
1 x Installation and User Guide 
1 x Customer Support Brochure 
1 x Mira Excel BSM 

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NOTE:- NOT TO SCALE - All dimensions are in millimetres
DIMENSIONS
180
243 195
145 30
G3/4" Inlets
40
50 113
159
G1/2"
Shower

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Connections
Inlets: 3/4" BSP Male at 180 mm centres.
The connections, when viewed from the front, are: Hot –left, Cold –right.
Shower Outlet: 1/2" BSP Male.
Mira Excel BSM is a fully thermostatic bath and shower mixer with an integral flow
control and divertor. It is recommended that Mira Logic Shower fittings with a 1.25 m
hose are used with this mixer to optimise performance.
Weight
Mira Excel Thermostatic BSM = 6.3 Kg.
Temperature Control
Temperature selection range: full cold to full hot or max temperature limit.
Note! For your safety, the BSM is pre-set to a maximum temperature of 46°C for bath
fill. When diverting from bath fill to shower mode the maximum preset temperature
will be reduced by approximately 6°C. If you require bath fill at a hotter temperature
refer to section: 'Commissioning, Maximum Temperature Setting'.
Note! An increase in bath fill maximum preset temperature will increase the shower
mode maximum preset temperature. We recommend that you do not increase the
bath fill temperature above 48°C.
Warning! It is essential to check the maximum temperature during commissioning
as the setting will change with different supply conditions.
Thermostatic Temperature Control: 35°C - 49°C
Note! Shut down to seepage is only achieved if the hot supply is 12°C above the
blend temperature.
Flow Control
The mixer has an integral flow divertor. No other type of user accessible flow controller
should be fitted to the shower outlet. Flow regulators are fitted to the inlets and to the
shower outlet to control the flow at high pressures. For pressures below 1.0 bar it is
recommended that the flow regulators are removed, refer to section: 'Maintenance,
Flow Regulator Removal'.
SPECIFICATIONS

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Operating Parameters
Inlet Supply Pressure
Maintained Inlet Pressures: 0.2 - 5 bar
Max. Static Pressures: 10 Bar
Note! With low pressure systems (below 1 bar) it may be necessary to remove the
flow regulators fitted to the product as supplied, refer to section: 'Maintenance, Flow
Regulator Removal'. Both hot and cold pressures should be nominally balanced
within ± 10%.
Inlet Supply Temperatures
Recommended Hot: 55°C - 65°C
Recommended Cold: 5°C - 20°C
Note! The mixer can operate at temperatures up to 90°C for short periods without
damage. However for safety reasons it is recommended that the maximum hot water
temperature is limited to 65°C.

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INSTALLATION REQUIREMENTS
Read the section 'Important Safety Information' first.
Installation must be carried out in accordance with these instructions, and must be
conducted by designated, qualified and competent personnel.
1. The installation must comply with the “Water Supply Regulations 1999
(Water Fittings)” or any particular regulations and practices, specified by the local
water company or water undertakers.
2. Before commencing, make sure that the installation conditions comply with the
information given in section: 'Specifications'.
3. Layout and sizing of pipework must be such that when other services are used,
pressures at the BSM inlets are maintained approximately equal and do not fall
below the recommended minimum.
4. Do not install the product in a position in which service access is restricted.
5. Do not fit any form of flow control in the shower outlet, only Mira recommended
fittings should be used.
6. Do not use excessive force when making connections.
7. Do not install the product in a position where it could become frozen.
8. Supply pipes must be flushed to clear debris before connecting the BSM.
9. Conveniently situated isolating valves must be fitted for servicing purposes.
10. If the BSM 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).
Important!
Three flow regulators are supplied fitted to the product. These are required to limit the
flow rate to the bath and shower when installed on high pressure systems (> 1 bar).
On low pressure systems these may need to be removed to increase the flow (refer to
section: 'Maintenance, Flow Regulator Removal').

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Typical Suitable Installations
Key to symbols appearing throughout this guide.
Float operated valve
Stop or servicing valve
BSM
Warning or overflow pipe
Drop tight pressure reducing valve
(PRV)
Twin impeller inlet pump
Tempering valve
Mini expansion vessel
Non-return valve
Instantaneous gas-heated supplies (e.g. combination boilers)
The BSM MUST be installed with a multipoint gas water heater or combination boiler
of a fully modulating design (i.e. where the water draw-off rate indirectly controls
the gas flow rate to the burner).
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) as shown in the
diagram below to ensure that excess pressures do not damage the product. This may
already be fitted within the boiler (check with the manufacturer) and is in addition to
the normally larger central heating expansion vessel.
The hot supply temperature MUST be at least 12°C hotter than the required blend
temperature for optimum performance.
HOTCOLD
Note! For combination boilers you must
remove the green flow regulator supplied
installed in the hot inlet and replace it with
the white flow regulator (supplied). Refer to
section: 'Maintenance, Flow regulator
Removal'.

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Gravity fed supplies
The BSM MUST be fed from a cold water storage cistern and hot water cylinder
providing nominally equal pressures.
Note! For gravity fed supplies you must remove the hot and cold inlet flow regulators
and the outlet flow regulator to make sure that the maximum flow rate is achieved.
Refer to section: 'Maintenance, Flow regulator Removal'.
Mains pressurised instantaneous hot water supplies, 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

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Combined outlet PRV
with internal non-return valves
- Expansion vessel required.
Cold takeoff after PRV
- Expansion pressure taken up by
unvented cylinder expansion vessel.
Unvented mains pressure supplies
The BSM can be installed with an unvented, stored hot water cylinder. Only a
"competent person" as defined by Part G of Schedule 1 of 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.
Reduced pressure to
unvented cylinder
Reduced pressure to
cold inlet of BSM
High Inlet Pressure
Reduced pressure to
cold inlet of BSM
Reduced pressure
to unvented cylinder
High Inlet Pressure
Expansion Vessel
HOTCOLD
Safety devices not
shown for clarity

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Pumped supplies (inlet pumps)
The BSM 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

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INSTALLATION
1. The Mira Excel Thermostatic BSM can be installed on most standard baths and
deck surfaces (refer to illustration).
2. Fit the bath sealing gasket to the mixer with the arrow pointing forward. Carefully
position on the bath (refer to illustration).
Note! Make sure that the gasket provides an adequate seal. If the BSM overhangs
the 'roll' of the bath then silicone sealant must be used.
3. Fit the two backnut adaptors and the two 3/4" BSP backnuts and tighten. Take
care to prevent damage to the bath.
4. Thoroughly flush out the incoming hot and cold water supplies before final
connection of the Excel BSM.
5. Connect the hot and cold water supplies to the inlets.
Important! The hot water supply MUST be connected to the hot inlet. This is
stamped Hon the top of the manifold. Reversed connections could be dangerous
to the person using the mixer. The connections, when viewed from the front, are:
Hot –left, Cold –right.
Min
35 mm
Min
35 mm
180 mm
ø 32 mm
Backnut Adaptor
Backnut
HOT COLD
Shower Outlet

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6. For low pressure systems only, make sure that you remove the three flow
regulators fitted to the hot and cold inlets and to the shower outlet. This will make
sure that the highest possible flow rate is achieved. Refer to section: 'Maintenance,
Flow regulator Removal'.
7. For combination boilers only, make sure that the green flow regulator supplied
installed in the hot inlet is replaced with the white flow regulator (supplied). Refer
to section: 'Maintenance, Flow regulator Removal'.
8. Check the installation for any leaks. Fully open the isolating valves fitted to the
supply pipework.
9. Install the shower fittings, refer to the appropriate section in the Shower Fittings
Installation and User Guide.
10. Connect the shower hose to the shower outlet of the Excel BSM.
11. This completes the installation of the Mira Excel BSM.
Note! Following the installation of your Mira Excel BSM commissioning checks
must be carried out, refer to section: 'Commissioning'

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Temperature Control
The Mira Excel BSM is fitted with a separate On / Off flow divertor and temperature
control handle which operate as follows:-
1. On / Off Flow Divertor
From the Off position, anticlockwise movement immediately turns on the flow to
bath mode, full clockwise movement diverts the flow to shower mode. When
diverting from bath mode to shower mode the maximum preset temperature will
be reduced by approximately 6°C. When diverting from shower mode to bath
mode the temperature will remain at the set showering temperature until adjusted
by the temperature control. The flow rate is determined by the supply pressures
at the inlets of the product control, or by the effective output power of the gas
heater appliance. Flow rates for gas water heaters and combination boilers can
vary typically between 8 l/min (winter) and 15 l/min (summer).
Note! An amount of water may be retained in the bath spout after the flow control
has been turned off. This will drain over a short period of time.
2. Temperature Control
In either the shower or bath fill mode adjustment of temperature is achieved by
clockwise rotation for cooler and anticlockwise rotation for warmer up to the
preset maximum.
Preset maximum outlet bath temperature
Flow Divertor
Off Position
Shower Mode Bath Mode
Off
On On
OPERATION

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Commissioning Checks
After completing the installation the following commissioning checks must be carried
out:
Note! Thermostatic mixing valves with wax capsules could lose their responsiveness
if not used. Valves which have been in storage, installed but not commissioned, or
simply not used for some time should be exercised before setting the maximum
temperature or carrying out any tests.
A simple way to provide this exercise is:
(a) Make sure that the hot and cold water are available at the valve inlets, turn on the
flow divertor to bath mode.
(b) Turn the temperature control rapidly from cold to hot and back to cold
several times, pausing at each extreme.
Maximum Temperature
The maximum blend temperature through the bath or shower outlet should be limited
to prevent accidental selection of a temperature which may be too hot. All Mira
thermostatic mixing valves are fully performance tested individually and the maximum
temperature for the Mira Excel BSM is pre-set under ideal installation conditions at
the factory to approximately 46°C for bath fill. When diverting from bath mode to
shower mode the maximum preset temperature will be reduced by approximately
6°C. Site conditions may dictate that the maximum temperature has to be re-set
following installation or servicing.
To check the temperature:
1. Turn the flow divertor lever to bath mode and run for several minutes in order to
stabilise the temperature. Make sure that the hot and cold water supplies are
within Mira recommendations. Refer to section: 'Specifications'.
2. Turn the temperature control handle to the hot position (fully anticlockwise). To
re-set the maximum temperature refer to section: 'Maximum Temperature
Setting'. The actual temperature may vary depending on the supply conditions.
3. Turn the flow divertor lever to shower mode (Check that an adequate spray pattern
is delivered from the shower head) and measure the shower temperature. This is
automatically set when the flow divertor is turned to shower mode.
4. Turn the flow divertor lever to the OFF position.
Note! Draining of residual water held in the outlet fittings, may continue for a period
after the flow is shut off.
COMMISSIONING

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Maximum Temperature Setting
1. Pull off the temperature control knob.
2. Remove the hub screw using the 3 mm hexagonal wrench (supplied) and remove
the temperature control hub.
3. Rotate the flow divertor lever to bath mode.
4. Rotate the cartridge temperature spindle using the temperature control hub until
the desired bath outlet temperature is obtained from the bath spout.
(clockwise = decrease temperature).
5. Once the desired maximum blend temperature has been achieved (46°C is
recommended for bath fill), refit the temperature control hub without disturbing
the spindle, positioning the hub such that the lug on the temperature hub is
against the left hand side of the temperature stop sleeve (refer to illustration).
Check that the blend temperature has not altered, refit and tighten the hub locking
screw.
6. Replace the temperature control knob.
Maximum Temperature Setting
Temperature Spindle
Temperature Stop Sleeve
Temperature
Control Hub Lug
Temperature Control Knob
Temperature Control Hub
Flow Divertor Lever
- +
Temperature
Hub Screw

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Read the section: Important Safety Information first.
Provided that the BSM has been correctly installed and is operated in accordance
with the instructions contained in this guide, difficulties should not arise. If any
maintenance is required then it must be carried out by a competent tradesperson for
whom the fault diagnosis chart and maintenance instructions are provided. Before
replacing any parts make sure that the underlying cause of the malfunction has been
identified.
FAULT DIAGNOSIS
Symptom Cause/Rectification
1. Only hot or cold
water from mixer
outlet.
a. Inlet supplies reversed. Make sure that the hot
supply is connected to the left, and the cold supply
to the right hand inlet when viewed from the front.
b. The thermostatic cartridge (1598.022) is fitted
incorrectly. Make sure that the hot inlet (marked 'H')
is on the left side.
2. Fluctuating or
reduced flow.
a. Check that the inlet filters are not blocked.
b. Make sure that the minimum flow rate is sufficient
for the supply conditions.
c. Make sure that the maintained inlet pressures are
nominally balanced and sufficient.
d. Make sure that the inlet temperature differentials
are sufficient.
e. Check the thermostatic performance.
f. Flow regulators fitted incorrectly.
g. Airlock or partial blockage in pipework.
3. No flow from mixer
outlet.
a. Make sure that the inlet isolating valves are open.
b. Hot or cold supply failure. Make sure that the hot
and cold supplies are available to the mixer.
c. Refer to symptom 2. above.
4. Blend temperature
drift.
a. Make sure that the inlet valves are open.
b. Hot supply temperature fluctuation.
c. Supply pressures fluctuating.
d. Thermal Cartridge defective.
e. Inlet Filters Blocked.
5. Maximum blend
temperature setting
too hot or too cold.
a. Indicates incorrect maximum temperature setting,
refer section: 'Commissioning'.
b. Refer to symptom 4. above.

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8. Temperature too hot
or too cold.
a. (Too low) Insufficient supply pressures.
b. (Too low) Refer to symptom 2.
c. (Too high) Supply pressure too high.
d. Flow regulators fitted incorrectly.
a. Remove the flow divertor cartridge and check the
cartridge inlet seal. Replace if damaged.
b. If leak persists replace the flow divertor cartridge.
a. Refer to symptom 1.
b. Refer to symptom 4.
Symptom Cause/Rectification
6. Flow rate too low or
too high.
7. Dripping from bath
or shower outlet.

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Mira products are precision engineered to provide satisfactory performance provided
that they are installed and operated in accordance with the recommendations contained
in this guide.
The Mira Excel BSM is designed for the minimum of maintenance in normal use. If a
malfunction occurs with either the temperature control cartridge or the flow divertor
cartridge then this will necessitate a complete cartridge replacement.
Note! The cartridge's contain no internally serviceable parts.
When installed in very hard water areas (above 200 p.p.m. temporary hardness) your
installer may advise the installation of a water treatment device to reduce the effects
of limescale formation.
Cleaning
Many household cleaners contain abrasive and chemical substances, and should not
be used for cleaning plated or plastic fittings. These finishes should be cleaned with
a mild washing up detergent or soap solution, and then wiped dry using a soft cloth.
In-service Tests
The principal means for determining the continuing satisfactory performance of the
mixing valve is the in-service test.
Follow the procedure detailed in the flow diagram “In-service Test Procedure”.
Frequency of In-service Tests
Check for correct blend setting every 6 months.
Follow the procedure detailed in the flow diagram “In-service Test Procedure”,
every 12 months.
MAINTENANCE