Mira Crescent Owner's manual

1
THESE INSTRUCTIONS ARE TO BE LEFT WITH THE USER
Maintenance Guide
Operation &B
Installation
SHOWER CONTROL
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2
INDEX
Page
SAFETY WARNINGS 3
ADVICE 3
INTRODUCTION 4
DESCRIPTION 4
PACK CONTENTS 5
DIMENSIONS 6
SPECIFICATION 7
INSTALLATION REQUIREMENTS 10
INSTALLATION 13
COMMISSIONING 20
OPERATION 23
FAULT DIAGNOSIS 24
MAINTENANCE 26
SPARE PARTS 34
CUSTOMER CARE Back Cover
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3
SAFETY : WARNINGS
1. It is installed, commissioned, operated and maintained in accordance with the
recommendations given in this Manual.
2. Periodic attention is given, as necessary, to maintain the product in good functional
order. Recommended guidelines are given in the MAINTENANCE section.
3. Continued use of this product in conditions outside the specification limits given
in this Manual can present potential risk to users.
The function of this thermostatic mixing valve is to deliver water consistently at a safe
temperature. This requires that:
The use of the word ‘failsafe’ to describe the function of a thermostatic mixing valve is
both incorrect and misleading. In keeping with every other mechanism it cannot be
considered as being functionally infallible.
Provided that the thermostatic mixing valve is installed, commissioned, operated
within the specification limits and maintained according to this Manual, the risk of
malfunction, if not eliminated, is considerably reduced.
Malfunction of thermostatic mixing valves is almost always progressive in nature and
will be detected by the use of proper temperature checking and maintenance routines.
Certain types of system can result in the thermostatic mixing valve having excessive
‘dead-legs’ of pipework. Others allow an auxiliary cold water supply to be added to
the mixed water from the mixing valve. Such systems can disguise the onset of
thermostatic mixing valve malfunction.
Ultimately, the user or attendant must exercise due diligence to ensure that the delivery
of warm water is at a stable, safe temperature. This is particularly important in such
healthcare procedures as supervised bathing of patients unable to respond
immediately to unsafe temperatures.
ADVICE
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INTRODUCTION
DESCRIPTION
The Mira Crescent thermostatic shower is a built-in shower control with a fixed spray
head suitable for connection to concealed pipework. The Mira Crescent provides
accurate temperature and flow control for single-point installations.
The shower control incorporates a unique sealed-for-life thermostatic cartridge,
utilising proven durability high-technology materials, for extended service-free reliability.
This cartridge employs an advanced 2nd generation ‘thermoscopic’ temperature
sensor to provide water at safe, accurate temperatures for showering or similar
applications.
Also incorporated is a sealed-for-life flow cartridge, utilising ceramic technology to
provide durable and positive control of flow. The shower control inlets are fitted with
strainers and checkvalves, housed within readily-accessible cartridges for easy
maintenance.
The Mira Crescent Thermostatic mixing valves are specified to meet the highest
standards of safety, comfort and economy as demanded by todays users. The Mira
Crescent is designed, manufactured and supported in accordance with accredited
BS EN ISO 9001:1994 Quality Systems.
This Manual covers all Mira Crescent Thermostatic mixing valves manufactured
from May 2001.
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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.
9
Documentation
1 x Installation, Operation and Maintenance Guide 
1 x Customer Support Brochure 
1 x Concealing Plate 
3 x Compression Nuts
3 x Olives 
1 x 6” Deluge head 
1 x Foam Seal 
1 x Building-in Shroud 
1 x Valve Body 
1 x Outer Seal 
4 x Wall Plugs 

4 x Countersunk
Short Bolts

4 x Countersunk
Fixing Screws
1 x Support Bracket 

1 x Hexagonal Key
1 x Rigid Arm and
Backplate Assembly 
OR
1 x 8” Deluge head 
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6
DIMENSIONS
DIMENSIONS
185 mm
265 mm
89 mm
235 mm
6 mm min.
21mm max.
150 mm
max.
62 mm
4 mm min.
19 mm max.
Rear mounted
onto panel
()
Front mounted
onto wall
()
ø 55 mm
411 mm
152mm (6”)
203mm (8”)
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SPECIFICATION
Normal Operating Conditions are considered as:
- inlet dynamic pressures nominally balanced to within 10% of each other during
flow.
- a differential of approximately 50oC between the hot and cold inlet temperatures,
and with differentials of 15-35oC 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, or
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
Maximum Pressure Loss Ratio: 10:1*
Maximum Static Pressure: 10 bar.
Recommended Minimum Flow Rate: 5 litres/minute at mid-blend.
Recommended Maximum Flow Rate: 35 litres/minute at mid-blend.
Mira Crescent with 6” Deluge Head :-
Minimum Maintained Pressure: 0.2 bar. †
(1.0 bar with an instantaneous gas water heater).
Recommended Maximum Maintained Pressure: 4.0 bar.
(To prevent excessive flow rates with the Deluge Head supplied).
Operating Parameters
For optimum performance, dynamic supply pressures should be nominally
equal.
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Pressure Loss - bar
Flow Rate - litres/minute
0
10
20
30
35
00.5 1.0 1.5 3.02.52.0 3.5
25
15
5
Crescent Thermostatic Shower (6” and 8” models)
Flow Rate / Pressure Loss Graph
(Maintained supply pressures are equal and outlet temperature set to mid-blend)
Mira Crescent with 8” Deluge Head :-
Minimum Maintained Pressure: 0.2 bar.
Recommended Maximum Maintained Pressure: 4.0 bar.
(To prevent excessive flow rates with the Deluge Head supplied).
*Pressure Loss Ratio is determined by subtracting the resistance to flow at the outlet
(generally known as “back pressure”, and measured at the outlet of the mixing tap)
from the maintained pressures of the hot and cold water at each inlet of the mixing
tap. This is at its extreme when the mixing tap is being used at its lowest flow rate and
when the maximum inequality occurs in the pressure of the hot and cold water supplies.
†Equivalent to a 2 metre head measured from the underside of the cold tank to the
shower fitting outlet.
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.
Temperature Control
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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: 12°C
Flow Control
The Mira Crescent shower control has integral flow control; no other user-operated
flow control should be used with this shower control.
Connections
The shower control and shower head connections are all 15mm 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
Isolating Valve
Mixing Valve
Twin Impeller Pump
Tempering Valve
Pressure Reducing Valve
Single Impeller Pump
Overflow
INSTALLATION REQUIREMENTS
Float operated valve
Mini expansion vessel
Gravity Fed Shower - The shower MUST
be fed from a cold water cistern and hot
water cylinder providing nominally equal
pressure.
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
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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.
Unvented Mains Pressure Shower - 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.
Pumped Shower (Inlet Pump) -
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.
90°
30°-60°
Air Separation
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Pumped Shower (Outlet
Pump) - The built-in shower
control can be installed with an
outlet pump (single impeller).
The pump MUST be located on
the floor near to the shower
control. The layout and sizing of
pipework MUST be such that
nominally equal inlet supply
pressures are achieved AND
the effects of other draw-offs
are minimized.
90°
30°-60°
Air Separation
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INSTALLATION
Reversed Inlet Supplies
It is essential the inlet supplies correspond with the red and blue markings on the
thermostatic cartridge for the Mira Crescent 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.
General
Installation must be carried out in accordance with these instructions, and must be
conducted by designated, qualified and competent personnel.
1. Before commencing, ensure that the installation conditions comply with the
information given in SPECIFICATION.
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 servicable 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 water outlet 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 dynamic pressures at the mixing valve inlets.
8. Inlet and outlet threaded joint connections should be made with PTFE tape or
liquid sealant. Do not use oil-based, non-setting jointing compounds.
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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1. If the mixing valve body has already been installed, isolate the supplies to the
mixing valve, and turn on the flow control. This will release the pressure and
assist in draining the residual water.
2. Remove the knob and cover assemblies. Refer to Removing/Fitting Knob
and Concealing Plate Assemblies in the MAINTENANCE section for detailed
instructions.
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 cartridge lugs into body slots.
Note! The red and blue markings on the cartridge will now not correspond with
the body markings, so 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 support bracket, foam seal and concealing plate; and secure in position
with the locknuts. Ensure the foam seal remains in place as the locknuts are
screwed back into position. Refit the shield and lever assemblies.
9. The maximum temperature may now need resetting; check the outlet water
temperature, and if necessary refer to COMMISSIONING.
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1. Decide on a suitable position for the shower
control and outlet. Ideally the shower outlet
should be fitted at a convenient height for all
the family, facing down the centre-line of the
bath or across the opening of the shower
cubicle.
2. Determine whether the hot or cold water
supplies will be connected to the shower control
from the top (falling) or from the bottom (rising).
3. Familiarise yourself with the hot and cold water
inlet and outlet ports.
4. Determine the route for the outlet pipework.
5. Mark the route of the inlet and outlet pipework
and the approximate shape of the recess
(185mm high x 155mm wide).
6. 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 and 81 mm. This will
accommodate a final thickness of plaster and
tiles of between 6 and 21 mm.
The Mira Crescent can be built into solid, dry-lined, stud partition or dry partition wall
structures. All plumbing connections are 15mm compression.
A building-in shroud is supplied, which can provide a depth reference when chasing
out the wall surface and protects the shower control during plastering.
Installation: Solid and Dry-lined Walls
155mm
185mm
60mm
21mm
max.
6mm
min.
Installation
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12. Install the outlet pipework and connect to the
shower control. Taking into account the finished
wall thickness ensure the pipework extends far
enough from the wall (at least 15 mm) to allow
for the shower outlet to be fitted. Check for water
leaks.
13. Fit the building-in shroud over the valve in the
recess. Plaster and tile, or finish as appropriate,
up to edge of the building-in shroud. The final
wall surface must fall between the 2 lines
on the building-in shroud.
7. Remove the control knobs and locknuts (refer
to Removing/Fitting Knob and Concealing
Plate Assemblies) and fit the building-in
shroud over the valve.
8. Mark the position of the wall mounting bracket
fixing holes. Drill a 6.0 mm diameter hole at each
of the marked positions and insert the wall plugs
(supplied).
9. Remove the building-in shroud and install the
hot and cold supply pipes.
10. 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.
11. Mount the shower control in the recess and connect the inlet 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).
14. When the wall surface has been completed, remove the building-in shroud. If
necessary cut the shroud to help removal.
15. Fit the support bracket (with the T shaped hole at the top), the concealing plate
seals and the concealing plate to the valve. To ensure an effective seal the main
seal will need to be fitted with the smooth side facing the wall. Cut the tabs away
from the main seal before fitting the concealing plate (refer to Removing/Fitting
Knob and Concealing Plate Assemblies).
Note! Should the wall surface or tiling be uneven, the seal will need to be aided
or substituted with silicone sealant.
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15. Screw the locknuts onto the valve until they firmly lock the concealing plate
against the wall. This will compress the seal and prevent water ingress into the
recess.
16. Refit the locknut shields and the knob assemblies.
17. Place the outlet wall bracket onto the outlet pipe and mark the positions of the
three fixing holes. Drill a 6.0 mm diameter hole at each of the marked positions
and insert the wall plugs (supplied).
Note! Ensure none of the fixing holes are positioned directly over the
connecting pipework. Failure to do so may result in damage to the
pipework when drilling or fixing with screws.
18. Check the outlet pipe extends 15 mm from the wall, if necessary cut to length
and deburr. Flush the outlet pipework thoroughly to ensure it is clean and
free of debris.
19. Fit the wall bracket to the wall. Fit the compression nut and olive onto the pipe.
Tighten the nut sufficiently to make the compression joint. Take care not to damage
the 'O' seal on the compression nut.
20. Fit the rigid arm to the wall bracket assembly and secure by screwing the bracket
shroud onto the wall bracket. Fit the deluge head to the rigid arm.
21. Refer to COMMISSIONING before operating the shower control.
Bracket Shroud
Rigid Arm
Deluge Head
Compression Nut
Compression Olive
Wall Bracket
Shower Outlet Installation
Ensure
‘O’ Seal
fitted
Outlet Pipe
‘O’ Seal
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Installation: - Panel (4 to 19 mm thickness) Rear Mounted
The Mira Crescent incorporates a mounting bracket, enabling the valve to be in-
stalled through a laminated panel or shower cubicle.
The bracket must be in the correct orientation and mounted to the rear face of panels
with a finished thickness of 4-19 mm .
1. 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. Using the valve and the building-in shroud as a template, mark and drill 4 fixing
holes to secure the mounting bracket in position. If no further finishing surface is
to be added use the four inner fixing holes to mount the valve, as the concealing
plate will conceal the fixing screws when fitted.
3. Follow the instructions outlined in Installation: solid and dry lined walls.
4. If access is available it may be preferable to make the initial valve/pipework
connections prior to securing the mixing valve to the panel.
5. Mount the mixing valve securely onto the rear of panel, with the panel fixing
screws (supplied).
6. Important! Flush through the hot and cold supplies thoroughly before
connection to mixing valve.
7. Connect the inlet and the outlet pipework, checking that the hot and cold supplies
have been piped to the correct inlets. Check for water leaks and that all
connections are watertight.
8. Follow the instructions outlined in Installation: solid and dry lined walls. Refer
to COMMISSIONING before operating the shower control.
Installation - Panel (4 to 19 mm thickness)
Use the four inner fixing
holes to mount the valve if
no further finishing surface
is to be added to the panel
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Installation: - Panels (13 mm max. thickness) Front Mounted
To fit the Crescent shower control to the front face of a panel, a further finishing layer
(e.g. plaster and tiles) must be applied to the panel to cover over the wall mounting
plate and fixing screws. This finishing layer can be between 6 and 21 mm thick. The
laminated panel can be a maximum of 13 mm thick.
1. Cut a hole 185 mm high x 155 mm wide in the panel.
2. Using the valve and support bracket as a template, mark and drill 4 fixing holes
to secure the mounting bracket in position. The fixing hole dimensions must be
suitable for the selected securing method, and appropriate for the particular
panel material.
3. Follow the instructions outlined in Installation: solid and dry lined walls.
Note! The inlets accept rising or falling supplies, on thicker panels this may
require the inlet pipework to be configured with elbows or pipe bends immediately
prior to the inlet connections.
4. Plaster and tile, or finish as appropriate, up to the panel hole perimeter only, and
to a maximum thickness of 21 mm over the front face of the mounting bracket.
Protect the mixing valve and pipe connections during this process.
5. Follow the instructions outlined in Installation: solid and dry lined walls. Refer
to COMMISSIONING before operating the shower control.
Installation - Panel (13 mm maximum thickness)
Use the four outer
fixing holes to mount
the valve (panel
fasteners are not
supplied)
Laminated Panel
(maximum thickness 13 mm)
If the shower is front panel
mounted a further finishing
surface (6 to 21 mm thick)
must be applied to the
panel.
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20
COMMISSIONING
Maximum Temperature
The maximum blend temperature obtainable by the user should be limited, to prevent
accidental selection of a temperature that is too hot.
All Mira Thermostatic mixing valves are fully performance tested and the maximum
temperature is preset to approximately 43oC under ideal installation conditions at the
factory.
Site conditions and personal preference may dictate that the maximum temperature
has to be reset following installation.
This shower control is provided with an adjustable temperature control knob, which
allows the user to select the blend temperature between ambient cold up to a preset
maximum.
Maximum Temperature Setting
Check that an adequate supply of hot water is available at the hot inlet of the shower
control.
During resetting, the hot supply to the shower must be as close to the typical maximum
to offset the possibility of any blend shift due to fluctuating supply temperatures.
However, the minimum temperature of the hot water must be at least 12°C above
the desired blend for correct thermostatic operation.
Temperatures should always be recorded using a thermometer with proven accuracy.
Check that both inlet isolating valves are fully open. Turn the temperature knob to
maximum and operate the flow control. Allow the temperature to stabilize and check
the outlet temperature.
Commissioning must be carried out in accordance with these instructions, and must
be conducted by designated, qualified and competent personnel.
Exercising the Thermostat
Thermostatic mixing valves with wax thermostats are inclined to lose their respon-
siveness if not used. Valves which have been in storage, installed but not commis-
sioned, 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) ensure that the hot and cold water are available at the valve inlets, and the
outlet is open.
(b) move the temperature control rapidly from cold to hot and hot back to cold
several times, pausing at each extreme.
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