Kohler Electric Shower User manual

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THESEINSTRUCTIONSARETOBELEFTWITHTHEUSER
ELECTRIC SHOWER
Installation & User Guide

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Contents
Introduction.......................................................................................................... 3
Important Safety Information .............................................................................4
Pack Contents Checklist......................................................................................7
Specifications ...................................................................................................... 8
Dimensions ....................................................................................................... 8
Wiring Diagram .................................................................................................. 9
Installation Requirements................................................................................. 11
Installation ......................................................................................................... 16
Commissioning .................................................................................................. 21
Operation ........................................................................................................... 22
Fault Diagnosis .................................................................................................. 25
Customer Fault Diagnosis ............................................................................... 25
Installer Fault Diagnosis .................................................................................. 27
Maintenance ...................................................................................................... 30
Cleaning the Inlet Filter ................................................................................... 30
Relief Valve Assembly and Resetting .............................................................. 32
Flow Regulator Assembly/Switch Assembly Removal & Installation ............... 33
Heater Tank-Removal and Installation ............................................................. 36
Thermal Trip-Removal and Installation ............................................................. 39
Spare Parts ........................................................................................................ 40
Guarantee, Customer Care policy, and How to contact us ............................ 44

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Introduction
Thank you for purchasing a quality Mira Zest Shower. To enjoy the full potential of your
new shower, please take time to read this guide thoroughly, and keep it handy for future
reference.
Mira Zest electric showers have separate controls for power selection and for
temperature/flow adjustment. A unique flow regulator stabilises any temperature
changes caused by water pressure fluctuations, which can result from taps being
turned on or off or toilets being flushed.
Products covered by this guide:
Mira Zest 7.5 – An 7.5 kW 240 V AC (6.9 kW 230 V AC) heater. Available in a white
finish.
Mira Zest 8.5 – An 8.5 kW 240 V AC (7.8 kW 230 V AC) heater. Available in a white
finish.
If you experience any difficulty with the installation or operation of your new
shower control, please refer to the FaultDiagnosissection before contacting
Kohler Mira. Our telephone and fax numbers can be found on the back cover
of this guide.
Recommended Usage
Domestic
Light Commercial
Heavy Commercial
Healthcare
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Important Safety Information
WARNING!
1. Products manufactured by us are safe and risk-free, provided that they are
installed, used and maintained in good working order, in accordance with our
instructions and recommendations.
2. THIS APPLIANCE MUST BE EARTHED.
3. In accordance with ‘The Plugs and Sockets etc. (Safety) Regulations’ in force
at the time of installation, this appliance is intended to be permanently
connected to the fixed electrical wiring of the mains system.
4. DO NOT twist the individual cable cores of the live and neutral conductors, as
this will prevent them from entering the terminal block.
5. Make sure that any pipework that could become frozen is properly insulated.
6. DONOToperate this appliance if it is frozen. Allow the appliance to thaw before
using. The shower unit must not be fitted where it may be exposed to freezing
conditions.
7. DONOTfit any form of outlet flow control as the outlet acts as a vent for the tank
body. Only Mira Showers recommended outlet fittings should be used.
8. If water leaks from the pressure relief valve, maintenance will be required
before the appliance can be safely used.
9. There are no user-serviceable components beneath the cover of the appliance.
Only a competent tradesperson should remove the cover.
10. If any of the following conditions occur, isolate the electricity and water supplies
and refer to To contact us, on the back page of this guide.
•The cover is not correctly fitted and water has entered the appliance case.
•The case is damaged.
•The appliance begins to make an odd noise, smell or smoke.
•The appliance shows signs of a distinct change in performance, indicating
a need for maintenance.
•The appliance is frozen.
11. Isolate the electrical and water supply before removing the cover.
12. Mains connections are exposed when the cover is removed.
13. Refer to the wiring diagram before making any electrical connections.
14. Ensure all electrical connections are tight, to prevent overheating.
15. This product is not suitable for areas with very high humidity (i.e steam rooms).
Please consult your installer.

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CAUTION!
1. Read all of these instructions and retain this guide for later use.
2. 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 appliance.
4. The electrical installation must comply with the “Requirements for Electrical
Installations” (commonly referred to as the IEE Wiring Regulations), or any
particular regulations and practices, specified by the local electricity supply
company in force at the time of installation. The installation should be carried out
by an electrician or contractor who is registered, or is a member of, an
association such as:
•National Inspection Council for Electrical Installation and Contracting
(NICEIC), throughout the UK.
•The Electrical Contractors Association (ECA), England and Wales.
•The Electrical Contractors Association of Scotland (ECAS).
5. This is a high power unit; it is essential to contact your electricity supply
company to ensure that the electricity supply is adequate for the purpose.
6. The plumbing installation must comply with the requirements of UK Water
Regulations/Bye-laws (Scotland), Building Regulations or any particular
regulations and practices, specified by the local water company or water
undertakers. The installation should be carried out by a plumber or contractor
who is registered, or is a member of, an association such as:
•Institute of Plumbing (IOP), throughout the UK.
•National Association of Plumbing, Heating and Mechanical Services
Contractors (NAPH & MSC), England and Wales.
•Scottish and Northern Ireland Plumbing Employers’ Federation (SNIPEF),
Scotland and Northern Ireland.
7. This appliance is not thermostatic and can produce scalding temperatures if not
operated in accordance with the instructions given in this manual.
8. Anyone who may have difficulty understanding or operating the controls of any
shower should be attended whilst showering. Particular consideration should be
given to:
•the young
•the elderly
•the infirm
•the disabled
•anyone who suffers from a medical condition that can result in temporary
incapacity (e.g. epilepsy or blackouts).
•anyone inexperienced in the correct operation of the controls.

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9. 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.

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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.
3 x Wall Plugs
3 x Fixing Screws
1 x Mira Zest Electric Shower
Documentation
1 x Installation & User Guide
1 x Installation Template
1 x Guarantee Brochure

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Specifications
Dimensions
205mm 103mm
53mm
310mm

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WiringDiagram

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Plumbing
1. Minimum maintained inlet pressure for satisfactory operation: 0.7 bar
2. Maximum static inlet pressure: 10 bar
3. Minimum static pressure to keep the flow valve closed: 0.5 bar
Electrical
1. The appliance requires a 40 Amp fuse.
2. The terminal block will not accept cable larger than 10 mm2.
StandardsandApprovals
1. This Mira Zest shower complies with all the relevant directives for CE marking.
FlowRateGraph
1. These curves are for the specified outputs at 240 V.
2. All appliance heating elements have a manufacturing tolerance. Flow rates may
be above or below those shown on the flow rate graph.
3. The left-hand axis shows temperature rise.
Temperature rise = (Showering temperature) - (Supply water temperature)
Example:For the Mira Zest 8.5 kW on full power setting with an incoming water supply
at 10°C and a showering temperature at 42°C, the temperature rise is 32°C. The flow
rate is therefore, 4 l/min.
Flow Rate (l/min)
Temperature Rise (°C)
7.5 kW
8.5 kW

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Installation Requirements
Plumbing
1. The Mira Zest 7.5 kW and 8.5 kW electric showers are designed to operate with
a minimum maintained inlet pressure of 0.7 bar up to a maximum static
inlet pressure of 10 bar.
2. The appliance is normally connected to the cold water mains-fed supply.
However, the water supply can be taken from a cold water storage cistern,
provided there is a minimum maintained inlet head of water of 7 metres (the
vertical distance from the base of the cold water storage cistern to the shower
fitting handset). To reduce pressure losses and fluctuations, the cistern-fed
water supply must be independent from other supply draw-offs, and should
avoid long horizontal pipe runs and use swept bends rather than 90° elbows. For
further advice please refer to the back cover of this guide for Mira Showers
contact telephone and fax numbers.
3. The appliance is suitable for installation within the shower area. It is fitted with
a pressure relief device and must be positioned over a water catchment area
with the controls at a convenient height for the user. The shower fitting should
be positioned so that it discharges down the centre line of the bath, or across
the opening of a shower cubicle, and must be directed away from the appliance.
4. The appliance is fitted with an inlet connector assembly that is designed to
accept plumbing supplies from the top or bottom. The water supply can be fed
with 15 mm pipe or 10 mm microbore pipe, suitably adapted into the inlet
connector assembly. If 10 mm microbore is used, then an allowance for
increased pressure loss must be made to ensure that the minimum maintained
inlet pressure is achieved.
5. Do not fit the appliance to the wall and tile up to the case. The appliance must
be fitted onto a finished flat and even wall surface. Otherwise, difficulty may be
encountered when fitting the cover, and subsequent operation of the unit could
be impaired (small pillars moulded on to the back of the case allow air
circulation).
6. Use only the inlet connector assembly supplied with the appliance. Donotuse
any other types of fitting.
7. Refrain from applying excessive force when making any connections. Always
provide mechanical support when making the plumbing connections.
8. This appliance is not designed to be plumbed directly from the rear. For a rear-
entry supply, add an elbow to the supply pipe and connect it as a rising or falling
supply.

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9. Donotinstalltheapplianceinapositionwhereitmaybecomefrozen.The
shower unit must not be fitted where it may be exposed to freezing conditions.
The shower unit must not be used if you suspect it may be frozen.
10. We recommend that a non-restrictive (free-flowing) isolating valve is fitted in the
cold water supply pipe to allow the complete maintenance of the appliance. Do
notuse a valve with a loose washer plate (jumper) as this can lead to a build up
of static pressure.
11. To avoid damage to the case when soldered fittings are used, pre-solder the
pipework and fittings before connecting them to the inlet stub.
12. Supply pipework MUST be flushed to clear debris before connecting the
appliance.
13. The appliance is fitted with a 1/2" BSP male outlet thread, to accept a Mira Zest
shower hose.
14. When installed in very hard water areas (above 200 ppm temporary hardness)
your installer may advise the installation of a water treatment device, to reduce
the effects of limescale formation. Appliance malfunction due to excessive
limescale formation is not covered by the manufacturer’s guarantee. Your local
water company will be able to advise on the hardness of water in your area.

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15. A hose retaining ring is supplied to
prevent the handset from dropping
below the spillover level of the bath
or shower, which could lead to
contaminationfromback-siphonage.
The supplied hose retaining ring should meet the majority of user requirements
for shower installations with flexible outlet fittings. However, there will be
occasions when the hose retaining ring will not provide a suitable solution. In
these instances an outlet double checkvalve must be fitted. This will increase
the required supply pressure typically by 0.1 bar.
Double checkvalves, fitted in the inlet supply to the appliance, cause a pressure
build-up, which could exceed the maximum static inlet pressure for the
appliance.
16. Avoid layouts where the shower hose will be sharply kinked. This may reduce
the life of the hose.
25 mm minimum
Spillover Level
Hose Retaining Ring

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Electrical
1. In a domestic installation, the rating of the electricity supply company fuse and
the consumer unit must be adequate for the additional demand. This is a high-
power appliance, and it is essential to contact your electricity supply company
to ensure that the supply is adequate for the appliance. Voltage drop due to local
heavy demand will reduce the performance of the shower.
2. The appliance mustbeearthedby connecting the supply-cable earth conductor
to the earth terminal.
Supplementarybonding:Within the bathroom or shower room, all accessible
conductive parts of electrical equipment and extraneous conductive parts that
are likely to introduce earth potential, must be electrically bonded to earth using
a minimum cable size of 4.0 mm2if the cable is not mechanically protected (2.5
mm2if mechanically protected).
3. The minimum cable size (cross-sectional area) required is 6 mm2under normal
installation conditions. See note 4.
Important!The shower circuit should be separated from other circuits by at least
twice the diameter of the cable or conduit, and it should not be run through
thermally insulating material or in locations where the ambient temperature is
likely to exceed 30 °C. If any of these conditions are unavoidable it is necessary
to determine the cable size which will prevent damage to the cable caused by
overheating.
4. To obtain full advantage of the power provided by this unit, use the shortest
possible cable route from the consumer unit to the shower.
5. A 30 mA residual current device (RCD) should be fitted. This may be part of the
consumer unit or a separate unit.

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6. A separate, permanently connected supply must be taken from the consumer
unit to the appliance through a double-pole switch, which has a minimum 3 mm
contact separation. The switch can be a ceiling mounted pull-cord type within
the shower room, or a wall mounted switch in an adjacent room.
7. DO NOT twist the individual cable cores of the live and neutral conductors, as
this will prevent them from entering the terminal block.
8. DO NOT exert strain on the terminal block.
9. DO NOT turn-on the electrical supply until the plumbing has been completed.
Plumbing and Electrical Schematic Diagram

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Installation
WARNING! Isolate the electrical and water supplies before installing the shower.
1.
2. Put the installation template on the wall and mark the positions of the top two
fixing holes. Ensure that there are sufficient lengths of supply pipe and electrical
cable to reach the connection points as shown on the template.
3. Remove the installation template and drill the top two fixing holes. Insert the
supplied wall plugs.
CAUTION! Do not drill into cables or pipes in the wall.
4. Thoroughly flush the supply pipe.
5. On the shower, turn both knobs to the full anti-clockwise position.
Decide on a suitable position for the appliance (minimum distance of 200mm
from the ceiling to allow for cover fit and removal). The position of the
appliance and the shower fittings must provide a minimum gap of 25 mm
between the spill-over level of the shower tray/bath and the handset. This is
to prevent backsiphonage
6. Remove the three screws that hold the cover on the shower and remove the
cover.
7. Remove the service tunnel from the shower.
Screws
Cover
Service Tunnel
Shower
Screw

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8. Determine the direction of the
incoming water supply: falling
(entering the shower from the top),
or rising (entering the shower from
the bottom).
Do not use an incoming supply
entering the shower directly from
the back. Add an elbow to the supply
pipe and connect it as a rising or
falling supply.
9. Rotate the inlet connector to suit the
direction of the incoming water
supply.
Inlet Connector
10. The case has thinned sections that
can be removed to allow entry of the
supply pipe and electrical cables.
Remove the top thinned section of
the case for a falling supply, or
remove the bottom thinned section
of the service tunnel for a rising
supply.
11. Do not remove any case if the
electrical cables enter from the back.
Thinned
Section
Thinned
Section
Service Tunnel

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12. Secure the shower to the wall
loosely through the top two fixing
holes, using the supplied screws.
13. Mark the position of the bottom
fixing hole.
14. Remove the shower from the wall.
Drill the bottom fixing hole and insert
the supplied wall plug.
15. Thoroughly flush the mains-fed
cold water supply pipe. The
supply must be clean and free
fromdebrisBEFOREconnecting
the appliance.
16. Replace the shower on the wall and
securethroughthethree fixing holes,
using the supplied screws. Screws
17. Connect the inlet supply pipe to the
inlet connector using a 1/2” BSP
nipple with compression nuts and
olives (shown) or a push-fit
connector.
Inlet Connector
Compression
Nut
Olive
1/2” BSP Nipple
Olive
Compression
Nut
Inlet Supply Pipe

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18. Bring the electrical cables into the case.
19. Strip back sufficient of the outer cable insulation to enable routing to terminal
block.
20. Fit an earth sleeve to the earth wire.
21. Loosen the screws in the terminal block and insert the bare wires into the clamps.
L (Live) = Brown wire
T(Earth) = Green sleeved wire
N (Neutral) = Blue wire
Note!Do not twist the cores of the wires or strain the cables to make them reach
the terminal block.
22. Connect the conductors firmly into the terminal block. Make sure that the bare
cores of each conductor are securely trapped within each conductor clamp.
L
N
Electrical
Cables
Terminal Block
Outlet
Connector
Cold Water Supply Pipe/
Inlet Connector

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24. Replace the service tunnel.
25. Replace the cover. If the cover does not fit easily, rotate the knobs slightly so
that they fit onto the spindles. Do not force the cover.
26. Tighten the three cover screws.
23. If necessary, fit an earth bonding clamp to the supply pipe and ensure that the
bonding complies with the relevant regulations in force at the time of installation.
Spindle
Screws
Cover
Service Tunnel
Screw