FAQs

FAQs

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Shower Types

Question - What is a mixer shower?

Answer - Mixer showers take water from both hot and cold water supplies. They mix the hot and cold to reach a desired temperature. They generally flow faster than electric showers. You can make the flow more forceful by adding a Mira pump. Mixer showers ideal for homes with a plentiful supply of hot water.

Question - What is an electric shower?

Answer - Electric showers only take water from the mains cold water supply. They heat the water when you turn the shower on, by passing it over a heating element inside the shower – in a similar way to how a kettle works. When you shower, you don’t use up and stored hot water – so electric showers are ideal for families and households where there is a limited supply of hot water. Electric showers are always ready to use, any time of the day or night.

Question - What is an all-in-one power shower?

Answer - All-in-one power showers take water from both the hot and cold water supplies. They mix the hot and cold to reach the desired temperature. They produce a more impressive spray force than mixer or electric showers, because an internal pump boosts the water flow. They are ideal for homes with a plentiful supply of hot water.
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Mixer Showers

Question - Do Mira Showers manufacture a mixer shower that will operate with cold water taken directly from an incoming main (high pressure) and hot water from a gravity-fed stored supply (low pressure)?

Answer - This is not a plumbing arrangement we cater for.  Depending upon the model in question, our mixer showers are compatible with the following plumbing systems only:
  • Gravity-fed hot and cold supplies
  • Fully-modulating combination boiler / gas water heater
  • Mains pressurised unvented system
  • Mains pressurised thermal store
  • Gravity-fed hot and cold supplies via remote pump

Question - What is the difference between a pressure-balanced mixer shower and a thermostatic mixer shower?

Answer - Mixer showers are supplied with hot and cold water and these supplies can vary in temperature and pressure.  A pressure-balanced mixer shower recognises and compensates for fluctuations in the incoming water pressure in order to maintain a showering temperature within +/- 1°C.  However, pressure-balanced mixer showers do not make allowances for fluctuations in the incoming water temperature and under such circumstances the water delivered through the shower will be prone to temperature variation.  Thermostatic mixer showers, recognise and compensate for fluctuations in both the incoming water pressure and the incoming water temperature, so if someone runs a tap or flushes a toilet, the shower will adjust to keep the shower temperature within +/- 1°C – important if there are young children or elderly people in your home.

Question - Is the Mira Gem 88 a pressure-balanced or thermostatic mixer shower?

Answer - The Mira Gem 88 is a manual mixer shower, meaning that it is neither pressure-balanced nor thermostatic.  As such it will not compensate for variations on the incoming water pressure and the incoming water temperature, and will therefore be prone to flow and temperature fluctuations under such circumstances.

Question - With regard to combination boilers / gas water heaters, what is meant by fully-modulating and step-modulating?

Answer - The heat output from a fully-modulating combination boiler / gas water heater can be varied from full off to full on, giving you fine control between the minimum and maximum temperatures it produces.  This is performed by the boiler's gas control valve varying the amount of gas it allows through in direct relation to the water outlet flow.  Therefore a mixer shower fed from a fully-modulating combination boiler / gas water heater will allow total control over the blend temperature the shower delivers from full cold to full hot.
 
The gas valve within a step-modulating combination boiler / gas water heater can only be incrementally adjusted (i.e. off, low, medium or high).  Should a mixer shower be fed via a step-modulating combination boiler / gas water heater you would find that once the required blend temperature through the shower is obtained, the boiler would continue heating the water until the next level is reached (i.e. low to medium, or medium to high).  It would then shut off the gas supply until the heated water had moved through the boiler, causing a cool shot of water to pass through the shower valve before the boiler re-ignites.  With these temperature fluctuations, the shower experience would not be considered comfortable.
 
If you are unsure whether a combination boiler / gas water heater is fully-modulating or step-modulating you should contact the manufacturer for advice.

Question - How do I find out what the pipe centres are for my Mira shower?

Answer -

These measurements can be found in the installation guide supplied with your shower. If you don't have it click here to view a copy of it.

Question - I am thinking about buying a new shower. Which shower is suitable for my water system?

Answer -

We have a step-by-step Shower Selector Tool available online to help you find your perfect shower. Click here to view.

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Digital Showers

Question - What is the difference between the pumped and high pressure models?

Answer -

The pumped versions of our Digital Showers include an integrated pump in the digital valve. These pumped versions are designed to be used on low pressure or gravity fed water systems and literally pumps the water to improve the water flow from the shower. The High Pressure versions do not have a pump incorporated into the digital valve as they are designed for use on mains pressurised systems or combination boilers where the water pressure is strong enough to create a satisfying flow.

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Electric Showers

Question - What is the benefit of installing an electric shower with a high kilowatt rating?

Answer - The higher the kilowatt rating of an electric shower, the greater the flow rate and therefore the more powerful the shower will be.  Electric showers heat cold water to the required temperature by restricting the flow rate of water through their integral heater tank (i.e. the higher the required temperature, the longer the water remains within the heater tank and therefore the lower the flow rate of the shower).  To produce the same temperature of water, an electric shower with a high kilowatt rating will have to restrict the flow of water to a lesser extent than an electric shower with a low kilowatt rating.

Question - Do Mira Showers manufacture an electric shower that can be fed from a cold water storage cistern?

Answer - Of all the electric showers Mira presently manufacture, the Mira Elite ST is the only one that must be fed from a cold water storage cistern as opposed to cold water taken directly from an incoming main.  This is because the Mira Elite ST houses an integral pump, and the W.R.A.S. (Water Regulations Advisory Scheme) dictates that mains water cannot be pumped.

Question - What size supply fuse is required when installing an electric shower?

Answer -

Mira manufacture a wide range of electric showers, most of which are available in more than one kilowatt rating.  Listed below are these various kilowatt ratings alongside the minimum fuse size they require when fed with a 240V electrical supply.

7.5kW 40 Amp supply fuse
8.5kW 40 Amp supply fuse
9.0kW 40 Amp supply fuse
9.5kW 40 Amp supply fuse
9.8kW 45 Amp supply fuse
10.8kW 45 Amp supply fuse

Question - What size electrical cable is required when installing an electric shower?

Answer - We are unable to confirm the required cable size for any of our electric showers.  Part P of Schedule 1 to the Building Regulations which was introduced in February 2005 states that information of this nature can only be given by a qualified electrician certified competent for undertaking installation work. As such a Part P registered electrician will need to visit site and investigate the matter as the electrical installation must comply with British Standard 7671.

Question - Do Mira Showers manufacture an electric shower for use in local authority or health care sectors?

Answer - The only electric shower model suitable for this type of application is the Mira Advance ATL (including the 'Flex' and 'Extra' variants). The Mira Advance ATL carries the BEAB (British Electrotechnical Approvals Board) Caremark, which is given after independent testing by BEAB to verify operating safety and temperature control. The standard has been developed by the Association of Manufacturers of Domestic Appliances (AMDEA) in co-operation with leading manufacturers. The Mira Advance ATL is thermostatically controlled, so ensuring a safe and stable showering temperature irrespective of changes in the incoming water pressure or temperature. A sensor within the shower reads the flow and temperature 62 times per second and adjusts the outgoing water temperature to within +/- 1°C. The Adjustable Temperature Limiter (ATL) allows the shower to be set to one of eight maximum temperatures which range from 37°C to 48°C and protects the user from selecting an unsafe showering temperature.

Question - Why does the water delivered by my electric shower cycle between hot and cold continually?

Answer -

Electric showers heat cold water on demand via an integral heater tank. Should the water inside the heater tank become excessively hot, a safety device known as the thermal switch is activated which isolates electrical current to the heater tank and allows the water to cool. Once the water has cooled to a safe temperature, the heater tank's electrical supply is restored so the shower will again deliver heated water.

Should you live in a hard water area you will experience limescale formation on certain parts of your shower, particularly the shower head. A build-up of limescale in the shower head restricts the flow, meaning water cannot escape quickly enough through the shower and remains in the heater tank for longer than necessary. The water will then overheat and, as explained above, cause the thermal switch to operate. To remedy this problem you should ensure that the shower head is descaled on regular basis, using a suitable descalent solution. By the same token, a kink or blockage in the shower hose will also restrict the flow and result in this symptom. Alternatively, the temperature control dial may have been set at too high a level and is therefore causing the water to overheat.

Question - Can I seal an electric shower to the wall?

Answer - Under no circumstances should an electric shower be sealed to the wall.  There are feet in each corner of the shower's rear-casing which keep it proud of the wall by a few millimeters and allow ventilation around the side and back of the shower module.  Without this ventilation it will be prone to overheating which will subsequently cause failure of – or damage to – the internal components.

Question - Why does my electric shower not work as well in winter?

Answer -

We have a useful video that will help explain why this happens. Please click here to view.

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All-In-One Power Showers

Question - Can a power shower be used in conjunction with a combination boiler?

Answer - Under no circumstances can a power shower be fed from combination boiler.  This is because power showers incorporate a pump, and the W.R.A.S. (Water Regulations Advisory Scheme) dictates that mains water – which is what feeds a combination boiler – cannot be pumped.  Contravention of this water regulation carries a substantial fine.  Power showers can only be installed on a conventional gravity-fed plumbing system comprising of a cold water storage cistern and a hot water cylinder.

Question - Can the hot supply pipework rise from the hot water cylinder and travel through the loft-space before dropping down to a power shower?

Answer - Mira recommend against using ‘up-and-over’ pipework as any air not vented out of the system will accumulate at the high-level pipe run.  This will not only diversely affect the shower’s performance but can ultimately lead to an air-lock causing the power shower’s integral pump to burn out.  Mira therefore recommends that the hot supply pipework drops from the top of the hot water cylinder and travels at a low level before rising up to the power shower.

Question - What storage capacity of hot and cold water is required when installing a power shower?

Answer - Mira recommends a minimum hot water storage capacity of 25 gallons and a minimum cold water storage capacity of 50 gallons.
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Shower Trays

Question - What is a 'tiling upstand'?

Answer - A tiling upstand is a 22mm integral vertical extension to two or three sides of a shower tray that, during installation, provides a watertight finish between the tray and the finished wall surface.

Question - What is a 'tiling upstand strip'?

Answer - This is T shaped joint that hooks over the tiling upstand. It is used to eliminate the need to rebate a tray into a solid wall or when there is a void behind a stud partition wall. The T shape hooks behind the plasterboard and tiling upstand and sealant holds the three pieces together, so making a secure connection.

Question - What is the benefit of a 'riser leg'?

Answer - The riser legs can be fitted to the underside of the tray and allows the installer to raise the tray off the floor. This is useful when installing the tray on a solid floor and where the waste cannot be buried in the floor. Accurate adjustments can then be made by raising or lowering the legs to obtain a perfectly level tray.

Question - The riser legs are obstructed by pipework that runs along one wall under the tray. What can I do?

Answer - Mira offer an offset leg adaptor (part no 2.1570.557.WH) which allows the adjustable legs to be installed offset to the tray where the pipework runs. These adaptors increase the gap between wall and leg from 20mm to 85mm.

Question - What is a 'Biocote ' finish?

Answer - BioCote is an anti bacterial agent based on silver ion technology. It reduces bacterial and mould growth by up to 99.9%. Mira incorporate BioCote into the manufacture of all their white Flight and Flight Low shower trays and unlike other protection it will never wear off or wash away. It is incorporated into the product for life!

Question - I have heard that it is important to level a shower tray that is to be used with an enclosure. How 'level' do I need to get the tray?

Answer - The more level the tray, the easier it will be to fit the enclosure and the better the water tight fit.  As long as the tray is stable, usually an out of level tolerance of 2.5mm is acceptable, and with a good quality spirit level this accuracy is easy to achieve. Please check the out of level tolerance, or maximum adjustment of your shower enclosure to ensure a perfect installation.

Question - Which type of 'waste water trap' should I choose?

Answer -

Mira provide the best type of shower waste to suit the end user and to comply with building regulations. All Mira wastes are top access, this means they are suitable for householders to clean out from above as access to the underside of the tray is not required.

Mira wastes are resealing traps with a 50mm water seal which complies with current building regulations.

An Opella waste is recommended and supplied with the Mira Flight tray. A Vortex Waste (part no 2.1697.050.1.0) or similar must be used with a Mira Flight Low shower tray. This high flow rate waste is essential to ensure the Low profile tray does not overflow when in use with powers showers or other high flow rate showers - maximum flow rate 30 litres a minute.

Question - Can I repair a small chip in a Flight shower tray?

Answer - It is possible to repair small chips in the Acrylic shower trays. Repair kits can be found on the high street or from specialist stockists.
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Shower Enclosures

Question - How do I know which enclosure will fit?

Answer -

We have an easy to use step-by-step "Shower Enclosure Selector Tool" to help you find your perfect shower enclosure. Click here to view.

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Mira Service (Repairs/Service/Installation)

Question - Do you repair other products?

Answer -

Unfortunately we can only repair Mira products; we are unable to fix problems with pull cords, waste pumps, extractor fans etc.

Question - Do you install showers, trays and enclosures?

Answer -

We can only repair products. If you require a product to be installed, you will need to appoint a local trade's person to undertake the work for you.

Question - Can you help with repairing my shower?

Answer -

Click here to find out more information on our Fixed Price Servicing and to book a Service Visit.

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Water Systems

Question - I am thinking about buying a new shower. Which shower is suitable for my water system?

Answer -

We have a step-by-step Shower Selector Tool available online to help you find your perfect shower. Click here to view.

Question - How do I know which water system I have?

Answer -

Click here to view a full explanation of the different types of water systems.


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General Questions

Question - Where can I find out information and fault diagnosis for my shower?

Answer -

The product installation guide supplied with your shower contains information on using and installing the shower, along with a simple fault diagnosis section. You can access the installation guides here. Alternatively you can use our Fault Diagnosis Tool

Question - How can I care for my shower, tray or enclosure?

Answer -

Click here to view our "Caring for Your Shower" guide.

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