FAQ overview

Questions

Showers

What is the difference between a pressure-balanced mixer shower and a thermostatic mixer shower?
Can a power shower be used in conjunction with a combination boiler?
Can I seal an electric shower to the wall?
Can the hot supply pipework rise from the hot water cylinder and travel through the loft-space before dropping down to a power shower?
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)?
Do Mira Showers manufacture an electric shower that can be fed from a cold water storage cistern?
Is the Mira Gem 88 a pressure-balanced or thermostatic mixer shower?
What is a mixer shower?
What is an all-in-one power shower?
What is an electric shower?
What is the benefit of installing an electric shower with a high kilowatt rating?
What size electrical cable is required when installing an electric shower?
What size supply fuse is required when installing an electric shower?
What storage capacity of hot and cold water is required when installing a power shower?
Why does the water delivered by my electric shower cycle between hot and cold continually?

Heated Towel Rails

How can I use a towel radiator?
How do I install a towel radiator to my central heating system?
How do I install an electric towel radiator?
My existing radiator is 600mm wide. Can I replace it with a 600mm wide towel radiator?
What are towel radiators made of?
What is a dual use towel radiator?
What is a pipe centre?
What is a towel radiator?
What is BTU?
What is the distance between the radiator and the wall?
Which electric element should I buy for my radiator?
Which parts do I need for dual use towel radiators?
Which parts do I need for electric only towel radiators?
Which parts do I need to plumb a towel radiator to my central heating system?
Which valves do I need?

Answers

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

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.

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

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.

Can I seal an electric shower to the wall?

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.

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

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.

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)?

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

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

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.

How can I use a towel radiator?

There are three ways to use a towel radiator. They :

1) Run off the Central Heating System,

2) Are used with a heating element without any connection to the central heating, or

3) Are used as duel fuel meaning that they are both connected to the central heating and have an electric element inserted into them, which could be used in summer when the central heating is off.

How do I install a towel radiator to my central heating system?

Towel radiators are fitted by using brackets and valves. The four brackets supplied are used to fix the radiator onto the wall. The two entry points at the bottom of the two vertical bars of the radiator are used to connect the radiator to the pipe work. The third entry point on the top is inserted with a small nut called “Air Vent/Bleed Valve” that is used to let trapped air out of the radiator. Brackets and bleed valves are supplied as standard with all ladder type towel radiators for free of charge.

How do I install an electric towel radiator?

Electric only towel radiators are also wall mounted but are not connected to the central heating system. An electric element is inserted into the radiator through one of the entry points at the bottom. The second entry point on the other side is then sealed off by a blanking plug. The radiator is then filled with tap water using the third entry point on the top of the radiator.

Please remember not to fill the radiator to full but leave a gap as big as two inches on the top for heated water to expand and move freely inside the radiator. Once the radiator is filled with water, use the air-vent/bleed valve to seal the third entry point and get a trained electrician to complete wiring.

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

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.

My existing radiator is 600mm wide. Can I replace it with a 600mm wide towel radiator?

Yes, it is possible to do so. However, please note that most conventional radiators would have their inlet points on the sides whereas ladder type towel radiators have their inlet points at the bottom of the two vertical bars facing the floor.

Therefore, if your existing radiator is 600mm wide, you will find that the distance between the two pipes (pipe-centre) is greater than the width of your radiator, perhaps around 630-660mm, while a 600mm wide towel radiator would have its pipe centres as 550mm.

Please take this information into consideration when deciding on the width of your next towel radiator, as any changes in the pipe centres will require adjustment to the pipes.

What are towel radiators made of?

Towel radiators can be manufactured from steel, stainless steel, aluminium and brass. They can be painted, plated in chrome, or just polished for brushed affect finish (stainless steel radiators only).

What is a dual use towel radiator?

A dual use towel radiator is the one that is powered by an electric element but also is connected to the central heating system. The benefit of having a dual fuel radiator is to be able to use it in summer when the central heating system is turned off.

What is a mixer shower?

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 shower pump. Mixer showers ideal for homes with a plentiful supply of hot water.

What is a pipe centre?

The distance between the centre points of the two pipes that, which are part of the central heating, will connect the radiator to the central heating system via two valves. Pipe centres information is needed when installing the pipes.

What is a towel radiator?

Towel radiators are a certain type of radiators that were originally designed to dry towels in bathrooms and kitchens. However in the past decade they have become a standard item in every bathroom in the Ireland.

Furthermore, with the increase in the production of larger sizes, towel radiators are increasingly installed in dining and sitting rooms too due to their elegant and versatile looks.

What is an all-in-one power shower?

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.

What is an electric shower?

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.

What is BTU?

BTU is the abbreviation for British Thermal Unit. BTU as a heating measure is used to determine heat requirements of bathrooms, kitchens and other parts of houses. Technically, one BTU is equal to the amount of heat required to raise the temperature of one pound of liquid water by 1 degree Fahrenheit at its maximum density, which occurs at a temperature of 39.1 degrees Fahrenheit. One BTU is equal to approximately 251.9 calories or 1055 joules.

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

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.

What is the distance between the radiator and the wall?

The actual projection from the wall to the front of the radiator is minimum 90mm and maximum 120mm.

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

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.

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

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

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

We recommend a minimum hot water storage capacity of 25 gallons and a minimum cold water storage capacity of 50 gallons.

Which electric element should I buy for my radiator?

The choice of electric element depends on the size of the radiator and/or the type of use required from the radiator. The heat output figures in Watts may be referred to choose the right electric element for the right size radiator. If only summer use is required, the electric element with the smallest heat output can be chosen.

Which parts do I need for dual use towel radiators?

You will need the following parts for this option;

- Towel Radiator

- Electric Element

- Two Tee pipes

- One Blanking Plug

- A pair of angled valves (regardless of where the pipes are located)

Which parts do I need for electric only towel radiators?

You will need the following parts for this option:

- Towel Radiator

- Electric Element

- One Blanking Plug

Which parts do I need to plumb a towel radiator to my central heating system?

You will need the following parts for this option:

- Towel Radiator

- A Pair of Valves

Which valves do I need?

The type of valves you need depends on the location of the pipes. If they are coming out of the floor you will need a pair of straight valves. If, however, they are coming out of the wall you will need a pair of angled valves.

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