ответить на вопросы по тексту. CENTRAL HEATING SYSTEMS

There is a wide range of central heating systems available in the marketplace nowadays, but these can all be classified as one of three main types – a combination boiler system, a conventional gravity fed system and a high pressure system that is powered by the main electricity.
Combination Central Heating Systems
Combination boiler systems are the most popular available today. The ‘combi’ doesn’t require a feed tank, hot water cylinder or expansion tank as the water is heated as and when it is required. This allows the boiler to be housed in much smaller areas and is a lot cheaper to run. They only heat the water that is needed.
A combination boiler does not require loft space for large tanks as it heats water at the moment it is required.
Combi central heating systems are paired to electronic controls.
The combi is fed directly by mains electricity.
Moderately sized thermostatically radiators are installed in available space.
As with other heating systems, the combination boiler does have a few drawbacks, the main one being that the water flow rate can be rather low as the water is heated while it travels through the boiler this means that there is no back tank of hot water available. Because of this combination central heating systems are unsuitable for properties with more than one bathroom as simultaneous use will decrease the flow rate too much.
Conventional gravity fed central heating systems
These central heating systems require a boiler, either a system boiler or regular type, the boilers heat the radiators and supply the hot water. The water circulates around the heating system and is then stored for use in a hot water cylinder. The water that is held in the boiler for heating comes from the expansion or feed tank that is installed in the loft of the house. This system makes sure that the central heating systems tank is always full.
To back the feed tank up this type of central heating systems normally has a larger tank that tops up the water cylinder when the water is being used around the household. The water from this tank is drawn into the system by the force of gravity. The major drawback with this central heating system is that you require a large amount of spare loft space to house two tanks and an airing cupboard to install the hot water cylinder.
High pressure central heating systems
This system will supply mains pressure hot water through taps in your household. The water is supplied from the cold water mains and is heated up by a boiler. Central heating systems of this type store the warm water in a storage tank until it is needed. The pressure of the water as it leaves the tap is the same as the pressure of the mains, which in most instances is much higher than you would normally expect.
These particular systems are ideal if your main water pressure is high to start off with, but not suitable if the pressure is low. This system can be costly to install and maintain as some local authorities require an annual maintenance certificate to be issued.

1. ответьте вопросы.

1. What is a large monthly commitment for the majority of people?
2. What do new gas boilers must adhere to according to Government legislation?
3. What is a qualified central heating technician required for?
4. Why is it so important that your gas boiler heating system must be installed by a qualified Gas Safe engineer?
5. Why has the energy efficiency of gas boilers been greatly enhanced?
6. How much will contemporary gas boilers reduce the amount of lost energy through the systems flue by?
7. Do modern digital heating controls add extra efficiency to your household?
8. Is it difficult to install a modern gas boiler system?