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Worksheetshot water
Total questions: 89
Worksheet time: 1hrs 29mins
Which of the following is a characteristic of a centralised hot water system?
Supplies hot water to a single appliance
Usually sited near to where the hot water is needed
Supplies every hot water outlet from a hot water vessel, heater, or boiler
Only used for small amounts of hot water
What is a localised hot water system typically used for?
Supplying hot water to every outlet in a property
Supplying hot water to a single appliance
Heating large amounts of water
Central heating systems
Which of the following is NOT a feature of a localised hot water system?
Usually sited near to where the hot water is needed
Supplies hot water to a single appliance
Used for small amounts of hot water
Supplies every hot water outlet from a central position
Which type of hot water system contains a vent pipe that is permanently open to the atmosphere?
Open vented systems
Unvented systems
Instantaneous hot water systems
Storage hot water systems
What is a characteristic of unvented hot water systems?
They contain a vent pipe.
They are fed with water from a cold feed cistern.
They are supplied with water directly from the mains supply.
They store an amount of hot water in a central location.
Which type of hot water system heats the water instantly as it is required when a tap is turned on?
Open vented systems
Unvented systems
Instantaneous hot water systems
Storage hot water systems
What do storage hot water systems do?
They contain a vent pipe.
They heat the water instantly as required.
They store an amount of hot water in a central location for distribution.
They are supplied with water directly from the mains supply.
Which of the following is NOT a type of hot water system mentioned in the document?
Direct systems
In-direct systems
Thermal store
Solar water heaters
What type of hot water storage cylinder is used in direct open vented hot water storage systems?
A combination boiler
A direct-type hot water storage cylinder
A thermal store
A multipoint heater
What type of cylinder does not contain a heat exchanger and is heated directly by either a hot water only boiler or an electric immersion heater?
Indirect hot water storage cylinder
Direct hot water storage cylinder
Central heating system cylinder
Combination boiler cylinder
What type of threads are usually used for the primary flow and primary return connections in a direct hot water storage cylinder?
Male-type threads
Female-type threads
Universal threads
Combination threads
Which type of boiler is NOT suitable for use on central heating systems?
Indirect boiler
Combination boiler
Direct hot water only boiler
Condensing boiler
What is the purpose of the 22mm vent pipe in the direct hot water storage system with a small hot water only boiler?
To discharge into the CWSC and seal with a grommet
To connect the heat source to the cylinder
To draw off to the bath and reduce to 15mm to all other appliances
To provide cold feed to the secondary hot water system
Why should back boilers not be fitted on new installations according to Building Regulations Document L?
They are too expensive
They cannot be adequately temperature controlled and are susceptible to boiling
They are too large
They are not energy efficient
What must be avoided in the material of the boiler to prevent contamination of the domestic hot water supply?
Materials that are likely to rust or contaminate the water
Materials that are too expensive
Materials that are too heavy
Materials that are not energy efficient
Which of the following materials is suitable for hot water storage vessels?
Copper
Plastic
Iron
Aluminum
What principle does the hot water circulation from the heat source use?
Conduction
Convection
Radiation
Diffusion
What is the size of the primary flow and return pipework to ensure good circulation?
15mm
22mm
28mm
35mm
What is the temperature difference between the top and bottom of the hot water cylinder due to stratification?
5°C
10°C
15°C
20°C
What is the power rating of the immersion heater used in direct system hot water storage systems?
1KW
2KW
3KW
4KW
What is the recommended temperature setting range for immersion heaters?
45-50°C
50-55°C
55-60°C
60-65°C
Which of the following is a type of Open Vented Indirect Hot Water Storage system?
Direct Hot Water Storage System
Open Vented Double Feed Indirect Hot Water System
Closed Vented Indirect Hot Water System
Single Feed Direct Hot Water System
What is the primary function of the heat exchanger in an Indirect Hot Water Storage Cylinder?
To store hot water
To transfer heat into the water
To cool down the water
To filter the water
What is the main difference between Direct and Indirect Hot Water Storage Cylinders?
The material they are made of
The internal heat exchanger
The size of the cylinder
The type of water they store
What type of system is suitable for use with central heating systems?
Direct Hot Water Storage System
Open Vented Double Feed Indirect Hot Water System
Closed Vented Indirect Hot Water System
Single Feed Direct Hot Water System
What material is the coil in the Double Feed Indirect Hot Water Storage Cylinder typically made from?
Aluminium
Copper
Plastic
Iron
How many cisterns does the double feed indirect system have?
One
Two
Three
Four
What is the purpose of the coil in the secondary hot water system?
To store water
To heat the water through conduction
To circulate the water
To filter the water
How is the water in the modern sealed central heating system circulated?
By gravity circulation
By a circulating pump
By manual operation
By natural convection
What component is used to accommodate the expansion of water in modern sealed central heating systems?
Feed and expansion cistern
Expansion vessel
Storage tank
Overflow pipe
What happens to the water in the central heating system once it is full?
It is changed regularly
It remains unchanged except for some loss through evaporation
It is drained and refilled monthly
It is filtered continuously
What is the purpose of the spherical ball type service valve in the hot water system?
To control the flow of water
To measure the temperature of water
To vent air from the system
To heat the water
How is the height of the 22mm vent from the secondary hot water system determined?
Height of the vent = 150mm + 40mm per metre of system height (m)
Height of the vent = 100mm + 30mm per metre of system height (m)
Height of the vent = 200mm + 50mm per metre of system height (m)
Height of the vent = 120mm + 20mm per metre of system height (m)
What is the diameter of the primary flow and return pipes from the boiler to the coil in the cylinder?
15mm
22mm
28mm
35mm
What type of feed is used for the primary system in the hot water system?
22mm Cold Feed
15mm Cold Feed
28mm Cold Feed
10mm Cold Feed
What is the function of the Single Feed system in the hot water system?
To heat the water directly
To use air entrapment to separate the secondary water from the primary water
To measure the water pressure
To control the water flow
What is the purpose of the special heat exchanger in the indirect, single feed hot water system?
To mix primary and secondary water
To separate primary and secondary water using air bubbles
To heat the water directly from the cold supply
To store hot water for later use
Why is there no need to install a second (feed and expansion) cistern in the indirect, single feed hot water system?
Because the system uses a special heat exchanger
Because the cylinder only requires a single cold feed
Because the system is filled with air bubbles
Because the system uses pumped circulation
What happens when the air bubbles in the heat exchanger rupture?
The primary and secondary water mix
The system stops working
The water becomes too hot
The system requires a new heat exchanger
According to Building Regulation Document L, why is the indirect, single feed hot water system no longer allowed to be installed?
It is too expensive to maintain
It is not energy efficient
It requires routine maintenance and replacement
It uses pumped circulation
What is a characteristic of instantaneous water heaters?
They store hot water for later use
They heat the water directly from the cold supply
They use air bubbles to separate water
They require a secondary hot water system
What is the primary function of thermal stores in a heating system?
To store cold water for later use
To heat water directly from the cold water main through heat exchangers
To cool down hot water for air conditioning
To store gas for heating purposes
At what temperature is the water inside the thermal store typically maintained?
50°C
60°C
80°C
100°C
What is the purpose of the adjustable thermostatic blending valve in a thermal store system?
To increase the water pressure
To blend hot water with cold water to maintain a safe temperature
To store excess hot water
To filter impurities from the water
How do gas-fired instantaneous multipoint water heaters operate?
By storing hot water in a tank
By using the principle of pressure difference to heat water on demand
By using solar energy to heat water
By using electric coils to heat water
What happens when the tap is closed in a gas-fired instantaneous multipoint water heater system?
The water continues to flow
The gas valve remains open
The pressure differential valve equalises and the flow of gas is shut off
The water is stored in a tank
What is the main limitation of instantaneous gas water heaters for small domestic dwellings?
They cannot provide hot water at all.
They can only supply one open hot tap at a time.
They are too expensive to install.
They require a lot of maintenance.
What type of water heaters are also available besides gas instantaneous water heaters?
Solar water heaters
Electric-type multipoint water heaters
Oil-fired water heaters
Coal-fired water heaters
What is the main advantage of combination (combi) boilers?
They are cheaper than other types of boilers.
They combine hot water supply and central heating in a single appliance.
They are easier to install than other types of boilers.
They require less maintenance.
What is the principle used by 'combi' boilers to heat water?
Using solar panels
Using a water-to-water heat exchanger
Using electric heating elements
Using geothermal energy
What is the range of output for different types of combination boilers?
10kW to 20kW
24kW to 50kW
30kW to 60kW
40kW to 70kW
What is a single point (point of use) heater?
A heater that provides hot water to multiple appliances.
A heater that provides hot water to a single appliance.
A heater that stores a large amount of hot water.
A heater that is always outlet controlled.
Which of the following is NOT a type of single point water heater?
Instantaneous single point water heater
Storage single point water heater
Multipoint instantaneous water heater
Hand wash type water heater
What is the typical output of a hand wash type instantaneous single point water heater?
1kW
3kW
5kW
12kW
What feature do many electric showers have to guard against scalding if the pressure or flow rate suddenly drops?
High flow rate technology
Low pressure cut-out
Temperature stabilisation
Electrically operated solenoid valve
What is the capacity of storage point of use heaters?
Less than 5 litres
Less than 10 litres
Less than 15 litres
Less than 20 litres
What is a unique feature of over sink point of use storage water heaters?
They have a swivel spout to direct water.
They are usually outlet controlled.
They tend to drip water from the spout when heating.
They are fitted below the appliance.
Why must over sink point of use storage water heaters be inlet controlled?
To prevent water from being over-pressurised.
To allow the outlet to vent out the expanded water.
To store more than 15 litres of water.
To be sited in cupboards below kitchen sinks.
Where can under sink point of use storage water heaters be sited?
Above kitchen sinks in offices.
In cupboards below kitchen sinks in offices and factories.
Directly to the mains cold supply pipework.
In large dwellings only.
What is the maximum amount of water that unvented under sink point of use storage water heaters can store?
10 litres
20 litres
15 litres
25 litres
What must be fitted if the pipework size is not sufficient to accommodate the expansion of water in unvented under sink point of use storage water heaters?
A larger heater
A pressure reducing valve
A small expansion vessel
A swivel spout
Which of the following is a safety control required for storage heaters?
A. A pressure reducing valve to limit the water pressure to the water heater.
B. A temperature gauge to monitor the water temperature.
C. A water softener to reduce mineral buildup.
D. A filter to remove impurities from the water.
What is the purpose of a single check valve in a storage heater system?
A. To prevent hot water from expanding back through the cold water supply.
B. To reduce the water pressure to the heater.
C. To allow water to expand within the system.
D. To discharge very hot water away from the heater.
Which factor must be considered when choosing a hot water system for a building?
A. The color of the water heater.
B. The quantity and usage of hot water required.
C. The brand of the water heater.
D. The type of flooring in the building.
What is the maximum distance that hot water pipework can be run without the need for a secondary return pipe work system according to the Water Supply (water fittings) Regulations?
A. The distance is not specified.
B. The distance depends on the type of building.
C. The distance is specified by the manufacturer.
D. The distance is specified by the Water Supply (water fittings) Regulations.
What is a "dead leg" in a hot water system?
A. A section of pipe that is always cold.
B. A section of pipe that is always hot.
C. A section of pipe that is unused.
D. A section of pipe that is leaking.
When is a secondary circulation system required in a hot water system?
A. When the hot water takes longer than 30 seconds to reach the tap.
B. When the hot water is too hot.
C. When the hot water is too cold.
D. When the hot water system is new.
What is the maximum recommended length for an un-insulated hot water pipe with an outside diameter of 22 mm?
20 m
12 m
8 m
3 m
Where is the secondary circulation connection usually positioned in relation to the top of the cylinder?
1/4 of the way down
1/3 of the way down
1/2 of the way down
2/3 of the way down
What type of pump must be used in a secondary circulation system to prevent rusty water being drawn from the hot taps?
Steel bodied pump
Plastic bodied pump
Bronze bodied pump
Aluminum bodied pump
Which type of fuel is often supplemented by an electric immersion heater for use in the summer months?
Gas
Oil
Both gas and oil
Coal
Why might combination boilers or instantaneous multipoint heaters be excluded from systems with many hot water outlets?
They are too expensive
They cannot supply the required flow rate
They are difficult to install
They are not energy efficient
Which of the following is NOT a question to consider regarding installation and maintenance costs?
What is the initial cost of the appliances and materials?
How much will it cost to install them?
What is the warranty period of the system?
What are the long term running and maintenance costs?
What is one of the benefits of using a solar hot water supply system?
It offers a 60% saving on running costs over a 12-month period.
It is cheaper to install than other systems.
It does not require any maintenance.
It uses only gas as a fuel source.
What must be considered when balancing the cost of a solar hot water supply system?
The initial high cost of the solar collector and special storage cylinder.
The availability of solar panels.
The color of the solar panels.
The type of water used in the system.
Which type of boilers have helped in the development of more fuel-efficient systems?
Gas and oil boilers.
Electric boilers.
Wood-fired boilers.
Coal boilers.
What is the purpose of feed and expansion cisterns in hot water heating systems?
To supply cold feed water to a heating system and accommodate any expansion of the water.
To heat the water directly.
To store hot water for later use.
To filter impurities from the water.
What is the function of cold water feed cisterns?
To feed cold water to an open vent hot water storage system.
To heat the water.
To store hot water.
To filter the water.
Which type of hot water storage cylinder is heated directly by either a small hot water only boiler or an electric immersion heater?
Single feed cylinder
Double feed cylinder
Directly heated storage cylinder
Combination cylinder
What is a characteristic of a single feed cylinder?
It uses a coil-type heat exchanger.
It incorporates a storage cylinder with a special heat exchanger that uses air entrapment.
It combines the hot water storage cylinder with the cold water feed cistern.
It is suitable for use with central heating systems.
Which type of cylinder contains a coil-type heat exchanger?
Directly heated storage cylinder
Single feed cylinder
Double feed cylinder
Combination cylinder
What is the primary material used for the coil in a double feed cylinder?
Stainless steel
Copper tube
Aluminum
Plastic
What is a combination cylinder used for?
To heat water directly by a small hot water only boiler
To separate the secondary water from the primary water
To combine the hot water storage cylinder with the cold water feed cistern
To use a coil-type heat exchanger
What is the primary function of mains fed multipoint heaters?
To store hot water for later use.
To heat water instantly as it is drawn from the cold water main.
To provide central heating.
To cool water for air conditioning systems.
What is the main advantage of combination boilers?
They can only be used for central heating.
They require a large storage tank.
They combine hot water supply and central heating in a single appliance.
They are only suitable for small properties.
What is a characteristic of hand wash type mains fed point of use water heaters?
They have an output of up to 12Kw.
They are usually around 3Kw output and fitted over a single washbasin.
They are used for central heating.
They require a large storage tank.
What feature do many electric showers have to prevent scalding?
A large storage tank.
A low pressure cut-out.
A manual temperature control.
A built-in water filter.
What is the maximum temperature of stored hot water according to the document?
48°C
51°C
60°C
70°C
What is the temperature limit for hot water supplied to baths in domestic properties?
48°C
51°C
60°C
70°C
