WorksheetsHot Water - PPT 4 - Instantaneous hot water heaters
Total questions: 21
Worksheet time: 11mins
What are localised systems often called?
Central systems
Single-point or point-of-use systems
Distributed systems
Multi-point systems
Which of the following is a category of localised systems?
Central heating systems
Thermal stores
Instantaneous type heaters
Gas-fired boilers
What do gas- or oil-fired combination boilers have in addition to operating like localised instantaneous hot water heaters?
A cooling capability
A central heating capability
A storage capability
A solar heating capability
What is the primary use of localised instantaneous water heaters?
To heat large quantities of water for industrial use
To supply small quantities of hot water to hand-wash basins and showers
To cool water for refrigeration purposes
To store hot water for long periods
What happens when the control valve (tap) of a localised instantaneous water heater is closed?
The water flow increases
The heat source continues to operate
The water flow stops and the heat source shuts down
The heater stores the hot water
What is the typical minimum water pressure required for localised instantaneous water heaters?
0.5 bar
1 bar
2 bar
3 bar
Where are over sink heaters typically fitted?
Under a sink
Over an appliance
Inside a wall
On the floor
What is the main difference between under sink heaters and over sink heaters?
Under sink heaters require a special tap or mixer tap.
Over sink heaters have a larger capacity.
Under sink heaters are more energy efficient.
Over sink heaters are easier to install.
What is the typical capacity of under sink heaters?
Up to 15 litres
Up to 10 litres
Up to 20 litres
Up to 25 litres
What principle does the multi-point instantaneous water heater use to create a pressure differential?
Newton's law
Bernoulli's principle
Archimedes' principle
Pascal's law
What is the function of the venturi tube in a multi-point instantaneous water heater?
To store hot water
To heat the water
To create a pressure differential
To cool the water
What is a key feature of multi-point instantaneous water heaters regarding water storage?
They have a large storage tank
They have no storage capacity
They store water in a heat exchanger
They store water in a combustion chamber
What is the primary function of combination boilers?
To provide only central heating
To provide only hot water
To provide both instantaneous hot water and central heating
To store hot water for later use
What happens when a hot tap is opened in a combination boiler system?
The boiler stops heating
The water is diverted to a second heat exchanger
The boiler switches to central heating mode
The system shuts down
How is temperature control managed in combination boilers?
Manually by the user
Through a mechanical thermostat
Electronically, adjusting the burner automatically
By adjusting the water flow manually
How do thermal stores differ from domestic hot water cylinders?
They use a separate boiler
They have their own heat source
They do not use heat exchangers
They are smaller in size
What is used as the heat source in thermal stores?
Electric heater
Solar panels
Gas burner
Wood stove
What is a characteristic of a flueless appliance?
It discharges combustion products into the same area.
It discharges combustion products to the outside air.
It takes air for combustion from the outside.
It can be used continuously for long periods.
How long should a flueless appliance be used continuously?
No more than 5 minutes
No more than 10 minutes
No more than 15 minutes
No more than 20 minutes
Where does an open-flued appliance discharge its products of combustion?
Into the same area
To the outside air via a flue system
Into a sealed chamber
Into a water tank
What is the source of air for combustion in a room-sealed appliance?
From the room it is situated in
From the outside
From a connected air tank
From a neighboring room
