WorksheetsPPT 2 - Central heating system principles
Total questions: 28
Worksheet time: 14mins
What does the term 'gravity circulation' refer to in older systems?
Use of a pump to circulate heat
Principle of convection to circulate heat
Use of electricity to circulate heat
Principle of radiation to circulate heat
Why are modern CH systems more efficient than older systems?
They use larger pipes
They incorporate a circulator or pump
They rely solely on gravity
They use less energy
What is a characteristic of a 'C Plan' system?
It uses only gravity for all circuits
It uses only pumps for all circuits
It combines pumped heating circuits with gravity for hot water primary circuits
It uses solar power for heating
What is a drawback of the one-pipe semi-gravity system?
It requires multiple boilers.
It results in each radiator being progressively cooler.
It is more costly to install.
It uses a complex circuit system.
What is the diameter of the primary flow pipe in a one-pipe semi-gravity system?
15mm
22mm
28mm
35mm
What is one advantage of a one-pipe semi-gravity system?
High efficiency
Cheap to install
Compliant with Building Regulations part L
Controlled room temperature
Why might a one-pipe semi-gravity system not be compliant with Building Regulations part L?
It is too expensive
It uses high efficiency boilers
It has uncontrolled room temperature
It is cheap to install
What is the primary function of the open vent pipe in a one-pipe semi-gravity system?
To increase water pressure
To provide a safety outlet
To reduce water temperature
To block air escape
Why should the open vent pipe not have any valves attached?
It could increase water flow
It could cause overheating
It could have disastrous effects if blocked
It could reduce system efficiency
What does the open vent allow while filling the system with water?
Water to escape
Air to escape
Heat to escape
Pressure to increase
What is the minimum diameter required for an open vent pipe in a one-pipe semi-gravity system?
15mm
22mm
30mm
50mm
Why is an open vent pipe fitted in a one-pipe semi-gravity system?
To increase water pressure
To ensure atmospheric pressure and prevent boiling point from exceeding 100°C
To reduce water flow
To increase system temperature
What is the recommended minimum height for the open vent pipe above the water level of the feed & expansion cistern?
200mm
350mm
450mm
600mm
What is the maximum distance allowed between the open vent and the cold feed in a one-pipe semi-gravity system?
100mm
150mm
200mm
250mm
What is the term used to describe the point where the circulating pump acts on both the feed pipe and the open vent pipe with equal suction?
Balance point
Neutral point
Equilibrium point
Central point
What happens if the open vent and cold feed are positioned further apart than the maximum allowed distance?
The neutral point becomes stronger
The pump acts on the open vent pipe with greater force
The neutral point becomes weak
The system shuts down
What is the common capacity of a Feed and Expansion (F&E) cistern?
10 litres
18 litres
25 litres
30 litres
Where should the 15mm cold feed be located in relation to the F&E cistern?
On top of the F&E cistern
Below the F&E cistern
To the side of the F&E cistern
Inside the F&E cistern
What is the minimum height the F&E cistern should be located above the circulator?
0.5m
1m
1.5m
2m
What is one of the purposes of installing an F&E cistern in a one-pipe semi-gravity system?
To increase water pressure
To provide static head for the heating system
To reduce water temperature
To filter impurities from the water
How does an F&E cistern help maintain the heating system?
By cooling the water
By keeping the system topped up after slight water loss
By reducing system pressure
By increasing water flow speed
What is another function of the F&E cistern besides providing static head?
To accommodate system expansion
To decrease water flow
To purify the water
To increase system noise
What is the role of the room thermostat in the two-pipe semi-gravity system?
It controls the temperature of the hot water
It switches off the pump
It mixes the flow and return waters
It increases the water pressure
Why do the flow and return waters not mix in a two-pipe semi-gravity system?
To prevent water contamination
To allow heat emitters to achieve the same temperature
To reduce water pressure
To increase water flow speed
Which component in a two-pipe semi-gravity system controls the pump?
Boiler
Programmer
Room thermostat
Vent pipe
What is the diameter of the cold feed pipe in a two-pipe semi-gravity system?
15mm
22mm
28mm
30mm
What is one advantage of a two-pipe semi-gravity system?
Uncontrolled heat
Boiler cycling
All heat emitters reach the same temperature
Not compliant to Building Regulations part L
Which of the following is a disadvantage of a two-pipe semi-gravity system?
Cheaper to run
Quicker when heating up
Boiler cycling
All heat emitters reach the same temperature
