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WorksheetsUnit 309 Session 7 Central heating research PT5
Total questions: 1
Worksheet time: 14mins
What is the purpose of balancing a central heating system?
To increase the temperature of the system
To ensure an even heat distribution throughout the system
To decrease the overall heat output
To make the radiators operate independently
What do thermostatic radiator valves (TRVs) control?
The pressure of the water in the radiators
The temperature of the water leaving the boiler
The temperature of the room by controlling the flow of water through the radiator
The speed at which the radiator heats up
Which of the following statements is true about most TRVs?
What is the function of wheel head valves?
To allow manual control of the radiator by being turned on or off
To automatically control the temperature of the radiator
To regulate the flow of water through the radiator during system balancing
To increase the flow rate through the radiator
Who is intended to operate lockshield valves?
Any householder
A plumber only
The manufacturer of the radiator
The person installing the heating system
What is the function of automatic air valves in a central heating system?
To prevent water from escaping the system
To allow air to escape from the system while preventing water from entering
To maintain a minimum flow rate through the boiler
To control the temperature of a hot water cylinder
How do automatic bypass valves help in a fully pumped heating system?
They prevent air from being drawn into the system
They control the temperature of the hot water cylinder
They maintain circulation through the boiler and prevent overheating by gradually opening
They seal themselves when water arrives at the valve
Why are automatic bypass valves considered better than fixed bypass valves?
They prevent the system from drawing in air
They take the flow of hot water away from critical parts of the system, which increases efficiency
They are non-electrical and control the temperature of the hot water cylinder
They reduce the efficiency of the system and increase fuel usage
What is the primary purpose of thermo-mechanical cylinder control valves?
To allow air to escape from the system
To maintain circulation through the boiler
To control the temperature of a hot water cylinder
To prevent water from escaping the system
What is the purpose of a thermo-mechanical cylinder thermostat in a gravity circulation system?
To control the flow of water in the system
To provide a minimum standard of hot water control as per Building Regulations
To prevent unwanted gravity circulation to upstairs radiators
To measure the temperature of the water sent to a remote sensor
Where should the sensor of a thermo-mechanical cylinder thermostat be placed?
At the top of the hot water cylinder
About a third of the way up from the bottom of the cylinder
On the vertical flow to the upstairs heating circuit
Near the central heating circulating pump
What is the function of anti-gravity valves in semi-gravity systems?
To allow air to flow in one direction only
To prevent water from flowing in the closed position
To prevent unwanted gravity circulation to upstairs radiators
To measure the temperature of the water in the system
How are anti-gravity valves similar to the single check valves mentioned in earlier chapters?
They control the temperature of the water
They allow water to flow in only one direction
They are positioned on the vertical flow to the upstairs heating circuit
They switch on the central heating circulating pump
What happens when the central heating circulating pump switches on in a system with anti-gravity valves?
The valve closes to prevent heating circulation
The valve opens to allow heating circulation
The valve measures the temperature of the water
The valve prevents the flow of water to the upstairs radiators
Where should drain valves be fitted in a heating installation?
At the highest points in the system
At the lowest points in the system
At the midpoint of vertical drops
Outside the building
What is the purpose of the expansion vessel in a central heating system?
To compress the water in the system
To replace the feed and expansion cistern
To reduce the water temperature
To increase the water flow
What happens to the neoprene diaphragm in the expansion vessel when the system is heated?
It contracts and moves towards the vessel walls
It expands and moves away from the vessel walls
It remains stationary
It ruptures to release excess pressure
What is the pressure on both sides of the diaphragm in the expansion vessel when the mains-pressure cold water enters the heating system?
0.5 bar
1 bar
1.5 bar
2 bar
How can the pressure in the expansion vessel be restored to its original level?
By heating the system
By cooling the system
By adding more water to the system
By pumping the vessel up with a foot pump
