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WorksheetsLevel 3 central heating phase 2
Total questions: 27
Worksheet time: 14mins
Which of these is NOT an advantage of underfloor heating, as compared to traditional radiator type systems
· A more even temperature gradient within the room
· Energy efficient
· Ease of control over a number of zones/rooms
Less pipework
What is the typical flow temperature of an underfloor heating system laid in a screeded concrete floor
35–450C
40–450C
50–600C
70–800C
What size pipework is underfloor heating pipework
18mm outside diameter and a 14mm internal diameter,
22mm outside diameter and a 12mm internal diameter,
16mm outside diameter and a 10mm internal diameter,
16mm outside diameter and a 12mm internal diameter,
What temperature can Pex-Al-Pex pipe withstand
Pex-Al-Pex pipes can withstand up to 95ºC
Pex-Al-Pex pipes can withstand up to 85ºC
Pex-Al-Pex pipes can withstand up to 75ºC
Pex-Al-Pex pipes can withstand up to 100ºC
What spacings are normally used for underfloor heating
The pipes are usually installed 100–280mm apart across the floor of the room.
The pipes are usually installed 50–225mm apart across the floor of the room.
The pipes are usually installed 150–225mm apart across the floor of the room.
The pipes are usually installed 250–380mm apart across the floor of the room.
1. Define the term ‘neutral point’ in relation to central heating.
The point where the pump is placed
The neutral point is the point where the vent pipe connects to the heating circuit.
The neutral point is the point where the cold feed connects to the heating circuit.
The neutral point is where the cold feed connects to the vent pipe
What is the minimum recommended height of the open vent pipe beyond the water level of the F&E cistern?
A minimum height of 500mm is normally suitable for fully pumped systems
A minimum height of 1450mm is normally suitable for fully pumped systems
A minimum height of 300mm is normally suitable for fully pumped systems
A minimum height of 450mm is normally suitable for fully pumped systems
What component within a sealed heating system produces the ‘neutral point’ within the system
The expansion vessel creates the neutral point within a sealed system.
The pressure reducing valve creates the neutral point within a sealed system.
The filling loop creates the neutral point within a sealed system.
The non return valvel creates the neutral point within a sealed system.
On an open vented system what is the correct orientation of the vent, cold feed and pump arrangements
Open vent Cold feed pump
Vent cold feed pump
Pump vent cold feed
Pump vent cold feed
What is the maximum distance between the open vent and cold feed on an H-frame
100mm
125mm
150mm
175mm
In order to prevent corrosion and scale build-up in a central heating system, what can be added during initial filling
Vinegar
An inhibitor
Anti-freeze
Descaling solution
What can be incorporated in a heating system to remove magnetite
Scale reducer
Magnetic filters
Water softener
Electrolyte
What is the function of the lock shield valve on a radiator
So the radiator can be removed for redecoration
So the heating circuit can be balanced
So all radiators are receiving adequate heat
To make sure the temperature of the return pipe stays constant
Describe the use of this item
The automatic bypass valve is used to prevent damage to the boiler and pump when TRVs close.
The automatic bypass valve is used to prevent excessive heat build up when TRVs close.
The automatic bypass valve is used to prevent reversed circulation when TRVs close.
The automatic bypass valve is used to prevent damage to the boiler and pump when room thermostat closes.
What is the most suitable position for the installation of an expansion vessel within a central heating system
On the flow pipe near to the boiler
On the cold feed pipe to the system
On the return pipe near to the boiler
On the open vent pipe
where should an AAV be installed
AAVs should be fitted at any high points where air is likely to be trapped.
AAVs should be fitted at any low points where air is likely to be trapped.
AAVs should be fitted where radiators are prone to air locks
AAVs should be fitted at any high points where gas is likely to be trapped.
Air in the system can lead to many issues- which of these is incorrect
corrosion
excessive noise
lack of circulation
Decreased maintenance costs.
When the zone valve closes, the boiler switches off and the circulator stops running, but the programmer is still on; this is known as
This is known as boiler lockout
This is known as boiler outerlock
This is known as boiler break down
This is known as boiler interlock
What is the position for a new wireless room thermostat.
Situated 1.0m up a wall, approximately 3m away from a heat source and not on an outside wall.
Situated 1.5m up a wall, approximately 3m away from a heat source and not on an outside wall.
Situated 1.5m up a wall, approximately 3m away from a heat source and not on an inside wall.
Situated 1.5m up a wall, approximately 2m away from a heat source and not on an outside wall.
What is the recommended maximum surface temperature for heat emitters in schools and NHS properties
Recommended by the HSE to be more than 34°C
Recommended by the HSE to be more than 43°C
Recommended by the HSE to be more than 48°C
Recommended by the HSE to be more than 60°C
What is the minimum distance required between the floor and the bottom of a radiator
Recommended to be no less than 100mm
Recommended to be no less than 150mm
Recommended to be no less than 200mm
Recommended to be no less than 250mm
Which British Standard covers the method for the calculation of design heating loads
BS EN 12831:2003
BS EN 12828:2003
BS EN 14336:2004
BS EN 1264-1:1998
What is the measurement of the U-value
J/m3/K
w/m2K
kj/moC
What is the correct formula to determine the heat loss from a space through air changes and ventilation?
m2 x ∆t x 1.33
m2 x ∆t x U-value
m3 x U-value x QTY x 3
m3 x QTY x ∆t 0.33
What is the most suitable external design temperature for a house with normal sheltered exposure in England and Wales
0c
-1c
-2c
-3c
A room has an internal design temperature of 20oC. Using the answer from Question 7, determine the Delta T between the room and radiator.
Delta T50
Delta T20
Delta T60
Delta T40
What is the purpose of a hot flush of the central heating system?
To remove excess limescale deposits from the system
To ensure that the system flow rates can be achieved throughout the installation
To remove traces of the legionella bacteria from the system pipework
To remove excess jointing compounds, fluxes and oils from the system
