WorksheetsMTL2 Central Heating Learner Outcome 2
Total questions: 40
Worksheet time: 20mins
Wet central heating systems primarily rely on:
Electrical resistance
Solar radiation
Circulation of heated water
Air compression
Heat transfer from radiators occurs by:
Radiation only
Conduction only
Convection only
Conduction, convection and radiation
What causes water to circulate in gravity systems?
Pump pressure
Pipe diameter
Density change due to heating
Valve position
A system with one continuous loop feeding radiators is known as:
Two-pipe system
Sealed system
One-pipe system
Microbore system
Which plan uses a three-port mid-position valve?
S Plan
W Plan
Y Plan
C Plan
A system using two two-port motorised valves is called:
Y Plan
S Plan
W Plan
Gravity system
Which system gives independent control of heating and hot water using two valves?
One-pipe system
Y Plan
S Plan
Semi-gravity system
Which system prioritises hot water over heating?
Y Plan
W Plan
S Plan Plus
C Plan
What component fills an open-vented heating system?
Filling loop
Expansion vessel
Feed and expansion cistern
Pressure relief valve
What is the correct order on an open-vented system?
Pump, vent, feed
Feed, pump, vent
Vent, cold feed, pump
Pump, feed, vent
The neutral point is created when:
Pressure is increased
Vent and cold feed are on the pump suction side
Pump speed is reduced
Expansion vessel is oversized
A sealed system is normally filled to what cold pressure?
0.5 bar
1 bar
2 bar
3 bar
Why must filling loops be removed after filling?
To improve circulation
To reduce pressure
To prevent contamination of the mains supply
To protect the boiler
Typical microbore pipe sizes are:
15mm and 22mm
8mm and 10mm
22mm and 28mm
28mm and 35mm
Microbore systems usually use what component to distribute pipework?
Pump
Valve
Manifold
Heat exchanger
Why are microbore manifolds often centrally located?
Reduce boiler size
Improve aesthetics
Equalise pipe run lengths
Increase pressure
Why must solid fuel systems include a heat leak radiator?
To improve efficiency
To heat unused rooms
To dissipate excess heat safely
To increase pressure
Solid fuel systems must always be:
Sealed
Pressurised
Open vented
Fully pumped only
What type of valve must control a heat leak radiator?
TRV
Wheel-head
Lockshield valve
Motorised valve
Most domestic oil boilers use which fuel?
Diesel
Gas oil
Kerosene
Bio-oil
Pressure jet burners require oil to be:
Heated
Gravity fed
Atomised
Condensed
What ignites fuel in a pressure jet burner?
Pilot flame
Hot surface
Spark ignition
Heat exchanger
Vapourising burners are usually found in:
Modern boilers
Condensing boilers
Older oil cookers
System boilers
What controls fuel delivery in a pressure jet burner?
Thermostat
Fan
Solenoid valve
Expansion vessel
Which boiler type provides instantaneous hot water?
Traditional
System
Combination boiler
Heat-only boiler
Condensing boilers recover heat from:
Combustion air
Flow water
Flue gases
Return pipework
What material must be used for condensate pipework?
Copper
Steel
Plastic
Cast iron
System boilers differ from combi boilers because they:
Are non-condensing
Use open vents
Require a hot water cylinder
Cannot be sealed
Combination boilers are described as:
Heating priority
Energy priority
Hot water priority
Zoned priority
Most heat from modern panel radiators is delivered by:
Radiation
Conduction
Convection
Evaporation
Why are fins fitted to panel radiators?
Improve appearance
Increase radiation
Increase convective heat output
Reduce corrosion
Recommended clearance beneath a radiator is approximately:
50mm
100mm
150mm
300mm
TRVs control temperature by regulating:
Airflow
Voltage
Water flow
Pressure
What causes a TRV pin to move?
Water pressure
Electrical current
Expansion of wax or liquid
Pump speed
What device prevents boiler overheating when valves close?
Room thermostat
Expansion vessel
Automatic bypass valve
Filling loop
What provides boiler interlock?
TRVs alone
Lockshield valves
Correct control wiring
Air vents
Which valve allows flow in one direction only?
Zone valve
Anti-gravity valve
TRV
Diverter valve
What type of sludge is magnetic?
Copper oxide
Aluminium scale
Magnetite
Limescale
Magnetic filters should be installed:
On the flow pipe
On the vent pipe
On the return pipe near the boiler
At the highest point
Which action helps prevent corrosion?
Increasing pressure
Oversizing radiators
Adding corrosion inhibitors
Raising boiler temperature
