Central Heating Systems

What is a heating system in the context of ACS?

• AJust a boiler
• BA complete system including boiler, pipework, radiators, controls, and expansion vessel✓
• COnly radiators
• DJust a burner

Answer: Heating systems include boiler, distribution pipes, radiators, expansion vessels, and controls.

What are the main types of domestic heating systems?

• AOnly boilers
• BConventional (regular boiler with tank), system (sealed), and combi boilers✓
• CJust radiators
• DVaries only by brand

Answer: Main system types are conventional, system, and combination (combi) boilers.

What is a conventional heating system?

• AJust a boiler
• BA boiler supplying hot water to radiators and a separate cylinder for domestic hot water✓
• COnly combi
• DNot used anymore

Answer: Conventional systems use a boiler, feed and expansion tank, radiators, and cylinder.

What is a system boiler?

• AJust heating a house
• BA sealed boiler supplying radiators and hot water cylinder without a feed tank✓
• CCombi type
• DOlder design only

Answer: System boilers are sealed units supplying sealed heating systems and separate cylinders.

What is a combination (combi) boiler?

• ATwo boilers
• BA single sealed boiler providing heating and instant domestic hot water without a separate cylinder✓
• CJust for heating
• DOnly for large homes

Answer: Combi boilers provide heating and instant hot water in one unit.

What is the purpose of an expansion vessel in a heating system?

• ATo store water
• BTo accommodate water expansion as it heats, maintaining safe pressure✓
• CTo supply water
• DJust storage

Answer: Expansion vessels absorb water volume increases from heating, maintaining safe pressure.

What is the typical system pressure range for a sealed heating system?

• A0-5 bar
• B1-2 bar operating, up to 3 bar maximum✓
• C5-10 bar
• DNo limit

Answer: Sealed systems typically operate at 1-2 bar, with safety relief at about 3 bar.

What is the purpose of a pressure relief valve on a heating system?

• ATo supply water
• BTo automatically release pressure if it exceeds a safe level✓
• CTo increase pressure
• DNot important

Answer: Safety relief valves protect the system by venting excess pressure.

What is the purpose of a filling valve (or loop) on a sealed system?

• ATo drain water
• BTo refill the system and maintain operating pressure✓
• CJust a connection point
• DNot needed

Answer: Filling loops/valves allow refilling sealed systems when pressure drops.

What is a pump or circulator in a heating system?

• AJust a valve
• BAn electric pump that circulates hot water through radiators and pipes✓
• CA filter only
• DNot essential

Answer: Circulation pumps force hot water through the heating system.

What is a 3-port valve in heating systems?

• AWater inlet only
• BA motorized valve that directs water to heating or hot water as needed✓
• CJust a shut-off valve
• DNot used domestically

Answer: 3-port valves direct heated water to heating circuits or water heating as required.

What is a thermostatic radiator valve (TRV)?

• AJust decoration
• BA valve that automatically controls radiator temperature by responding to room temperature✓
• CA shut-off valve
• DAll radiators have them

Answer: TRVs automatically adjust radiator flow based on room temperature.