Central Heating Flashcards
Low pressure open vented central heating system
Fed from an F and E cistern
Modern fully pumped or gravity fed
Sealed pressurised central Heating system
Fed directly from the mains
Expansion/pressure vessel
Usually combi boilers
Gravity hot water/ pumped heating systems
One pipe system
Two pipe ( C plan and C plan +)
C plan (two pipe system)
Gravity circulation to the hot water circuit and pumped circulation to the central heating circuit
Has two pipes( a flow pipe from the boiler to the roads and the return pipe from radiators back to boiler)
One pipe system
Simple ring circuit
No sepárate flow and return pipes
Main ring is pumped and the water circulates through the radiators by gravity circulation
C plan +
Updated c plan
Full thermostatic control of both heating and hot water
Cylinder thermostat and room thermostat
Hot water temp controlled by cylinder thermostat linked to a single two port motorised zone valve installed on gravity flow before it enters the heat exchanger at the hot water storage cylinder
Y plan
3 port motorised mid position valve
Cylinder thermostat and room thermostat
Individual thermostatic radiator valves control temp
The 3 port zone valve controls the flow of water to the primary( cylinder ) circuit and the heating circuit
3 port zone Valve
When the cylinder reaches temperature the valve is energised by a cylinder thermostat, which closes the hot water port, preventing water from flowing to the hot water cylinder heat exchanger
AB heating an hot water
Ball left hot water only water flow B
Ball right central heating only water flow A
W plan
Uses a three port motorised divertir valve
Either the hot water or central heating can be opened
Known as hot water priority system
S plan
Two two port zone valves
System bypass is required for overheat protection of the boiler
