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Upgrade nowOpen Vented Central Heating Systems
Read through the material below, then test your understanding.
Module Lessons
Central Heating
Introduction to Central Heating & Part L
Heat Emitters: Radiators and Convectors
Radiator Valves: TRVs and Lockshields
System Layouts: One-Pipe and Two-Pipe
System Layouts: Microbore and Manifold
Boiler Types: Regular, System, and Combination
Condensing Boiler Principles
Open Vented Central Heating Systems
Sealed Central Heating Systems
Expansion Vessels and Pressure Relief
Central Heating Pumps and Circulators
System Controls: Programmers and Thermostats
Motorised Valves: 2-Port and 3-Port
Fully Pumped Systems: The Y-Plan
Fully Pumped Systems: The S-Plan
Filling, Venting, and System Balancing
Water Treatment and System Protection
Lesson Overview
An open vented central heating system operates at low pressure and is open to the atmosphere via a feed and expansion cistern and a safety vent pipe. This design naturally accommodates water expansion and prevents dangerous over-pressurisation.
Learning Objectives
Identify the key components, pipework layouts, and operational principles of an open vented central heating system.
Explain the sizing, installation, and safety requirements for the feed and expansion cistern, cold feed, and primary open vent.
Describe the neutral point, pump positioning, and the causes and prevention of pumping over and system aeration.
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