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Upgrade nowExpansion Vessels and Pressure Relief
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
Sealed central heating systems rely on an expansion vessel and a pressure relief valve to manage the thermal expansion of water safely. These components eliminate the need for an open feed and expansion cistern in the roof space.
Learning Objectives
Explain the purpose, operating principle, and internal construction of an expansion vessel.
Identify the function, typical pressure rating, and discharge pipe requirements of a pressure relief valve.
Describe the correct procedures for checking, maintaining, and diagnosing faults on sealed system pressure components.
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