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Upgrade nowSecondary Circulation Systems
Read through the material below, then test your understanding.
Module Lessons
Hot Water Systems: Planning & Design
Fuels Used in Hot Water Systems
Open Vented Storage Systems
Unvented Storage Systems
Localised Water Heaters
Unvented System Pressures
Secondary Circulation Systems
Hot Water Safety Controls
Functional Controls: Strainers & PRVs
Expansion Devices & Check Valves
Pressure Relief, Tundish & Composite Valves
Discharge Pipework: Sizing & Termination
Design Information Sources
Sizing Cisterns & Storage Vessels
Hot Water Pipework Sizing
Sizing Circulation & Boosting Pumps
Sizing Expansion Vessels & Presenting Designs
Installing Unvented Hot Water Systems
Testing & Commissioning Hot Water Systems
Diagnosing Hot Water System Faults
Component Fault-Finding: Pumps, Vessels & Thermostats
Servicing & Maintaining Hot Water Systems
Lesson Overview
Secondary circulation provides instant hot water to outlets, eliminating excessive dead legs and reducing water wastage in large dwellings.
Learning Objectives
Identify the statutory maximum dead leg pipe lengths and volume limits for hot water installations.
Explain the layout, component positioning, and backflow requirements for open vented and unvented secondary return circuits.
Specify correct operating temperatures, pump body materials, and control strategies to prevent Legionella growth and heat loss.
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