Heat passes from a boiler or other heat source through an internal coil without mixing that circuit water with the stored domestic water.
Boiler Fed and Solar Ready Hot Water Storage
An indirect cylinder stores domestic hot water while heat is transferred through an internal coil from a separate source. MacBlair lists Warmflow and Albion unvented indirect models, including 120, 150, 180, 210, 250 and 300-litre products on the visible page. A solar-indirect model and a twin-coil unvented option are also listed.
The right choice depends on the heat source, expected draw-off, recovery rate and available space. A twin-coil cylinder is for a system designed to use two heat inputs, while a standard indirect model has a different connection plan. Match the coil arrangement to the boiler and the proposed controls before ordering.
Unvented cylinders also need adequate incoming mains performance and correctly specified safety components. Compare height, diameter and service clearances, then plan the pipe connections and discharge route with a qualified installer. For a busy household, consider how several showers may draw hot water at the same time.
Indirect Water Cylinders FAQs
It can accept heat from two compatible sources where the system and controls are designed for that arrangement.
The cylinder model must be matched to the proposed heat-source design. Check its coil and backup-heating specification.
Size it for peak hot-water use, recovery rate and incoming supply, with advice from the installer.
No. Boiler output, controls, coil performance and safety requirements all need to be checked.