MegafloDirect Hot Water Cylinders

A Megaflo Direct cylinder has no internal heating coil — it relies solely on immersion heaters to heat the stored water, making it ideal for properties without a boiler, such as those on electric-only heating. An indirect cylinder, by contrast, is heated by a coil connected to a boiler or heat source, with immersion heaters as backup. Choosing the wrong type for your heating setup means you'll either have no way to heat the water efficiently or you'll be paying for a coil you never use.

As a rough guide, a 1-bathroom house with 2-3 bedrooms typically suits a 150-180 litre cylinder, while larger homes with two bathrooms or higher occupancy often need 210 litres or more. Because these are direct (immersion-only) cylinders, recovery time is slower than a boiler-fed indirect model, so it's worth sizing up slightly if you have back-to-back bathing or high hot water demand. If you're unsure, we're happy to talk through your household's usage before you buy.

Yes — as unvented hot water storage systems, they fall under Building Regulations Part G3 (or the equivalent Scottish/NI regs), which requires installation and commissioning by a G3-qualified engineer. This covers correct fitting of the expansion vessel, pressure and temperature relief valves, and a properly routed tundish and discharge pipe. Notification to Building Control is also required unless your installer is registered with a competent persons scheme.

Being unvented, these cylinders deliver hot water at mains pressure, so you'll get strong flow to showers and taps without a separate pump. Most models need a minimum incoming mains pressure of around 1.5 bar and adequate flow rate to perform properly — if your supply is marginal, it's worth checking this before installation. Low or inconsistent mains pressure is one of the most common reasons for poor performance after fitting.

Unlike old vented cylinders, Megaflo units don't need a header tank in the loft, so they can be sited in an airing cupboard, utility room, garage or loft space, wherever's most convenient. The location does need to be frost-free and allow access for servicing and for the discharge pipe to run safely to an external outlet. Cylinders are also stood or laid flat depending on the model, so check available space against the specific dimensions before ordering.

Megaflo cylinders typically carry a manufacturer's warranty of around 25 years on the cylinder vessel itself, reflecting the durable stainless steel construction, though electrical components like immersion heaters usually have a shorter cover period. Annual servicing by a qualified engineer is recommended to check the expansion vessel pressure, valves and immersion elements, keeping the system safe and efficient. Keep your commissioning certificate and service records, as these are often required to validate warranty claims.