Megaflo Main is the new name for the Main unvented cylinder range. This model replaces the Main 300 Litre Direct Unvented Hot Water Cylinder (720636401). Supplied as two boxes: cylinder plus fitting kit (90001992).
The cylinder features a high-grade stainless steel inner vessel, 50mm of factory-injected CFC/HCFC-free polyurethane foam insulation and a 24-litre expansion vessel. The adjustable thermostat, factory-fitted controls and supplied unvented safety components provide a complete solution for direct hot water storage.
300L Capacity
Direct Unvented
2 × 3kW Immersions
25-Year Vessel Warranty
300 Litre Storage
Large-capacity hot water storage designed for high-demand domestic applications.
Dual Immersion Heating
Two 3.0kW Incoloy 800 immersion heaters provide direct electric water heating.
50mm Insulation
Factory-injected CFC/HCFC-free polyurethane foam helps minimise standing heat loss.
High-Grade Stainless Steel
Pressure-tested stainless steel inner vessel designed for dependable hot water storage.
Applications & suitability
Large Homes
The 300-litre capacity is suited to properties with high domestic hot water demand.
Multiple Bathrooms
Provides substantial stored hot water capacity for properties with multiple bathrooms.
Off-Grid Properties
Direct electric heating makes the cylinder suitable for properties without access to mains gas.
Solar PV & Off-Peak Tariffs
Suitable for installations using solar PV generation or off-peak electricity tariffs.
Key specifications
| Product Code |
7912288 |
| Type |
Direct Unvented |
| Nominal Capacity |
300 Litres |
| Height (A) |
2065 mm |
| Diameter |
Ø 550 mm (cylinder) / 595 mm (base) |
| Weight (Empty) |
55 kg |
| Immersion Rating |
2 × 3.0 kW @ 240V |
| Heat-Up Time |
315 mins |
| Standing Heat Loss |
2.52 kWh/24h |
| ErP Energy Rating |
D |
| Operating Pressure |
3.5 bar |
| Expansion Vessel |
24 litre (supplied) |
| Connections |
22mm compression / ¾" BSP |
| Packaging |
Two boxes: cylinder plus fitting kit (90001992) |
Installation & compatibility
The Megaflo Main 300 Litre Direct Unvented Cylinder is designed for direct electric water heating using its two factory-fitted Incoloy 800 immersion heaters. It is supplied with a 24-litre expansion vessel, T&P relief valve, pressure reducing valve and factory-fitted controls. The cylinder is also suitable for installations using solar PV systems and off-peak electricity tariffs.
Design & performance benefits
Dual Immersion Heating
Two 3.0kW Incoloy 800 immersion heaters provide a combined 6.0kW direct heating capacity.
Stainless Steel Inner Vessel
The high-grade stainless steel inner vessel is pressure tested to 15 bar.
Factory-Injected Insulation
50mm CFC/HCFC-free polyurethane foam insulation helps reduce standing heat loss.
Adjustable Thermostat
Thermostat adjustment from 10–70°C with an 80°C high-limit cut-out.
Additional installation features
24L Expansion Vessel
A 24-litre expansion vessel is supplied as part of the cylinder package.
Factory-Fitted Controls
Factory-fitted controls help provide a ready-to-install unvented cylinder system.
KIWA & G3 Compliance
KIWA approved, Building Regulation G3 compliant and CE marked.
Ideal for
Very Large Homes
300 litres of stored hot water for properties with substantial domestic hot water requirements.
Multiple-Bathroom Properties
Large storage capacity for homes where hot water demand can be high.
Off-Grid Applications
Direct electric heating makes it suitable for properties without mains gas.
Solar PV & Off-Peak Systems
Designed for use with solar PV generation and off-peak electricity tariffs.
The Megaflo Main 300 Litre Direct Unvented Hot Water Cylinder combines high-capacity 300-litre storage, dual Incoloy 800 immersion heating, stainless steel construction and comprehensive unvented components. With its 25-year stainless steel inner vessel warranty and 1-year parts and labour warranty, it provides a robust solution for high-demand domestic hot water installations. Order now for a complete direct unvented hot water storage solution.
