The Megaflo Main 150 Litre Indirect Unvented Hot Water Cylinder (7912278) is a UK-manufactured stainless steel cylinder designed to provide reliable mains-pressure hot water heated indirectly by a gas, oil or system boiler. With a factory-fitted 3.0kW Incoloy 800 immersion heater for backup heating, this 150-litre cylinder is well suited to small to medium homes with one or two bathrooms requiring dependable hot water delivery.
The Megaflo Main is the new name for the Main unvented cylinder range and replaces the previous Main 150 Litre Indirect Unvented Hot Water Cylinder (5133562). Featuring a unique coil-in-coil heat exchanger, 50mm factory-injected polyurethane insulation and factory-fitted safety controls, this cylinder is designed to provide rapid heat recovery while helping minimise heat loss.
150L Capacity
Indirect Unvented
12.5kW Coil
Incoloy 800 Immersion
25-Year Vessel Warranty
Key Benefits at a Glance
12.5kW
Primary Coil Rating
55L/min
Maximum Flow Rate
25 Years
Inner Vessel Warranty
Applications & Suitability
- Small to medium homes requiring 150 litres of mains-pressure hot water storage.
- Properties with one or two bathrooms requiring reliable domestic hot water.
- Domestic hot water systems using a gas, oil or system boiler as the primary heat source.
- Installations requiring an indirect unvented hot water cylinder with backup immersion heating.
- Heating upgrades using Main Eco Compact System or Main Eco Elite System boilers.
- Projects requiring KIWA approval and Building Regulation G3 compliance.
Key Specifications
| Product Code |
7912278 |
| Type |
Indirect Unvented |
| Nominal Capacity |
150 Litres |
| Height (A) |
1114 mm |
| Diameter |
Ø 550 mm cylinder / 595 mm base |
| Weight (Empty) |
32 kg |
| Primary Coil |
22mm stainless steel coil-in-coil heat exchanger |
| Coil Rating |
12.5 kW |
| Coil Heat-Up Time |
38 minutes |
| Recovery Time |
24 minutes |
| Immersion Heater |
1 × 3.0kW Incoloy 800 @ 240V |
| Inner Vessel |
High-grade stainless steel |
| Pressure Tested |
15 bar |
| Operating Pressure |
3.5 bar |
| Maximum Flow Rate |
Up to 55 l/min @ 6 bar |
| Insulation |
50mm CFC/HCFC-free polyurethane foam |
| Standing Heat Loss |
1.70 kWh/24h |
| ErP Energy Rating |
C |
| Thermostat |
Adjustable 10–70°C with 80°C high-limit |
| Connections |
22mm compression / ¾" BSP |
| Expansion Vessel |
12 litre, supplied |
| Manufacturer |
Baxi, UK manufactured |
| Warranty |
25 years stainless steel inner vessel; 1 year parts & labour |
Indirect Heating & Rapid Heat Recovery
The Megaflo Main 150 Litre uses a 22mm stainless steel coil-in-coil heat exchanger with a 12.5kW rating to heat the stored domestic hot water indirectly from a compatible gas, oil or system boiler. The stated coil heat-up time is 38 minutes, with a recovery time of 24 minutes.
A factory-fitted 3.0kW Incoloy 800 immersion heater provides backup heating when required. The immersion element is rated at 240V and forms part of the factory-fitted cylinder configuration.
Insulation, Safety & Factory-Fitted Components
50mm Insulation
Factory-injected 50mm CFC/HCFC-free polyurethane foam helps minimise heat loss, with standing heat loss specified at 1.70 kWh/24h.
Safety Protection
Supplied with a T&P relief valve, pressure reducing valve and 2-port motorised valve for primary over-temperature protection.
12L Expansion Vessel
A 12-litre expansion vessel is supplied with the cylinder as part of the specified system components.
Factory-Fitted Controls
The cylinder is supplied with factory-fitted controls alongside the specified safety and pressure-management components.
Approvals & Compliance
The Megaflo Main 150 Litre Indirect Unvented Hot Water Cylinder is KIWA approved for compliance with Water Regulations and is compliant with Building Regulation G3. It is also CE marked.
The high-grade stainless steel inner vessel is pressure tested to 15 bar, while the stated operating pressure is 3.5 bar. The adjustable thermostat operates from 10–70°C with an 80°C high-limit.
Supplied Components
- 12 litre expansion vessel
- T&P relief valve
- 2-port motorised valve
- Pressure reducing valve
- Factory-fitted controls
- Factory-fitted 3.0kW Incoloy 800 immersion heater
Ideal For
- Small to medium homes with one or two bathrooms.
- Domestic hot water systems using gas, oil or system boilers.
- Installations requiring 150-litre mains-pressure hot water storage.
- Heating upgrades using Main Eco Compact System boilers.
- Heating upgrades using Main Eco Elite System boilers.
- Domestic systems requiring backup immersion heating and reliable hot water delivery.
Frequently Asked Questions
What is the capacity of the Megaflo Main 150 Litre cylinder?
The cylinder has a 150-litre nominal capacity and is designed to provide mains-pressure domestic hot water.
Is the Megaflo Main 150 Litre cylinder indirect?
Yes. It is an indirect unvented hot water cylinder that uses a 12.5kW coil-in-coil heat exchanger to heat the stored water from a compatible gas, oil or system boiler.
What backup heating does the cylinder have?
The cylinder has one factory-fitted 3.0kW Incoloy 800 immersion heater rated at 240V for backup heating.
What is the operating pressure?
The stated operating pressure is 3.5 bar, while the stainless steel inner vessel is pressure tested to 15 bar.
What warranty is included?
The stainless steel inner vessel is covered by a 25-year warranty, with an additional 1-year parts and labour warranty.
Which boilers can the Megaflo Main cylinder pair with?
The cylinder is designed for indirect heating from a gas, oil or system boiler. It pairs with the Main Eco Compact System and Main Eco Elite System boilers for a complete domestic hot water solution.
What are the dimensions of the 150 Litre cylinder?
The stated height is 1114mm. The cylinder diameter is 550mm, with a base diameter of 595mm. The empty weight is 32kg.
Megaflo Main 150 Litre Indirect Unvented Cylinder – Reliable Mains-Pressure Hot Water
The Megaflo Main 150 Litre Indirect Unvented Hot Water Cylinder (7912278) combines 150-litre storage with a 12.5kW coil-in-coil heat exchanger, 3.0kW Incoloy 800 backup immersion heater, 50mm polyurethane insulation and factory-fitted safety components. With a 25-year stainless steel inner vessel warranty, KIWA approval and Building Regulation G3 compliance, it is a practical choice for small to medium homes with one or two bathrooms. Order online from GetPlumb for UK delivery or collect from the Reading trade counter.
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