OSO Maxi GeoCoil MGC400 400L Heat Pump Cylinder | High Capacity 15kW 3-Phase Unvented Hot Water Storage

The OSO Maxi GeoCoil MGC400 is a 400 litre unvented heat pump cylinder optimised for maximum hot water production from heat pumps up to 25 kW (with larger models up to 40 kW). Featuring 3.1 m² large smooth scale-resistant titanium alloy coil and superior vacuum insulation panel (VIP) and NANOPUR foam insulation, it delivers ultra-efficient, rapid recovery and low heat loss.

Key Features

• 400 litre capacity provides high-volume hot water storage for large homes and commercial properties.
• High heat pump compatibility up to 25 kW ensures maximum efficiency and flexible system integration.
• Advanced insulation technology combining VIP and NANOPUR foam for minimal standing heat loss, saving up to 650 kWh/year.
• 3.1 m² smooth scale-resistant primary coil designed for rapid heat transfer and durability in hard water areas.
• 3-phase 15 kW electric immersion heater option for high power backup and quick recovery times.
• Adjustable thermostat (60-90°C) with anti-legionella and holiday modes for optimal hygiene and energy savings.
• Compact diameter 595 mm but tall 2170 mm height designed to fit standard airing cupboards while maximising capacity.
• Factory-fitted comprehensive unvented control pack including expansion vessel, safety valves, motorised valve and temperature controls.

Why Buy the OSO Maxi GeoCoil MGC400?

This cylinder is built for maximum hot water production and energy efficiency, ideal for large residential buildings or commercial applications requiring high capacity and rapid recovery combined with compliance to the strictest building and energy regulations.

The use of high-grade materials and advanced insulation ensures long service life and significantly reduced operating costs.

Suitable For

• Large homes and light commercial properties with high hot water requirements.
• Heat pump systems up to 25 kW needing large capacity indirect unvented cylinders.
• New build and retrofit projects requiring future-proofed, high-efficiency hot water solutions.
• Installations needing 3-phase electric immersion backup for rapid hot water availability.

Technical Specifications

• Brand: OSO Hotwater
• Model: Maxi GeoCoil MGC400 (Product code: 11008988)
• Type: Indirect unvented heat pump cylinder
• Capacity: 400 litres
• Heat Pump Compatibility: Up to 25 kW
• Energy Rating: A (ErP)
• Primary Coil Size: 3.1 m² smooth scale-resistant titanium alloy
• Dimensions: Diameter 595 mm x Height 2170 mm
• Weight: Approx. 101 kg empty
• Immersion Heater: 15 kW 3-phase (optional)
• Standing Heat Loss: Low heat loss from VIP + foam insulation
• Thermostat: Adjustable 60-90°C with anti-legionella & holiday modes
• Expansion Vessel: Included in control pack
• Warranty: 25 years tank / 2 years components

Installation & Compliance

Supplied complete with a full G3-compliant unvented control pack to ensure safe, efficient installation by qualified professionals, including all safety valves, expansion vessel, and controls for professional heat pump integration.