OSO Delta DC150 150L Indirect Unvented Hot Water Cylinder

The OSO Delta DC150 is a 150 litre indirect unvented hot water cylinder designed to deliver high-efficiency mains pressure hot water for modern homes while keeping running costs and heat loss to a minimum.

Using advanced insulation and an A-rated design, this compact cylinder is ideal where energy performance, SAP compliance and space saving are key priorities.

Key Features

• 150 litre indirect unvented hot water cylinder suitable for use with a system or heat-only boiler.
• ErP A-rated efficiency to minimise standing heat losses and support lower energy bills.
• Advanced insulation with NANOPUR / vacuum insulation panel technology for significantly reduced heat loss compared with standard cylinders.
• Mains pressure performance for powerful showers and fast-filling baths when installed on an appropriate cold mains supply.
• High-quality stainless steel construction for durability, corrosion resistance and long service life.
• Factory-supplied unvented control pack including expansion vessel, combination valve, tundish and safety controls for compliant installation.
• Digital thermostat with anti-legionella and holiday modes to optimise performance and hygiene while reducing wasted energy.
• Compact footprint designed to fit a typical UK airing cupboard, helping to maximise usable space.

Why Buy the OSO Delta DC150?

The OSO Delta range is recognised as one of the most efficient unvented hot water cylinder series on the market, helping homeowners and housebuilders meet increasingly strict energy and SAP requirements.

Choosing the DC150 model provides reliable mains pressure hot water, very low heat losses and long-term running cost savings in a compact, installer-friendly package backed by a long manufacturer warranty on the stainless steel tank.

Suitable For

• Small to medium-sized properties with typical hot water demand for 1 bathroom plus additional outlets.
• System or regular boiler installations requiring an indirect unvented hot water cylinder.
• New-build and refurbishment projects where SAP performance and ErP A-rated products are specified.
• Homes upgrading from older vented or lower-rated cylinders to improve efficiency, reduce heat loss and free up space.

Technical Specifications

• Brand: OSO Hotwater
• Range: Delta Coil (Delta DC)
• Model: DC150 / Delta Coil 150 litre indirect unvented cylinder
• Cylinder type: Indirect unvented mains pressure hot water cylinder
• Nominal capacity: 150 litres
• Energy efficiency rating: A (ErP)
• Insulation: High-performance foam with vacuum insulation / NANOPUR technology for ultra-low standing losses
• Installation orientation: Floor-standing
• Height: Approximately 1000 mm (typical for DC150 model)
• Diameter: Approximately 595 mm
• Finish/colour: White outer casing
• Primary heating: Indirect coil for connection to boiler or compatible heat source
• Controls supplied: Unvented control kit including expansion vessel, combination valve, tundish, motorised valve and safety thermostats (indirect)
• Thermostat: Digital control with adjustable setpoint, anti-legionella and holiday functions
• Application: Domestic hot water storage for sealed, unvented systems
• Tank material: High-grade stainless steel for corrosion resistance and long life
• Guarantee: Long manufacturer warranty on tank (up to 25 years on similar OSO Delta stainless steel vessels – check current warranty terms)

Installation & Compliance

The OSO Delta DC150 must be installed and commissioned by a suitably qualified G3-certified installer in accordance with UK Building Regulations, the manufacturer’s instructions and local water authority requirements.

The supplied safety components, expansion vessel and control valves are designed to provide safe, reliable unvented operation when correctly installed, ensuring compliance and long-term performance.