Product Description

OSO Super Coil S2C 300L Indirect Unvented Cylinder

Model: S2C300 | Product Number: 11011676

Combine fast installation with a generous supply of boiler-fed hot water using the OSO Super Coil S2C 300L Indirect Unvented Cylinder. OSO designed this large stainless-steel cylinder for connection to a compatible gas or system boiler.

The smooth 1.1m² internal heating coil transfers energy from the boiler into the stored water. In addition, OSO fits a 3kW Incoloy immersion heater to provide an electric backup when required.

OSO installs the motorised valve, blending valve, safety valves, wiring and much of the required pipework at the factory. It then hides the main components beneath a removable top cover. As a result, the S2C300 offers a neat finish and can reduce installation time.

The model has a nominal size of 300 litres and an actual vessel capacity of 281 litres. It measures 595mm in diameter and 1780mm high.

OSO Super Coil S2C 300L Features

• Large indirect unvented hot water cylinder
• Designed for connection to a compatible boiler
• Part pre-plumbed design when used with a suitable system boiler
• Smooth 1.1m² stainless-steel heating coil
• Primary coil output: up to 23.6kW under the manufacturer’s test conditions
• Approximately 40-minute coil heat-up time under test conditions
• Approximately 28-minute 70% coil recovery time under test conditions
• Factory-fitted 3kW Incoloy backup immersion heater
• Nominal size: 300 litres
• Actual vessel capacity: 281 litres
• Mains-pressure hot water supply
• 24-litre expansion-vessel capacity
• Factory-fitted motorised valve
• Factory-fitted safety and control valves
• Factory-fitted hot water blending valve
• Concealed pipework and wiring
• Top connections hidden beneath a removable lid
• High-grade PUR foam insulation
• Energy efficiency rating: C
• 25-year cylinder warranty, subject to OSO terms
• Model: S2C300
• Product number: 11011676

OSO S2C300 Specification

• View the OSO Super Coil S2C Product Information
• Download the OSO Super Coil S2C Installation Manual
• Brand: OSO Hotwater
• Range: Super Coil S2C
• Model: S2C300
• Product type: indirect unvented hot water cylinder
• Nominal capacity: 300 litres
• Actual vessel capacity: 281 litres
• Usable hot water above 40°C: up to 454 litres under test conditions
• Main heating method: boiler-fed indirect coil
• Primary coil surface area: 1.1m²
• Primary heating output: up to 23.6kW under test conditions
• Primary flow rate used for performance testing: 900 litres per hour
• Primary coil pressure drop: 91mbar under test conditions
• Coil heat-up time: approximately 0.67 hours or 40 minutes
• 70% coil recovery time: approximately 0.47 hours or 28 minutes
• Backup immersion-heater output: 3kW at 240V
• Immersion-heater output at 230V: approximately 2.8kW
• Immersion-heater material: Incoloy 825
• Electrical supply: 230V, 50Hz
• Height: 1780mm
• Diameter: 595mm
• Empty weight: 61kg
• Filled weight: approximately 342kg
• Tank and coil material: stainless steel grade 1.4521
• Insulation: high-grade PUR foam
• Average insulation thickness: approximately 48mm
• Energy efficiency rating: C
• Standing heat loss: 74 watts
• Standing heat loss per 24 hours: approximately 1.77kWh
• Cylinder operating pressure: 3 bar
• Maximum cylinder design pressure: 10 bar
• Heating-coil operating pressure: 2 bar
• Maximum heating-coil design pressure: 10 bar
• Maximum cylinder operating temperature: 85°C
• Maximum heating-coil operating temperature: 99°C
• Expansion-vessel capacity: 1 x 24 litres
• Primary flow connection: 3/4 inch
• Primary return connection: 3/4 inch
• Cold-water connection: 3/4 inch
• Hot-water connection: 3/4 inch
• Ingress protection: IP21
• Product number: 11011676
• GTIN: 7070644010720

What Is Included?

• 1 x OSO Super Coil S2C 300 indirect unvented cylinder
• 1 x Integrated 1.1m² stainless-steel heating coil
• 1 x Factory-fitted 3kW Incoloy backup immersion heater
• 1 x 24-litre expansion vessel
• 1 x Factory-fitted motorised valve
• Factory-fitted pressure-reducing valve
• Factory-fitted expansion-relief valve
• Factory-fitted temperature and pressure relief valve
• Factory-fitted hot water blending valve
• Factory-fitted tundish
• Pre-fitted internal pipework and flexible connections
• Concealed wiring and control connections
• Removable top cover
• First-fix installation template

Always check the current OSO packing list and installation manual when the cylinder arrives.

How Does an Indirect Cylinder Work?

An indirect cylinder uses a boiler to heat the stored domestic water. The boiler sends heated primary water through the cylinder’s internal coil. The coil then transfers that heat into the surrounding stored water.

The boiler water and domestic hot water remain separate. Therefore, water from the heating circuit does not mix with the water supplied to taps and showers.

The S2C300 also includes a 3kW immersion heater. This provides an alternative electric heat source if the boiler is unavailable or when the user needs an emergency backup.

Smooth High-Performance Heating Coil

The S2C300 contains a smooth 1.1m² stainless-steel heating coil. Its smooth surface helps resist limescale build-up while supporting efficient heat transfer.

Under OSO’s stated test conditions, the coil provides up to 23.6kW of primary heating power. It can heat the cylinder in approximately 40 minutes and recover 70% of the stored hot water in approximately 28 minutes.

However, actual performance will depend on the boiler output, primary flow temperature, flow rate, controls and incoming cold-water temperature.

Pre-Plumbed Design for System Boilers

When paired with a compatible system boiler, the S2C becomes a part pre-plumbed hot water solution. OSO factory-fits the motorised valve, main safety valves, controls and much of the required pipework.

Therefore, the installer has fewer separate components to position and connect on site. OSO also supplies a first-fix template, so preparation can begin before the cylinder arrives.

The removable top cover hides the main valves, pipework and wiring after installation. This provides a neat finish while keeping the components accessible for future servicing.

High Hot Water Output

OSO designed the Super Coil range to produce a high volume of usable hot water. The S2C300 stores water at the selected temperature and uses its blending valve to mix it with cold water at the outlet.

Under the manufacturer’s test conditions, the S2C300 can provide up to 454 litres of mixed hot water above 40°C. However, actual output will vary with the stored-water temperature, incoming cold-water temperature, flow rate and blending-valve setting.

The installer must commission the blending valve and confirm safe water temperatures throughout the property.

OSO S2C300 Dimensions

• Overall height: 1780mm
• Overall diameter: 595mm
• Empty weight: 61kg
• Approximate filled weight: 342kg

Allow extra space above and around the cylinder for primary pipework, discharge connections, electrical wiring, the expansion vessel, servicing and removal of the top cover. Always use the current OSO technical drawing when planning the installation area.

Suitable Applications

• Compatible gas boiler systems
• Compatible system boilers
• Larger homes that require mains-pressure hot water
• Properties with several bathrooms or hot water outlets
• Properties without a cold-water storage tank in the loft
• Replacement indirect unvented-cylinder installations
• New heating and hot water systems

This cylinder uses a conventional boiler coil. Therefore, do not select it for an air source or ground source heat pump unless OSO and the system designer confirm suitability.

Installation Requirements

• Installation must comply with Building Regulations Approved Document G3
• A qualified and competent unvented-cylinder installer must complete the work
• A qualified heating engineer must connect and commission the boiler circuit
• A qualified electrician must complete the electrical connections
• The installer must test the incoming mains pressure and flow rate
• The boiler and controls must suit the cylinder specification
• The supporting floor must carry the full operating weight
• The safety-valve discharge pipework must follow current regulations
• The tundish must remain visible after installation
• The installer must provide suitable servicing access
• The cylinder must remain upright during installation and operation
• The complete system must be commissioned before use
• Follow the current OSO installation manual in full

This is an unvented hot water cylinder. Therefore, it must not be installed as a general DIY product.

Check Before Ordering

• Confirm that a 300-litre cylinder suits the property and expected demand
• Check that an indirect cylinder matches the heating-system design
• Confirm that the boiler output suits the 1.1m² cylinder coil
• Do not confuse this model with an S2X direct electric cylinder
• Measure the installation space and full delivery route
• Allow room above the cylinder to remove the top cover
• Allow suitable space for the 24-litre expansion vessel
• Confirm that the supporting floor can carry the filled cylinder
• Check the incoming mains pressure and flow rate
• Plan a compliant route for the safety discharge pipework
• Ask the installer to approve the cylinder before ordering

OSO Super Coil Warranty

OSO offers a 25-year warranty on the cylinder, subject to its current terms and conditions. Separate warranty periods may apply to the immersion heater, valves, motorised valve, controls and other components.

Correct installation, commissioning, annual servicing and product registration may affect warranty cover. Therefore, keep your invoice, commissioning records and service history. You should also follow OSO’s current warranty requirements.

Why Buy from SNH Tradecentre?

SNH Tradecentre supplies unvented hot water cylinders and installation components to homeowners, landlords, developers and professional installers across the UK.

Our experienced team can help you check the cylinder type, dimensions and basic specification before you order. We can also help identify the additional fittings that your installation may require.

If you need advice about the OSO Super Coil S2C300, call us on 01843 842727 or visit our trade counter in Birchington, Kent.