300 Litre direct unvented cylinder

Our 300 litre direct unvented cylinder is engineered in corrosion-resistant duplex stainless steel and is a competitively priced cylinder. We designed it to achieve high flow rates and a long product life using proven technology and a quality manufacturing process for this unvented hot water cylinder for mains pressure hot water.

When gas is unavailable or when people prefer to use carbon-free electricity sources for water heating, they frequently use electric water heating.

Patented unvented hot water expansion system

The patented internal hot water expansion system, which uses a venturi valve to maintain an air pocket within the stainless steel cylinder, eliminates the need for an external expansion vessel.

This unvented system has a long product life because it has no moving parts, which reduces running and lifetime costs.

 

As a result, our 300 Ltr direct unvented cylinder need less space, pipework and plumbing fittings, making the installation simpler and lowering both costs and time required for installation.

What is a 300L direct unvented cylinder suitable for?

A rough guide is that 300 litre direct unvented hot water cylinders are suitable for larger homes, typically a 4-bedroom house with 2 bathrooms/showers or larger, or for properties with a high demand for hot water.

However, people’s hot water usage patterns can vary from household to household. We prefer to give you the hot water usage data, and you decide if it suits your hot water needs.

In the United Kingdom, we are required to keep DHW at 60°C since it eliminates the possibility of Legionella disease and is the minimum recommended storage water temperature for the UK.

If the stored water temperature is 60°C, the amount of required water is in red, to be blended down to 43°C (the maximum bathing temperature before scalding can occur).

Please use 10°C for England and Wales as the lowest cold-water wintertime temperature and use 5°C for Scotland and Northern Ireland.

If the incoming cold-water temperature                                is 10°C                                is 5°C

A bath uses around 135 litres of water at 43°C                    89 litres                               94 litres

A standard 8-litre shower head x 5 minutes                         30 litres                               31 litres

And yes, 5 minutes is the average showering time—say all the time and motion studies report.

A kitchen sink holds up to 20 litres of water                        16 litres                                 16.5 litres

To ensure the removal of grease from dishes and cooking utensils, the standard temperature for washing up water is 50°C.

Toilet sink taps—standard type—are around 4 litres per minute; “spray” type taps are 2 litres per minute and tend to be on for a brief period.

Please see the recovery time data below for our 300 Litre direct unvented cylinder to establish if this the correct 300 litre electric water heater for your circumstances and demands.

This 300 Litre volume direct unvented cylinder is a popular seller in this range, however, should you wish a larger volume cylinder, then please see the following webpage – direct unvented cylinder range

Hot water heat-up time and recovery rates for our direct unvented cylinder, 300 litres in capacity

As standard, our 300 litre direct-pressurised hot water cylinders in high-grade stainless steel are fitted with 2 x 3kW immersion heaters with proven technology and quality.

Our 300 Litre unvented indirect cylinder has the following hot water heat-up time and recovery rates with standard 2 x 3kW immersions fitted:

Should you require another size direct unvented hot water cylinder, then we do a full range from 80 to 500 Litres, which are detailed on this webpage – Unvented Direct Cylinder in stainless steel range.

Upgraded immersion heater options 

We have the option of upgrading the immersion heaters to larger outputs for quicker heat recovery on both the 2 and 3 immersion model options.

This 300 litre direct unvented cylinder can also be supplied with 3 x 3 kW immersion electric heaters – giving a total kW output of 9 kW, with a recovery time from 10°C to 65°C of 130 minutes (or 2.17 hours).

We can provide this 300 Ltr direct unvented cylinder with 3 x 6 kW immersion heaters if requested. These heaters can be connected to either a single phase at 240 volts (which needs 32 amps for each heater) or three phases (which needs 10.66 amps for each phase), resulting in a total power of 18 kW. This setup allows the water to heat from cold (10°C) to 65°C in 66 minutes for the 305 litres of water stored.

We also must upgrade the standard temperature and pressure relief valve to a larger output model, as the standard temperature and pressure relief valve is rated to 10kW of output.

All of our unvented hot water cylinders have a pressure test at the factory, and all are tested to 10 bar pressure and have a maximum working pressure of 5.5 bar.

Should you wish to have a larger output of up to 36 kW for a 300 Litre direct water heater, then please see this webpage – Commercial electric water heater range

Unvented Direct Cylinder 300 Litres: Features and Benefits

• Enhanced Venturi valve technology, which automatically replenishes the internal air gap within the unvented cylinder.
• Dual immersion cylinder: 2 x 3 kW immersion heaters as standard, with the option of 3 × 3 kW immersion heaters or 3 × 6 kW immersion heaters like so.

• 3 bars of water pressure at the outlet (subject to incoming pressure)
• Direct delivery of hot water under mains pressure allows for high flow rates.
• No expansion vessel or moving parts, ensuring low maintenance.
• ErP “C” heat loss rating for reduced energy heat loss and consumption.
• Benefits from an evolved design and quality manufacturing for improved performance at low flow rates.
• Our 300 litre direct unvented cylinder comes with a DHW secondary return connection.
• As standard, it comes with 22mm connections (which will produce 40 Litre per minute), but it is also available with a 28mm-diameter stainless steel inlet and outlet for high flow rates ( 56 Litres per minute).
• This unvented hot water cylinder has 60mm fire retardant insulation for reduced heat loss.

300 litre unvented direct cylinder dimensions

Our 300 litre stainless steel direct unvented cylinder has the following dimensions:

The highly corrosion-resistant duplex stainless steel 300 Ltr capacity direct unvented cylinder has the following dimensions in mm:

The full brochure and installation manuals are here – 

Download the Hot water cylinders direct and indirect unvented brochure from Flexiheat UK

Download the installation & technical manual for our direct and indirect hot water cylinders

Unvented direct cylinder 300 ltr approvals

The 300 ltr direct unvented cylinder we sell has been certified by CE, BBA, and WRAS, which are independent organisations that ensure hot water heating products are safe and meet regulations, and it also has ISO, KIWA, and WRC certifications, showing that our stainless steel cylinders are made with high-quality standards.

Warranty of the 300 Litre hot water cylinder

We’re so sure of the quality of our 300 litre unvented direct cylinder that they come with a 25-year warranty for use in residential locations like homes, apartments, and so on. The warranty covers the stainless steel hot water cylinder for 25 years, while the other parts, like the immersion heaters, control thermostats, and so on, are covered for one year from the date of purchase, subject to conditions.

Contact Flexiheat UK

Please contact us at 01202 822221 to answer any questions or use the company site contact email form to get further information or details, the current stock situation, delivery options, or a cost on the best 300 litre direct unvented cylinder/300Ltr unvented direct cylinder models on the UK market. We manufacture these models from high-grade duplex stainless steel, which comes with a 25-year warranty for domestic use (5 year warranty for commercial use) , a low heat loss rating and WRAS independent approvals.We sell direct to both end users and trade customers.