500 Litre Direct Unvented Cylinder

Our 500 Litre direct unvented cylinder is built with corrosion-resistant duplex stainless steel and is at an affordable price. This unvented hot water cylinder for mains pressure hot water uses proven technology and quality production to provide high flow rates and a long product life.

Flexiheat UK warranties this 500 Litre stainless steel unvented direct cylinder for 25 years for household use. Hot water cylinders heated by 100% energy-efficient immersion heaters (100% heat transmission) heat bathrooms and showers.

Direct types are utilised when gas or oil is unavailable, a heat pump is unviable, or people desire carbon-free electricity to heat their water.

This electric powered 500 litre unvented hot water storage cylinder is made from stainless steel making them suitable for hard and soft water areas of the UK.

This water heater can be powered PV solar panels (photovoltaics) which produce solar electricity for off grid or carbon free power. An inverter is required for the immersions – to convert DC to AC to power the immersions correctly.

Patented unvented hot water expansion system

The innovative internal hot water expansion mechanism, which employs a venturi valve to keep an air pocket within the stainless steel cylinder, eliminates the need for an external expansion vessel.

 

Our direct unvented hot water cylinders have an internal air gap and venturi valve technology that requires no expansion vessel and little maintenance.

Without moving parts, this unvented system provides a long product life and minimal operating and lifetime costs.

Internal air gap system for our direct unvented hot water cylinders: no external expansion vessel is needed because this self-sustaining air gap requires little to no maintenance and ensures mains pressure hot water flow throughout the property regardless of the heat source.

Our direct unvented hot water cylinders use an internal air gap and venturi valve technology to eliminate the need for an expansion vessel and reduce maintenance.

Our 500-litre electric hot water system requires less space, pipes, and plumbing connections, simplifying installation and saving time and money.

What applications is a 500L direct unvented cylinder appropriate for?

500 litre direct unvented hot water cylinders are suitable for 4-bedroom homes with two bathrooms/showers or more or those with a high hot water demand.

However, hot water usage preferences vary.

See our 500L unvented direct cylinder recovery time data below to decide if this electric water heater is best for you.

This 500 Litre volume direct unvented cylinder is a popular seller in this range; however, if you require a higher volume cylinder, please visit the following webpage: direct unvented cylinder range.

Hot water heating and recovery times for a our direct unvented cylinder 500 Litres from Flexiheat UK

High-quality stainless steel 500 Litre direct-pressurised hot water cylinders include 2 x 3kW immersion heaters.

The typical 2 x 3kW immersion heaters in our 500 Litre unvented electric powered direct cylinder provide the following hot water heat-up and recovery rates:

 

Our 80 to 500 litre direct unvented hot water cylinders are listed on this page: Unvented Direct Cylinder in Stainless Steel.

Upgraded immersion heater options.

On both the 2 and 3 immersion models, we can increase immersion heater outputs for faster heat recovery.

Three 3 kW immersion electric heaters can be added to this 500-litre direct unvented cylinder for a total of 9 kW and 214 minutes from 10°C to 65°C.

We can supply this 500 Ltr direct unvented cylinder with 3 x 6 kW immersion heaters. These heaters can output 18 kW from a single phase at 240 volts (32 amps per heater) or three phases (10.66 amps per phase). This method heats 500 litres of water from 10°C to 65°C in 107 minutes.

Since the standard temperature and pressure relief valve is rated for 10kW, we must upgrade it.

Our manufacture tests all unvented hot water cylinders at 5.5 bar and 10 bar.

If you want a bigger output of up to 36 kW for a 500 Litre direct water heater, please consult this webpage: Commercial electric water heater range.

Unvented Direct Cylinder 500 Litres: Features and Benefits.

Unvented cylinders’ internal air gap is automatically supplied by improved Venturi valve technology.

The standard dual immersion cylinder has 2 x 3 kW immersion heaters, which can be increased to 3 × 3 kW or 3 × 6 kW.

Our straight unvented hot water cylinders with inbuilt expansion require no external expansion vessels.

Our integrated expansion mechanism straight unvented hot water cylinders don’t need extra expansion vessels, making installation in tight spaces easier.

 

• 3-bar water pressure at the outflow (subject to entering pressure)
• Direct distribution of hot water under mains pressure enables high flow rates.
• 100% Heat transfer with electric immersion heaters
• There is no expansion vessel or moving parts, which ensures minimum maintenance.
• ErP “C” heat loss rating indicates lower energy heat loss and consumption.
• Premium appearance units with a P200 Plastisol outer casing
• Benefits from an updated design and high-quality manufacture for better performance at low flows.
• Our 500 litre direct electric unvented cylinder includes a DHW secondary tapping return connection.
• This 500l electric hot water system comes standard with 22mm connectors (which produce 40 litres per minute), but it may also be ordered with a 28mm-diameter stainless steel inlet and output for higher flow rates (56 litres per minute).
• This 500 Litre unvented direct hot water cylinder includes 60mm of fire retardant insulation to decrease heat loss.

Dimensions for a 500-litre unvented direct cylinder

Our 500-litre stainless steel direct unvented cylinder has the following dimensions:

 

The dimensions in millimetres for the corrosion-resistant duplex stainless steel 500 Ltr capacity direct unvented cylinder are as follows:

 

 

500L direct cylinder with internal expansion dimensions

The full brochure and installation manuals are here (Which cover both the direct models and indirect models ) :

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

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

Unvented Cylinder Certifications for our 500 litre unvented indirect cylinders

Our 500 Ltr direct unvented cylinder has been certified by CE, BBA, and WRAS, independent organisations that ensure hot water heating products are safe and compliant, in addition to ISO, KIWA, and WRC certifications.

Warranty for the 500 Litre Hot Water Cylinder

For domestic use in homes and apartments, our 500 Litre unvented direct cylinders have a 25-year warranty because we trust them. Immersion heaters and control thermostats are insured for one year after purchase, however the stainless steel hot water cylinder is guaranteed for 25 years.

Contact Flexiheat UK

Please contact us at 01202 822221 if you have any queries or use site contact email form for more information or specifics, the current stock situation, or a price on the best 500 litre direct unvented cylinder/500Ltr unvented direct cylinder model on the UK market. We manufacturer these models from high-grade duplex stainless steel, which has a 25-year warranty for residential customers (5 years for commercial use), a low heat loss rating, and WRAS independent approvals.