210 Litre indirect unvented cylinder

Our 210 litre indirect unvented cylinder is the best and most competitively priced cylinder on the UK market, manufactured in stainless steel with proven technology and quality manufacturing for maximum life with the capacity to supply mains pressure hot water for your bathroom, shower, wet rooms, and kitchen tap hot water demands in domestic properties via a domestic hot water sealed system.

Conventional boiler powered

This indirect unvented cylinder is “indirect,” meaning that the cylinder has a coil within the inner cylinder, which needs to be connected and fed by a conventional boiler or traditional boiler, be it an electric boiler, gas or oil boilers.

Being an unvented water storage cylinder, you cannot use solid fuel boilers as the heat source. You must use a vented cylinder for solid fuel boilers, that has a vent pipe to account for the DHW expansion.

Unvented hot water storage tank

Our 210 Litre indirect unvented hot water cylinder does not require an external expansion vessel, as it uses a patented self-sustaining internal air gap within the cylinder to account for the hot water expansion pressure that requires minimum to no maintenance.

What is an unvented indirect cylinder?

A 210 ltr unvented indirect cylinder receives its supply directly from the mains water supply directly, allowing it to produce hot water at a significantly higher pressure than a traditional vented cylinder due to its pressurisation.

An indirect unvented cylinder is a type of hot water cylinder that uses a primary coil to heat water indirectly, providing a safe and efficient hot water supply.

Indirect unvented cylinders are designed to work with a boiler as a heat source, providing a reliable and efficient domestic hot water supply.

What hot water demand is a 210L indirect hot water cylinder suitable for?

The overall amount of hot water used is also greatly influenced by individual behaviours. The amount of hot water used by two houses of the same size might range greatly, with one household needing twice as much as the other.

Understanding peak demands and making sure you have the ideal ratio of cylinder capacity to reheat times are the most important factors.

As a general guideline, use the following average consumption values for hot water requirements per person per day:

• Low Consumption: 20–30 litres

• Average consumption: 30–50 litres.

• High consumption: 50–70 litres

source – hotwater.org.uk

Generally, a 3-bedroom property with multiple bathrooms i.e. 1 or 2 baths or showers should utilise a 210L unvented indirect cylinder.

Although if the household is a high-water user, then you should look at the next volume size up cylinder, our 250 Litre unvented indirect cylinder, which is detailed on this webpage – 250 Litre indirect unvented cylinder.

The product offers key specifications, features, and benefits

• Made from highly corrosion-resistant duplex stainless steel, these 210L unvented indirect models ensure a long product life and minimal maintenance.
• Note: no sacrificial anode is required for a stainless-steel unvented cylinder.
• We manufacture and certify our units in accordance with the BBA, CE, KIWA, ISO, NSF WRC, and WRAS independent approvals.
• The full benefit of quality manufacturing and proven technologies at a competitive price.
• We use a stainless-steel indirect heating coil (a heat exchanger) to speed up heat transfer, minimise heat loss, and enable high flow rates. This corrugated coil heat exchanger provides faster reheat times compared to standard plain tube coils.
• We use 60 mm thermal insulation to reduce heat loss – we use reduced heat loss manufactured factory-injected polyurethane foam insulation bonded onto our highly corrosion-resistant duplex stainless steel tank on our 210-litre cylinder to minimise heat loss and running costs. This high-grade insulation is HCFC/CFC free (ODP=0, GWP=1).
• Minimal heat loss: Because these units have an ErP rating, they lose less heat, which is better for the environment.
• It comes standard with a 3 kW immersion heater. This immersion heater is made from Incoloy for long durability that can be used for additional off-peak immersion heating, top-up or emergency water heating should the gas or oil conventional boiler fail.
• The factory set pressure relief valve ensures a safe and efficient operation of these stainless steel indirect water heaters.
• Features a secondary return for a DHW recirculation system if required
• It offers high flow rates for showers and baths in both residential and commercial settings at a maximum inlet pressure of 3.5 bar, eliminating the requirement for a booster pump.

Our 210 litre indirect unvented hot water cylinders are manufactured from duplex stainless steel and thus don’t require a sacrificial anode, which results in less maintenance time and costs for our 210 litre indirect unvented cylinders.

Our indirect unvented cylinder range allows for installation in smaller spaces because it doesn’t require an external expansion vessel. On the left is our indirect unvented cylinder with no expansion vessel installed, and on the right is an indirect cylinder with an external expansion vessel system, which requires a lot more space for the associated pipe work and connections.

 

Hot water cylinder detail for our 210 Litre unvented indirect cylinder

First we have the dimensions of our indirect unvented cylinder, 210 litres in capacity.

 

Dimension data in “mm” for the above specification diagram

 

The below heat exchanger coil output (kW) is based on a flow temperature of 85°C. If you require higher outputs, then please see our indirect high recovery cylinder range.

 

Download the Indirect and direct hot water cylinders in stainless steel brochure from Flexiheat UK

Download the  Installation and maintenance manual for Flexiheat UK indirect and direct hot water cylinders

 

Standard supplied indirect hot water cylinder unvented components

• Temperature/Pressure Safety Relief Valve: set at 90°C and 7 bar pressure (factory fitted to the indirect unvented cylinder)
• The combination (control) valve consists of a line strainer, a non-return (check) valve, a pressure reducing valve, and an expansion relief valve. Supplied loose to be fitted to the incoming cold water mains pipework to reduce the maximum inlet pressure.
• 3 kW Incoloy (a better material than stainless steel) immersion heater, which is single-phase 240-volt powered, incorporating a control thermostat and resettable safety cut-out with WRAS independent approvals. For backup hot water heating or a cheap tariff electric power.
• We have the option to upgrade the immersion heater to a 6kW version on this indirect unvented cylinder, which can be powered by either 1 phase or a 3-phase electric power supply.
• The energy cutout thermostat is set to operate at 82°C (+/-5°C).
• A motorised valve is designed to cut the heat source plumbing to the cylinders in the event of a high-temperature cutout activation.

Warranty of our indirect unvented cylinder

Because this 210L indirect unvented hot water cylinder is manufactured in duplex high-quality stainless steel, which is highly corrosion resistant.

The hot water cylinder comes with a 25-year guarantee when used in a domestic water heating application (standard household use). Warranties vary if used in a commercial water heating application, then the warranty is reduced to 5 years.

G3 unvented indirect cylinder installation regulations

For England and Wales, our indirect unvented cylinder range is covered by Section G3 of the Building Regulations. For Scotland, it is covered by Technical Standard P3, and for Northern Ireland, it is covered by Building Regulation P5. Compliance can be achieved through a Competent Person Self-Certification Scheme, where a heating engineer with the Unvented G3 Certificate possesses the necessary knowledge and skills to install and maintain unvented hot water storage systems, or by notifying the local authority building control department.

Do not try to install or service an unvented cylinder unless you have the necessary certificate or qualifications. An unvented hot water cylinder can explode if not correctly fitted with all of the safety systems that they require.

Installation and maintenance considerations

Ensure the cylinder is installed by a qualified professional and follow the manufacturer installation requirements, with the tundish positioned for occupant visibility and away from electrical devices.

Regularly check and service the pressure relief valve in line with the manufacturer standards and servicing instructions.

To prevent hot water limescale buildup within the cylinder, especially in hard water areas, consider adding a scale defender.

 

Contact us

For more details, check stock availability, lead time, delivery, price or to purchase our 210 litre indirect unvented cylinder, as we sell direct our competitively priced cylinder, which is made in the United Kingdom from duplex stainless steel with quality manufacturing methods and a manufacturer 25 year warranty (for domestic use). Please contact our sales team on 01202 822221 or use our site email contact form.