
High recovery cylinder range – 200 to 2,000 Litres

High revcovery or high gain cylinders from 200 to 2,000 Litres – unvented cylinders or vented options from Flexiheat UK
A high recovery cylinder is an increasingly popular model in domestic hot water heating systems. These advanced hot water production and storage solutions are revolutionising how users meet their hot water demands, offering many advantages: maximum heat transfer, high efficiency, reliability, and cost-effectiveness compared to standard-size coil cylinders.
This type of hot water cylinder can also be referred to as a high gain cylinder, rapid recovery hot water cylinder, or quick recovery hot water cylinder.
A high gain cylinder allows heating engineers to install smaller cylinders as a space-saving option without losing water heating performance.
You can purchase this product range as vented cylinders or as unvented cylinders, with an expansion vessel kit accommodating the water expansion.
Understanding a quick recovery hot water cylinder
A high or rapid recovery cylinder is a type of hot water storage tank designed to heat water quickly and efficiently. They are an indirect hot water storage cylinder, which can be powered by a boiler (gas boiler, electric boiler or oil boiler) or by a high temperature heat pump.They are available as an indirect fast recovery unvented cylinder or as an indirect vented hot water cylinder, so we the full range to cover every installation requirement.
Maximum heat transfer
The heat exchanger coil of our quick recovery single coil cylinder range are the largest on the UK market. We blow away our competition on this, as this feature ensures that far more domestic water is in contact with the surface area of the heating coil exchanger, dramatically enhancing the transmission of heat between the primary and secondary water and thus the high recovery rate of the cylinder.
Unlike traditional cylinders that may take hours to heat a full tank of water, quick recovery cylinders can replenish hot water supplies rapidly, making them ideal for locations or applications with high-demand periods.
The “recovery” in high recovery refers to the speed at which the cylinder can heat cold water to the desired temperature after hot water has been drawn from the system. This rapid recovery is achieved through a large coil heat exchanger and improved insulation.
Key Benefits of High Recovery Cylinders
- Rapid Hot Water Replenishment: The primary advantage of high recovery cylinders is their ability to quickly heat water. This ensures a consistent supply of hot water, even during peak demand periods.
- Energy Efficiency: These cylinders, despite their high-performance capabilities, feature an energy-efficient design. They incorporate features like enhanced insulation to minimise heat loss and maximise energy consumption.
- Space Savings: High recovery cylinders can often provide the same hot water output as a larger traditional cylinder while occupying less space. This makes them especially valuable in commercial settings where space is limited.
- Cost-Effectiveness: Economical, as less stored hot water is required, and the long-term operational costs are often lower due to improved energy efficiency and reduced maintenance needs.
- Because a lot of hot water is not heated and squandered when it is not needed. Additionally, these fast recovery hot water cylinders significantly decrease boiler cycling, which results in significant fuel bill savings and increased client satisfaction.
- Versatility: These systems can be tailored to meet specific commercial needs, with options for different fuel types (gas or oil boilers, electric, or hybrid systems) and various capacities.
- Reliability: Built for heavy use, our quick recovery hot water cylinders are designed to withstand constant use, reducing downtime and maintenance requirements.
- Improved Hygiene: Our high recovery hot water cylinder range includes features to prevent the growth of bacteria, ensuring a safer hot water supply.
- Immersion heater top-up or backup—various immersion heater kW outputs can be fitted to either operate as a top-up or backup water heater should you lose the primary heating source during the installation.
- With options of the standard glass lined or corrosion resistant stainless steel domestic hot water storage tanks.
Heat pumps
Our large coil indirect hot water cylinders, or rapid recovery hot water cylinders, are also good for heat pump systems, which need a large coil and an electrical immersion heater to raise the stored water temperature to 60°C to kill Legionella. This is because heat pump systems normally have lower flow temperature performance of around 55°C.
Rapid recovery hot water cylinder heating performance data
The high gain cylinder, or quick recovery cylinder, water heating performance is directly related to three factors.
- The water temperature feeding the coil heat exchanger in the hot water tank.
- The volume of this heating water that flows to the coil of the indirect water heater.
- The water temperature rise – i.e., from 10°C cold water to 60°C.
Domestic hot water heating performance from 10°C to 60°C
Recovery rates, kW outputs and flow rates detail for our high gain indirect cylinders.
Domestic hot water heating performance from 10°C to 45°C
Recovery rates, kW outputs and flow rates detail for our high gain indirect cylinders.
Download the brochure for the 200 to 500 Litre low pressure drop coil high gain cylinders, showing weight, dimensions in mm, outlets, etc., this range has no inspection / clean out port here
ELC “HF” 200,300 and 500 litre quick recovery cylinders with low pressure drop coil brochure
Download the brochure for the standard 200 to 2,000 litre high recovery hot water cylinder models, showing weight, dimensions in mm, outlets etc – these units have an inspection / clean out port as standard here
ELC 200 to 2,000 litre quick recovery cylinders with extra large coil and inspection flange brochure
Vented or Unvented high gain cylinders
We can provide the models in a vented or unvented water heating configuration – we just add an expansion vessel kit, pressure and temperature safety valve, etc., for unvented water heater requirements.
Commercial water heating users
The primary users of high recovery cylinders are commercial entities with high hot water demands, such as:
- Hotels, restaurants, and caravan or camping shower room blocks.
- Hospitals and healthcare facilities
- Industrial kitchens and food processing plants
- Launderettes and commercial laundry facilities
- Sports centres and gyms
These businesses benefit from the consistent hot water supply and energy efficiency that quick recovery hot water cylinders offer.
Insualtion of our quick recovery hot water cylinders
All models have low heat loss insulation fitted as standard,which complies with the ErP regualtions with low global warming potential and ozone depletion potential.
Hard water
A lot of the United Kingdom has hard water conditions (please see the below map). You should fit a suitable scale inhibitor system or water softener to be positioned on the pipe connections before the indirect fast recovery hot water cylinder to maintain suitable water quality and prevent limescale on the coil and the immersion heater of the calorifiers.
Water hardness levels vary across the country, but approximately 60% of the United Kingdom is within hard water areas.
A 1 mm layer of limescale can reduce heating efficiency by about 7%, and a 1.6 mm layer can reduce it by 12%.

Water hardness map of the UK and Ireland – a lot of the country is Hard to Very hard in terms of calcium levels, which effects scale potential.
Contact us for your quick recovery hot water cylinder requirements
For more details, check stock, lead time, delivery, price, or to order our reliable and high quality high recovery cylinders, as we sell our high performance and competitively priced high gain cylinders directly. Please call our sales service team at 01202 822221 or use our site email contact form.