The Joule Cyclone 90 Litre Unvented Indirect Cylinder is a compact stainless-steel hot water cylinder designed for indirect heating systems using a boiler, heat pump or solar thermal primary. With a 90-litre actual capacity, 316L stainless-steel coil and dense PU foam insulation, it provides reliable mains-pressure hot water while helping to minimise standby heat loss.
Built with an LDX 2101 stainless-steel cylinder, coated mild-steel outer casing and an 18 kW stainless-steel coil, this Cyclone indirect unvented cylinder is well suited to small domestic properties, apartments and space-restricted installations. Tested to BS EN 12897:2016 and supplied with a 1-year warranty, it offers a practical hot water storage solution for everyday domestic applications.
90 Litre Capacity
Indirect Unvented
18 kW Stainless Coil
LDX 2101 Stainless Steel
BS EN 12897:2016
Key Highlights
10 bar
Maximum Mains Pressure
Applications & Suitability
- Small residential homes, flats and apartments with modest hot-water demand.
- Under-bench cupboards, narrow plant rooms and utility spaces where installation space is limited.
- Indirect heating systems supplied by a boiler, heat pump or solar thermal primary.
- Renovation and retrofit projects requiring compact stainless-steel hot water storage.
- Domestic installations where low standby heat loss and corrosion-resistant construction are important.
Key Specifications
| Model |
— |
| Brand |
CYCLONE |
| Capacity |
90 L |
| Actual Capacity |
90 L |
| Product Group Code |
INDIRECT |
| Item Category Code |
Stainless |
| ERP Type |
IndirectUnvented |
| Cylinder Material |
LDX 2101 Stainless Steel |
| Outer Casing |
Coated Mild Steel |
| Thermal Insulation |
Dense PU Foam |
| Foam Thickness |
0 mm |
| Number of Immersions |
1 |
| Immersion Specification |
3 kW @ 230 V |
| Coil Material |
316L Stainless Steel |
| Number of Heat Exchangers |
1 |
| Coil 1 Rating |
18 kW |
| Coil 1 Surface Area |
0.52 m² |
| Coil 1 Maximum Primary Pressure |
3.5 bar |
| Coil 1 Resistance |
0.04 bar |
| Maximum Mains Water Pressure |
10 bar |
| Operating Pressure |
7 bar |
| Operating Temperature |
60 °C |
| Safety Valve Temperature |
90 °C |
| Unit Weight Empty |
39 kg |
| Unit Weight Full |
135 kg |
| Heat Loss |
1.06 kWh/24h |
| Tested To Standard |
BS EN 12897:2016 |
| Warranty |
1 Year |
Compact 90 Litre Hot Water Storage
With a 90-litre actual capacity, the Joule Cyclone is designed for domestic installations where a compact hot water cylinder is required. Its size makes it suitable for smaller homes, flats, apartments and space-restricted utility or plant-room installations.
The cylinder provides mains-pressure hot water storage as part of an indirect unvented system, making it a practical choice for domestic hot water applications with modest demand.
Indirect Heating with 316L Stainless-Steel Coil
The cylinder features a 316L stainless-steel coil with an 18 kW rating and 0.52 m² surface area. The indirect configuration is designed for connection to a primary heating system such as a boiler, heat pump or solar thermal loop.
- 316L stainless-steel coil construction
- 18 kW coil rating
- 0.52 m² coil surface area
- Maximum primary pressure of 3.5 bar
- Coil resistance of 0.04 bar
Stainless-Steel Cylinder Construction
The inner cylinder is manufactured from LDX 2101 stainless steel, providing a durable cylinder construction for everyday domestic hot water storage. A coated mild-steel outer casing provides the external finish and protection.
The cylinder is also fitted with dense PU foam insulation, with a stated heat loss of just 1.06 kWh/24h.
Auxiliary Immersion Heating
The Joule Cyclone 90 Litre cylinder provides one immersion provision with a specification of 3 kW @ 230 V. This provides an auxiliary electric heating option alongside the cylinder's indirect primary heating arrangement.
Pressure & Temperature Ratings
The cylinder has a maximum mains water pressure of 10 bar and an operating pressure of 7 bar. The stated operating temperature is 60 °C, with a safety valve temperature of 90 °C.
10 bar
Maximum mains pressure
7 bar
Operating pressure
90 °C
Safety valve temperature
Tested to BS EN 12897:2016
The Joule Cyclone 90 Litre Unvented Indirect Cylinder is tested to BS EN 12897:2016. The cylinder is supplied with a 1-year warranty, providing a defined warranty period for the product.
Ideal For
- Small homes with modest domestic hot water requirements.
- Flats and apartments requiring compact hot water storage.
- Utility cupboards and restricted plant-room installations.
- Indirect systems using boilers, heat pumps or solar thermal primary circuits.
- Retrofit and renovation projects where compact stainless-steel storage is required.
- Installations where low stated standby heat loss is a priority.
Frequently Asked Questions
What is the capacity of the Joule Cyclone cylinder?
The cylinder has a 90-litre actual capacity.
Is this an indirect unvented cylinder?
Yes. It is an indirect unvented cylinder designed for indirect heating systems.
What heating systems can the cylinder be used with?
It is suitable for indirect primary systems using a boiler, heat pump or solar thermal system.
What material is the cylinder made from?
The cylinder material is LDX 2101 stainless steel, with a coated mild-steel outer casing.
What type of coil does it use?
It uses a 316L stainless-steel coil rated at 18 kW, with a surface area of 0.52 m².
Does the cylinder have an immersion heater provision?
Yes. It has one immersion provision specified at 3 kW @ 230 V.
What is the maximum mains water pressure?
The maximum mains water pressure is 10 bar, with an operating pressure of 7 bar.
What is the warranty period?
The Joule Cyclone 90 Litre Unvented Indirect Cylinder comes with a 1-year warranty.
Joule Cyclone 90 Litre Unvented Indirect Cylinder
The Joule Cyclone 90 Litre Unvented Indirect Cylinder combines compact 90-litre hot water storage with an LDX 2101 stainless-steel cylinder, 316L stainless-steel 18 kW coil, dense PU foam insulation and auxiliary 3 kW immersion provision. With a 10 bar maximum mains pressure, 7 bar operating pressure, 1.06 kWh/24h heat loss and testing to BS EN 12897:2016, it is a practical solution for small domestic indirect unvented hot water systems.
