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World Heat Cylinders · 0161 343 8610 · sales@whcylinders.co.uk
Domestic · Unvented cylinder
Ultra Slim Unvented Hot Water Cylinders (400mm)
Our narrowest unvented cylinders — 400 mm diameter — for apartments, compact utility rooms and tight cupboards.
- 400 mm diameter
- 60–120 L standard sizes
- Direct and indirect models
- Duplex stainless steel vessel
- ErP class C
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What’s included Specifications Datasheets & downloads
Made in Manchester- ISO 9001
- WRAS
- G3
What’s included
Supplied with every cylinder
Every SuperFlow cylinder comes with a full unvented kit, so you have everything you need for a G3-compliant installation.
- Expansion vesselTakes up the water’s expansion as it heats
- Inlet manifold blockPressure reducing valve, pressure relief valve, strainer and check valve in one block
- Temperature and pressure relief (T&P) valve
- TundishThe visible air gap on the discharge pipe
- Dual mechanical thermostatControl and high-limit thermostat for the boiler coil (indirect models)
- Two-port zone valveControls the boiler’s flow to the coil (indirect models); we confirm it on your quotation
Exact kit contents can vary with the cylinder size; we confirm them on your quotation.
About our unvented kits and spare partsTechnical data
Specifications
SuperFlow Indirect Ultra Slim — 400 mm diameter
| Capacity (litres) | 60 | 90 | 120 |
|---|---|---|---|
| Height (mm) | 1000 | 1400 | 1860 |
| Diameter (mm) | 400 | 400 | 400 |
| ErP class | C | C | C |
SuperFlow Direct Ultra Slim — 400 mm diameter
| Capacity (litres) | 60 | 90 | 120 |
|---|---|---|---|
| Height (mm) | 1000 | 1400 | 1860 |
| Diameter (mm) | 400 | 400 | 400 |
| ErP class | C | C | C |
Figures are from our current product data. Connection positions are confirmed on the drawing for each order. Other sizes and configurations are built to order.
Must be installed by a qualified unvented (G3) installer and registered with building control.
Documents
Datasheets & downloads
Datasheets
Installation & service manuals
ErP labels & data
Certificates
Brochures
Can’t find a document? Search the downloads library, browse all product datasheets and manuals, or email sales@whcylinders.co.uk.
In detail
About Ultra Slim Unvented Cylinder
At World Heat Cylinders, we understand that modern building designs and retrofit projects often present significant space constraints. That's why "size matters," and our specialised Ultra Slim Unvented Cylinders are engineered to provide a high-performance hot water solution where installation space is at an absolute premium. With an exceptionally narrow profile, typically 400mm overall diameter, these stainless steel unvented cylinders are perfect for tight cupboards, compact utility rooms, apartments, and other challenging locations in both new-build and refurbishment applications.
Our Ultra Slim range delivers all the benefits of mains pressure hot water – powerful showers and fast-filling baths – without compromising on quality or efficiency, even in the most restricted spaces. We offer both plain and pre-plumbed options within this range.
Advantages of Our 400mm Ultra Slim Design
Choosing a World Heat Cylinders Ultra Slim Unvented Cylinder offers several distinct advantages:
- Space-Saving Design: With a minimal 400mm diameter, these cylinders fit where others simply cannot, unlocking valuable space.
- Mains Pressure Performance: Enjoy high flow rates and balanced hot and cold water supplies throughout the property.
- Versatile Application: Ideal for apartments, city dwellings, modular builds, and any installation with restricted access or limited plant room area.
- Direct and Indirect Options: Available for all-electric heating (Direct, typically with dual immersion heaters for faster reheat) or for connection to a conventional boiler (Indirect, with a high-efficiency internal coil).
- Stainless Steel Durability: Manufactured from high-quality Duplex stainless steel for excellent corrosion resistance and longevity.
- High Efficiency Insulation: Featuring foam injected, zero ozone depletion potential (ODP) insulation to minimise heat loss and reduce energy consumption.
- Pre-Plumbed Availability: Options for factory-fitted pipework and components can further reduce on-site installation time in confined spaces.
Bespoke Options for Ultra Slim Cylinders
While our standard Ultra Slim Unvented Cylinders cater to many common requirements for 400mm diameter units, we recognise that unique projects may demand further customisation. As specialist cylinder manufacturers, World Heat Cylinders can offer bespoke modifications. This includes specific tapping sizes and positions, tailored immersion heater configurations, or unique bracketry for challenging installations.
If you have a requirement for an ultra slim cylinder with non-standard features, please contact a member of our technical sales support team for further information and to discuss your project. You can reach them on 0161 343 8610 or via email at sales@whcylinders.co.uk.
Help choosing and specifying
Guides and tools
- Will it fit? Cylinder space checkerEvery cylinder that fits your cupboard or plant space
- Replace an existing cylinderThe World Heat equivalent of the cylinder there now
- Find a cylinderThree questions: heat source, size and the space you have
- Replacements for discontinued cylindersWhere a model you used to fit has gone out of production
Explore the range
Related products
Need this tailored to your project or system?
Different connections, coil, size, controls or finish: our design team builds to your requirements.
We also build own-brand ranges for OEM partners.
Need a cylinder built to your specification?
From 10 litres to 10,000 litres, our Manchester team designs, manufactures and tests every vessel in-house. We confirm and respond to every bespoke enquiry within 48 hours, and standard range enquiries immediately. If you need a price on a standard product, don’t hesitate to call and speak to one of our team on 0161 343 8610.We confirm and respond to every bespoke enquiry within 48 hours, and standard range enquiries immediately. If you need a price on a standard product, don’t hesitate to call and speak to one of our team on 0161 343 8610.We confirm and respond to every bespoke enquiry within 48 hours, and standard range enquiries immediately. If you need a price on a standard product, don’t hesitate to call and speak to one of our team on 0161 343 8610.