Calorifier Ancillary Equipment


World Heat Cylinders provides a comprehensive selection of ancillary equipment specifically designed to complement and subsequently enhance the performance, safety, and longevity of your commercial calorifier systems. Indeed, from complete unvented system kits to specialised components like inspection openings and de-stratification pump sets, we ensure every part meets our exacting quality standards for reliable operation. Therefore, whether you are specifying a new installation or upgrading an existing system, explore our range of essential calorifier ancillaries below.


Unvented System Components & Kits


For safe and compliant operation of unvented commercial calorifiers, World Heat Cylinders offers comprehensive unvented system kits and individual components. Specifically, these kits are meticulously specified to integrate seamlessly with our large commercial calorifier range, thereby ensuring optimal performance and adherence to UK regulations, including G3 Building Regulations.

Our standard unvented kits typically include:

  • Inlet Control Group: Comprising a pressure reducing valve (PRV), strainer, check valve, and balance cold water take-off. PRVs are available for various pressure requirements and connection sizes up to 6″.
  • Expansion Vessel: To accommodate the expansion of heated water. We supply expansion vessels correctly sized for systems up to 3,000 litres and beyond, crucial for preventing overpressure.
  • Temperature & Pressure Relief Valve (T&P Valve): An essential safety device to release excess temperature or pressure.
  • Tundish: To provide a visible discharge point from safety valves.

Consequently, by choosing WH Cylinders’ unvented component kits, you benefit from:

  • Guaranteed Compatibility: Components are selected to work flawlessly with your chosen calorifier.
  • Regulatory Compliance: In addition, all parts meet relevant UK standards for safety and performance.
  • Simplified Specification: Furthermore, you save time by specifying a complete, proven kit.
  • Quality Assurance: Crucially, we provide durable, high-quality components for long-lasting reliability.

Moreover, we can also supply individual unvented components to suit your specific project requirements. Therefore, contact our technical team to discuss your calorifier system design.


Unvented system components including expansion vessel, pressure reducing valve, and safety valves for commercial calorifiers.

Unvented system components kit for World Heat commercial calorifiers, including expansion vessel and valves.


Calorifier Inspection Openings & Manways


To facilitate essential routine maintenance, cleaning, and inspection, World Heat Cylinders offers robust inspection openings for our calorifier ranges. Indeed, these access points are crucial for prolonging the life of the calorifier, ensuring optimal performance, and also assisting with compliance for Legionella control (as per ACoP L8 guidelines).

Our inspection openings typically feature:

  • Durable Construction: Manufactured from materials compatible with the calorifier shell for longevity.
  • Secure Sealing: High-quality gaskets and bolted flanges (for manways) to ensure a watertight seal.
  • Variety of Sizes: Standard inspection manways and handholes are available with common diameters such as 250mm, 350mm, and 450mm, suitable for various calorifier capacities and access requirements. Bespoke sizes can also be accommodated.

Specifically, benefits of incorporating appropriately sized inspection openings include:

  • Simplified Maintenance: Easier access for cleaning scale build-up and sediment.
  • Thorough Inspections: Furthermore, this allows for visual inspection of internal surfaces and components like coils.
  • Enhanced Safety: Importantly, it supports water quality management and Legionella risk assessment.

Therefore, specify inspection openings on your WH Cylinder calorifier to ensure ease of service throughout its operational life.


Commercial calorifier with a large bolted inspection manway for maintenance access.

Commercial calorifier with large inspection manway for maintenance, by World Heat Cylinders.


Calorifier De-Stratification Pump Sets


Thermal stratification within a calorifier – where layers of water at different temperatures form – can, for instance, lead to reduced energy efficiency and subsequently create potential breeding grounds for Legionella bacteria in cooler, stagnant zones. However, World Heat Cylinders offers pre-plumbed de-stratification pump sets designed to counteract this issue effectively.

Essentially, our de-stratification pump sets work by:

  • Actively Circulating Water: The pump gently circulates water within the calorifier, mixing the layers to achieve a more uniform temperature throughout the stored volume.
  • Eliminating Cold Spots: As a result, this circulation prevents the formation of cold spots at the base of the cylinder, which can be a prime area for bacterial growth.
  • Improving Energy Efficiency: Furthermore, by maintaining a consistent temperature, the primary heat source can operate more efficiently, and hot water delivery is more predictable.

Key benefits of installing a WH Cylinders de-stratification pump set include, for example:

  • Enhanced Legionella Control: A critical component in managing Legionella risk, thus contributing to ACoP L8 compliance.
  • Increased System Efficiency: Additionally, it reduces energy waste associated with stratified water.
  • Improved Hot Water Availability: Moreover, this ensures more of the stored water is at the desired temperature.
  • Pre-Plumbed Convenience: Finally, it is supplied as a ready-to-install unit for ease of fitting and reduced site time.

In conclusion, our de-stratification pump sets are suitable for a wide range of commercial calorifiers. Therefore, discuss your system requirements with our team to ensure the correct specification for your application.


Pre-plumbed de-stratification pump set for commercial calorifiers to ensure even temperature and Legionella control.

Pre-plumbed de-stratification pump set on a WH Cylinders calorifier for improved temperature control


Discuss Your Calorifier Ancillary Needs


Our experienced technical sales team is ready to assist you in selecting the correct ancillary equipment for your commercial calorifier project. Whether you require a complete unvented kit, specific safety components, or advice on system optimisation, we can provide expert guidance and competitive quotations.

Contact us today on 0161 343 8610, email sales@whcylinders.co.uk, or request a callback via our contact page to discuss your requirements.