McDonald Commercial Cylinders

commercial cylinders

Commercial cylinders are designed for instances of continuous or high demand such as hotels, leisure centres, office blocks and restaurants, when there is a requirement for lots of hot water very quickly, without loss in performance. 

The McDonald Water Storage range of commercial cylinders are available in either copper, mild steel or stainless steel up to 100,000 litres with copper models available for urgent installations, within 10 working days. All cylinders are available with bespoke design flexibility, to suit your individual application. 

Buffer Tanks

Bespoke Buffer Vessels and Tanks Providing additional storage for secondary or primary water

Buffer Tank Accumulator Tanks

Buffer Tanks, or Accumulator Tanks as they are sometimes referred to, tend to be used in conjunction with renewable energy installations and in particular solid fuel and bio mass systems to provide a commercial cylinder solution.
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The PLATEflow plate heat exchanger is designed to supply hot water in situations where demand can vary over the course of a day.


PLATEflow heat exchanger system effectively decreases the amount of stored hot water required, while still delivering peak flow rates as demanded.
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Marine Calorifiers

Marine Calorifiers for hot water made from Copper and Customised to your specific design.

Marine Calorifiers

A marine calorifier is a specialised hot water storage vessel designed specifically to suit the demands of boats and yachts.
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  • Bespoke Calorifier tank solutions to suit Vented and Unvented Installations
  • Bespoke buffer vessels and tanks to provide additional storage capacity for secondary or primary water
  • PLATEflow technology available to supply hot water where demand varies through the day
  • Manufactured from either copper, mild steel or stainless steel to suit capacity, pressure and water usage
  • Units can be manufactured to suit renewable energy, such as Solar or Heat Pumps
  • Copper cylinders provide additional benefits including superior non-corrosive and anti-bacterial qualities to kill bacteria such as Legionella and Ecoli
  • All tanks and commercial water heaters manufactured to BS853
  • Copper calorifiers up to 3000 litres can be delivered in approximately 2 weeks from order
  • Galvanised cladded, white cased or spray foamed units available (dependant on model size)

When cylinders are specified for NHS installations, the Health Technical Memorandum 04-01, a Department of Health document outlines the requirements for Safe Water within Healthcare Premises. Part of this document outlines the specification of all hot water storage vessels used on NHS premises, with the primary requirement that they are to be manufactured from copper!

Our commercial water heater specialists can advise on the HTM04-01 requirements, in addition to the optimum design for the installation.

For more information click here.

Have you ever wondered what is involved in manufacturing a commercial copper cylinder?

Check out our time lapse video

Want to get a better idea of how a typical calorifier looks with the various components and connections?

Check out our 3D interactive model below:



The main materials used in commercial cylinder manufacture are

  • Copper with its flexible manufacturing properties
  • Stainless Steel used on larger systems and high working pressure
  • Mild Steel for primary storage vessels, not suitable for storing potable water

Commercial CylinderThere are three ranges of commercial cylinder available, with the material dependent on the water usage.

  • Copper cylinders are available up to 3000 litres and up to 3 bar, and suitable for use with either domestic hot water or primary heating water
  • Mild steel cylinders are manufactured up to 100,000 litres and up to 6 bar working pressure. These are only suitable for primary heating systems.
  • Stainless steel cylinders are available up to 100,000 litres and up to 10 bar, and suitable for use with either domestic hot water or primary heating water

It is essential to size the cylinder correctly, otherwise implications of over sizing could be:

  • Increased plant costs – both calorifier and ancillaries
  • Reduced ‘churn’ of DHW store – water quality
  • Increased energy consumption (standing losses)
  • Reduced efficiency
  • Increased utility requirements

PLATEflow system effectively decreases the amount of stored hot water required. They comprise of a plate heat exchanger, pre-piped and mounted on a buffer vessel to supply hot water in situations where demand can vary over the course of a day, but how do they work?

  • Plateflow schematicAt times of lower demand, all the hot water is generated instantly from the boiler via the plate heat exchanger (A), with any excess recharging the buffer vessel (B).
  • When demand exceeds the plate heat exchanger limit, water from the buffer vessel is also used (C).


Working Example

  • Peak demand 10 minutes @ 1 L/s = 600 litres
  • 100kW PHE provides 260 litres in 10 minutes
  • Shortfall made up from cylinder minimum 340 litres

Bespoke CalorifierOur technical team are able to assist and advise with the design and specification of any commercial cylinder.

The example shown in the image is a vented calorifier for a school in Manchester, which was part of an upgrade programme. The 650 litre calorifier measured 2000mm in height by 795mm in diameter.

It was designed to specific requirements including;

  • To work in conjunction with an 89kW boiler
  • Two back up immersion heaters
  • Insulation with galvanised case to be applied onsite due to restricted access space
  • Inspection manhole
  • Insulation and casing applied onsite

Commercial heat pump cylinderThe answer is yes, even standard heat pump temperatures can be utilised.

The example opposite show how a cylinder utilising heat pump input can pre-heat the mains cold water to 40 degrees before entering the second cylinder where the water is raised to 65 degrees before being delivered to the hot water outlets.

This type of configuration reduces the energy required by the immersions to reach the required 65 degrees, therefore reducing the running costs.

A range of insulation options are available to suit the application:

  • Removable galvanised casing, held with clasps, with rockwool insulation for onsite application
  • Injection foam insulation with white casing providing maximum heat retention (up to 700mm overall diameter)
  • Spray foam insulation for larger units

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