System Boilers

System boilers

Unlike combi boilers, system boilers are not connected to the cold mains. A coil in the cylinder carries the central heating water at high temperature through the cylinder, heating its contents.

System boilers are a popular choice for larger households in the UK due to their compact yet powerful nature, economical running costs, and efficient delivery of heating and hot water.

Unlike conventional boilers, a system boiler doesn’t require a cold water storage tank, so it needs considerably less space to be installed. They do, however, require a hot water cylinder. The hot water cylinder means that you’ll have access to a constant stream of hot water, even when multiple people are using it. This comes as music to the ears of those who live in a household with multiple bathrooms and don’t enjoy their showers being cut short due to lack of supply.

System boilers hold several similarities with regular boilers, but also, some very important differences. Regular boilers, also known as conventional or heat-only boilers, store hot water for later use much like system boilers. They are also found in older, larger homes. However, regular boilers are kept artificially under pressure with the use of a header tank in the loft (also called a feed & expansion tank), whereas system boilers use a pressurised heating circuit, topped up by mains water. Expansion vessel is often internal in a system boiler.

Ideal Logic Max System Overview

The Ideal Logic Max System Boiler Combines the Same Great Features as Ideal’s Award-winning Logic+ System with the Addition of a High Quality Ideal System Filter. Designed With Quality in Mind, The Logic Max System Keeps the Component Count Low to Maximise Reliability, These Include the Latest Generation Honeywell Gas Valve. The compact boiler Can be Installed in a Kitchen Cupboard. The Ideal Logic Max System Comes with A 10 Year Warranty and Features Service Indication, ProSystem Function, Built In Frost Protection And Compatibility With A Range Of Additional Controls.

  • Ideal System Filter
  • Compact Cupboard Fit
  • Large Back-lit Display & Easy to See Pressure Gauge
  • Fully Modulating Operation to Low Outputs
  • Easy To Install and Service
  • Compatible With Ideal Touch Heat & System RF and any additional controls
  • Built In Frost Protection
  • 10 years Parts & Labour warranty (when serviced annually)
  • Dimensions in mm: H 700 x W 395 x D 278

Vaillant ecoFIT pure System Overview

The Vaillant ecoFIT pure system boiler is part of Vaillant’s exciting and dynamic range of system boilers, ideal for all size properties. The compact size and optional rear flue fitting mean’s this boiler is ideal for even the snuggest of installations including kitchen cupboards and small cloakroom spaces. Quite Mark-approved, the ecoFIT pure system is ultra-quiet making it perfect for installations in social spaces and high-traffic areas of a home. Combining the best of German engineering and British manufacturing, the ecoFIT pure system boiler is resilient and built for a long-life. The clear LED display, coupled with the easy to recognise Vaillant fault codes create a simple to use system where the heating can be controlled to the desired temperature, ensuring maximum efficiency within the heating system. The fault codes also provide quick and accurate information necessary for servicing and diagnosing what is wrong with the system.


  • Five system models covering 12, 15, 18, 25 or 30kW heating outputs
  • Easy installation and maintenance
  • Compact, cupboard fit solution
  • Premium quality components
  • Compatible with Vaillant’s intelligent range of controls and additional external controls
  • Awarded Quiet Mark accreditation – one of the quietest boilers on the market, designed for a peaceful home (excludes 15kW and 30kW models)
  • 10 years Warranty (when serviced annually)
  • Patented 4-sided cooling and water agitation of the heat exchanger reduces stress on the heat exchanger for longer life reliability and reduced maintenance costs
  • Dimensions in mm: H 700 x W 390 x D 295

Worcester Greenstar i System Overview

The Worcester i System Boiler is the perfect choice for all type and size properties. Offering compact dimensions, a low lift weight and A-Rated efficiency, the isystem has the potential to save money on annual heating bills and offer reliability through even the coldest months. The iSystem Boiler will require a hot water cylinder in order to deliver hot water to the property. The high efficiency of the iSystem boiler can cut heating and hot water bills by 15-20% annually (When replacing an older, G-Rated boiler) and is up to 30% cheaper to run. These savings mean that over the years the boiler will essentially pay for itself, as the quality of Worcester boilers means that you won’t need to replace it for many years. Easy to use, the Worcester iSystem boiler includes simple boiler controls to ensure your boiler is set at the correct temperature, while also providing operational information and diagnostics to help with maintenance.

  • SEDBUK A-Rated efficiency
  • Compact and lightweight
  • Simple boiler control knobs with clear temperature display
  • On-board operational information and diagnostics
  • Fits in a standard kitchen cupboard
  • Low energy pump reduces electrical usage
  • CondenseSure style syphon inside
  • 10 year guarantee (when serviced annually)
  • Dimensions in mm: H 690 x W 390 x D 280