Choosing The Right Boiler Heat Exchanger

Updating a heating system with refurbished or new commercial boilers provides long-term economy and improved efficiency. Achieving a maximum return on investment is dependant on choosing the correct type of boiler heat exchanger to suit its location.

commercial boiler

What is a heat exchanger in a boiler?

A boiler heat exchanger is what lets you exchange the heat between two substances without letting them mix together. The heat exchanger holds a long, coiled pipe that is surrounded by liquid. Hot liquid gets pumped through the coil which gradually heats the water surrounding it. A heat exchanger doesn’t allow these two substances to mix, as this would act too slowly – the hot liquid could only marginally increase the water’s temperature if they were mixed together.

A new building offers greater flexibility and control over the design of the piped network. The type of building, quality of the water and the cost are important considerations but selecting an ideal metal is crucial.

At ST Heating Services, we provide guidance to help you make the right choice when it comes to installing a boiler heat exchanger for your commercial boilers. Boiler heat exchangers are designed with one main task in mind: transfer of thermal energy from the hot water side to the cold water side. This is done by transferring some of that hot water’s energy into the cold water which then becomes heated and ready for use.

Boiler manufacturers recommend their own proprietary equipment, but it may be worth considering an alternative brand if there are significant price differences between brands or where there is no difference in performance across all brands.

There are different types of boiler heat exchangers including Shell and tube heat exchangers, double pipe heat exchangers, plate heat exchangers, condensers, evaporators and boilers.

Shell and tube heat exchangers are more common in domestic boilers due to the higher pressure they can withstand, whereas condensers, evaporators and boiler heat exchanger are used for industrial purposes.

Plate heat exchangers provide a better solution when there is high thermal demand with a small volume of water such as solar heating systems that require hot water on tap all day long.

In order to make an informed decision about which type of equipment is best suited for your project’s needs it pays to consider the following factors:

– The size requirements

– Flow rate requirements

– Pressure ratings (depending on system)

– Thermal efficiency (or energy transfer coefficient) required.

Aluminium Heat Exchangers

Aluminium heat exchangers offer a cost-effective, lightweight solution. Aluminium alloys include elements such as zinc and copper for increased strength and durability. The metal is a superb thermal conductor. It offers high resistance to corrosion from water particularly if the pH level is between 7 and 8.5. A clean water supply is necessary to ensure an uninterrupted flow through the typically narrow pipework.

Cast Iron

A traditional choice of metal with added silicon and carbon provides a robust, heavyweight construction. It’s particularly suited to refurbished systems due to its efficiency in managing accumulated debris within existing pipes. Cast iron retains heat effectively and has a high resistance to the corrosive effects of sulphurous gas. However, it is susceptible to deterioration when condensing is combined with flue gases that are acidic. It is occasionally necessary to install an additional heat exchanger to achieve optimum levels of energy efficiency.

Stainless Steel

Stainless steel alloys contain a minimum of 10% chromium producing a metal that combines medium weight with outstanding strength. The metal is a reliable conductor of heat and has a durability of up to ten years. It has a high resistance to corrosion and can tolerate a wide range of pH levels from 7 to 10. It’s an ideal choice for damp conditions such as swimming pool facilities.

Carbon Steel

Steel has a great strength and durability but it is vulnerable to corrosion which makes it less suited to condensing. However, this can be corrected by fitting a secondary heat exchanger. Carbon steel has high thermal conductivity making it a cost-effective choice. Heat exchangers with a steel shell are particularly suitable for pressure jet boilers with variable heat loads for fuel efficiency.

How do I know if my boiler heat exchanger is broken?

A faulty boiler heat exchanger may be due to a problem with the boiler or high sulphur content in your water.

The heat exchanger may leak if there is corrosion of the steel,

As well as this up to half of all boilers have an aluminium heat exchanger which has a long life expectancy. Alloys such as copper also offer good resistance to corrosion and wear, especially for use on higher-pressure systems where they are exposed to more thermal stress when operating at elevated temperatures. However, alloys can be expensive compared with stainless steel so it’s important that you choose wisely.

There might be some issues with metal fatigue making the heat exchanger prone for leaks and cracks depending on how much work it had done previously – sometimes even just one cycle could cause damage

If the burner flame flickers, is dull yellow or has any other unusual characteristics, then it could be an indication that you may have a broken heat exchanger and it may need repairing. The heat exchanger fault could be due to it being dirty or contain a crack.

Steel is not as thermally efficient for condensing boilers, so you may see some water droplets around the heat exchanger or at the exhaust stack. This means that there are too many cool surfaces and insufficient hot surface area to warm the gases sufficiently during operation.

Choosing ST Heating Services for the installation of commercial boilers in Manchester and the North West ensures experience and reliability for all aspects of maintenance and heat exchanger repairs. If you need advice on your boiler’s heat exchanger or your overall heating system, speak with our team at ST Heating. Our boiler experts are on hand to offer advice and guidance you may not even have considered, as well as provide top notch installation services to carry out any boiler maintenance, repair or installation services you need with minimal fuss. Contact us today if you need help locating or installing a high quality equipment solution for your commercial or industrial heating system! We’ll have what it takes so just speak to our experts at about any queries you may have regarding boilers in general, including their manufacturers, types and sizes.

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