Pristine Performance: Keeping Commercial Heating Systems Clean

While keeping any heating system clean is key to its performance and extending its operational life, commercial heating systems are under even more pressure to ensure premises run smoothly. Andy Green, Technical Director at Potterton Commercial outlines the importance of system cleanliness in commercial installations.

If a domestic heating system isn’t maintained and serviced correctly you can be left with an uncomfortable and expensive problem on your hands. But, with a commercial system, the consequences can go far beyond this. With a number of people and processes reliant on heating and hot water, if these systems aren’t maintained correctly, then commercial premises are at risk of system downtime which could mean they have to close, losing out on business. Even if the system doesn’t shut down completely, failing to keep it clean and performing as smoothly as possible will result in increased energy costs from excessive fuel usage along with potential financial penalties due to increased carbon emissions.

As such, there are some important actions which can be taken in the interest of keeping these commercial systems functioning as they should.

Installation Inspections

There are some key operations which can be performed by a qualified service engineer before a commercial heating system is even installed. This will ensure system cleanliness from the outset for correct operation and to retain any warranty. For example, if the boiler is connected to existing flue ducts, these should be thoroughly cleaned as residual products of combustion may detach from the walls during operation and obstruct the flow of fumes.

In a Domestic Hot Water (DHW) circuit, if the water is harder than 20°F (1°F = 10mg calcium carbonate per litre of water), a polyphosphate dispenser or an equivalent treatment system which is compliant with current regulations should be installed. Other considerations include thoroughly flushing the system after installation of the appliance and before use, and making sure the materials used for the DHW circuit comply with Directive 98/83/EC.

For a heating circuit in a new system, before the boiler is installed, the system must be cleaned and flushed to eliminate residual thread-cutting swarf, solder and any solvents. This can be done using suitable off-the-shelf non-acid and non-alkaline products that do not damage metal, plastic and rubber parts. To protect the system from scale, inhibitors specifically designed for heating circuits should be used in strict compliance with the manufacturers’ instructions.

For an existing system, there are some extra precautions to take as the presence of foreign bodies in the heating system can adversely affect boiler operation by causing overheating and excessive noise in the heat exchanger. Therefore, before installing the boiler, the system should be drained and cleaned to remove sludge and contaminants, using suitable proprietary products for heating circuits.

Annual Assessments

Performing a series of routine checks on an annual basis is key to optimising boiler efficiency, and many of these checks involve keeping the system as clean as it can be. For example, a vacuum cleaner can be used to check for any impurities inside the combustion chamber. What’s more, it’s important to check that the flue and air ducts are unobstructed and that there are no blockages inside the siphon.

Clean the Condensate Trap

In particular, it’s important to clean the heating system’s condensate trap as part of the annual service. With mostnew boiler installations and boiler replacements being of a condensing type since 2005, these systems create a significant amount of condensate which is collected by a condensate trap. Thankfully, cleaning this part of the boiler is a simple task but shouldn’t be neglected given its impact on the overall performance of a heating system and the need to dispose of this liquid correctly.

The lower section of the water condense trap will need to be unscrewed and cleaned by flushing it out with water. The same section should then be filled with water until about 10mm below the upper edge. Once complete, it should be fastened onto the condense trap again.

Heat Exchanger Housekeeping

The heat exchanger plays a crucial role in ensuring the efficient transfer of heat in a heating system. Available in stainless steel, aluminium alloy and cast iron, their material will determine how well they transfer heat, their corrosion resistance and therefore how often they need to be cleaned.

The cleaning process usually involves sucking up the residue inside the combustion chamber and removing any scale using a brush with plastic bristles. Any surfaces which need to be cleaned should be sprinkled generously with an appropriate liquid cleaner and left for 10 minutes before brushing the surface, with this process repeated if required to remove excess dirt. When cleaning is finished, the surface should be rinsed with water and the gasket of the burner support flange, replaced.


Some commercial boilers, such as the wall-hung Sirius Three range, have the option of a hydraulic system manager as an additional accessory for the system to make maintaining system cleanliness easier. This essentially acts as a low loss header, dirt separator, magnetic filter, air separator and flow velocity manager – to ensure clean system water and removing air, dirt and metal to prevent noise. Despite this, it’s essential to include chemical water treatment as part of the installation and ongoing maintenance schedule.

Ultimately, taking a proactive approach to keeping a commercial heating system as free from contaminants as possible is key to ensuring it operates safely and efficiently while reducing the chances of a breakdown.

For more information on Potterton Commercial’s Sirius three range of ErP compliant wall-hung and floor standing boilers, please visit