PHAM NEWS | OCTOBER 2026 Gas & OilBoilers


Avoiding the cost of condensate discharge


As temperatures drop, installers will once again need to pay close attention to every aspect of a heating system to ensure reliable performance during the colder months. Andy Thompson from Wilo UK explains why condensate management matters and highlights the risks and costs that can arise when it is overlooked.


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roduced as a natural by-product of modern condensing boilers, mildly acidic condensate must be


removed safely and eff ectively to protect the boiler, condensate pipework and surrounding building fabric. When drainage arrangements are poorly designed or improperly installed, restricted fl ow and accumulated condensate can contribute to corrosion, leaks, premature component failure and costly callouts. Poor drainage can also aff ect


overall system reliability, and so installers should be particularly mindful of frozen or blocked discharge pipework as winter approaches. If condensate cannot discharge correctly, the boiler may lock out as a safety measure, or require intervention, causing disruption to heating and hot water supplies. This then increases the likelihood of avoidable service visits and emergency callouts during the busiest time of the year.


Why problems occur Most condensate-related faults can be traced back to insuffi cient drainage arrangements, unsuitable pipework design or inadequate discharge provisions. External pipework is


particularly vulnerable during winter. Long pipe runs exposed to low temperatures are more likely to freeze, preventing eff ective drainage. Similarly, blockages caused by dirt, debris or sludge can restrict fl ow and increase the risk of system shutdown. The pipework design also


plays a critical role. Condensate Modern solutions such as the


Wilo-NovaCON (pictured) are designed for compact installation and eff ective condensate removal. The condensate pump features integrated level monitoring, overfl ow protection, a non-return valve and a potential-free alarm contact. These provide monitoring and protective functions that can signal a fault or shut down compatible connected equipment before tank overfl ow, subject to correct installation and system compatibility.


Andy Thompson National sales manager for plumbing and heating at Wilo UK


By actively transferring condensate to a suitable drainage point, condensate pumps can help support reliable condensate discharge and reduce the risks associated with condensate build-up


pipes must be installed with an appropriate fall to allow gravity- assisted drainage. If the gradient is too shallow, liquid can remain trapped within the pipework, resulting in build-up and stagnation. Excessive pipe lengths and multiple bends can further restrict fl ow and create additional maintenance challenges. Wherever possible, condensate


should discharge to a suitable internal gravity drainage point; where external pipework is unavoidable, installers should follow the latest industry guidance and the boiler manufacturer’s instructions on sizing, insulation, sealing and termination. If gravity drainage is not


possible, the condensate pump becomes a vital part of the installation. An incorrectly specifi ed pump, poor positioning or pump failure can compromise drainage and expose the system to many of the same risks associated with poorly designed pipework.


The benefi t of pumps By actively transferring condensate to a suitable drainage point, condensate pumps can help support reliable condensate discharge and reduce risks associated with condensate build-up. For installers, condensate


pumps can off er greater fl exibility when designing heating systems. Because the discharge does not have to rely solely on a continuous gravity fall, a pump can enable the boiler to be positioned in a more suitable location within the property, even when a convenient nearby drain is unavailable. It can also reduce the need for


long external pipe runs, helping to minimise the risk of freezing while allowing condensate to be routed to the most appropriate discharge point. This can be particularly benefi cial where space, access or existing drainage arrangements would otherwise restrict the installation.


Minimising risks As temperatures fall and demand for heating increases, installers should prioritise eff ective condensate management at the design and installation stage. Although it may appear to


be a small part of the system, ineff ective drainage can have signifi cant consequences for reliability, continuity of service and maintenance costs. ◼ phamnews.co.uk/1026/40


CUT TO THE CHASE


 Condensate must be removed safely to protect the boiler and surrounding building fabric


 Installers should be mindful of frozen or blocked discharge pipework during winter


 Excessive pipe lengths and multiple bends can create additional challenges


 Condensate pumps can help to reduce the risks of condensate build-up and provide more boiler location options


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