What is a primary cause of an external leak in a heat exchanger?

An external leak in a heat exchanger can often be attributed to cap seal failure. Cap seals are critical components that help maintain the integrity of the heat exchanger by sealing connections where fluids enter or exit. Over time, these seals can degrade due to various factors, such as temperature fluctuations, chemical exposure, or mechanical wear. When a cap seal fails, it creates a pathway for the fluid to escape the system, leading to leaks.

In contrast, while corrosion of the pipe, incomplete connections, and excessive pressure can indeed contribute to leaks, they are not the primary cause of external leaks in a heat exchanger. Corroded pipes may lead to leaks, but it typically occurs over a prolonged period. Incomplete connections can be prevented during installation. Excessive pressure may lead to leaks in some scenarios, but it often causes internal failures or ruptures rather than external leaks. Therefore, failure of cap seals directly relates to immediate and observable leaks in a heat exchanger system.