Finding leaks in vacuum furnaces is a task that few people look forward to, however, it is important and necessary. Leaks happen almost always and can occur suddenly or develop over time. They can damage both the material being heat treated as well as internal furnace components. When left unchecked leaks will stop the furnace from pumping down and will compromise the heating elements. Small leaks often go undetected since the pumping system can overcome them, but they can still cause continuous and eventually catastrophic damage. It is therefore highly recommended that routine leak checking and repair be a part of any good preventative furnace maintenance program.
“Why is avoiding leaks important? If a vacuum system is not “tight” or rather, tight enough, then not only is effort wasted trying to create and maintain ideal conditions (as an open system could never maintain the ideal vacuum anyway), operators and products are needlessly put at risk. For example, toxic gases/fluids could leak out of the vacuum; vacuum processes deliver faulty products due to impurities entering through the leak; air could enter the system and potentially contribute to the formation of an explosive mixture; the vacuum system could be damaged; and the surrounding environment could be affected.”
Source: Vacuum Science World