Leak Detection in Steam Boilers

What to Look For

• If you see water on the ground or on the outside of your boiler, this is usually a sure sign of leakage, but boiler leaks do not always show themselves in such an obvious way. Often, your boiler is so hot during operation that small leaks evaporate quickly. These leaks are still detectable, however. Look for rust, water stains, corrosion buildup, and deposits of mineral salts. Leaks deep inside your boiler might be invisible, but they can sometimes be detected by removing your boiler's external covers. If you don't know how to do this, a service technician can help you look for interior leaks.

Likely Locations

• Some of the most common leak points on steam boilers include tankless coil mounting plates, pipe fittings, around bolt openings, between sections of a cast-iron boiler, at the circulating pump mounting flanges and at the boiler temperature/pressure relief valve. Leaks can also occur around various other valves and drains. You might not know the location of all these parts, but you can find them by consulting your boiler's operation manual.

Hydrostatic Testing

• Boiler technicians use a process called hydrostatic testing -- often simply called hydro-testing -- to detect leaks. Hydro-testing involves filling the boiler system with treated water between 100 and 120 degrees Fahrenheit, gradually increasing the pressure at less than 50 pounds per square inch per minute and inspecting the entire system for leaks. Hydro-testing should only be performed by a certified professional, and can be included with your boiler's regularly scheduled maintenance to keep it running smoothly.

Warning

• If you find rusted and corroded parts while inspecting your boiler, it is generally a good policy to look but not touch. In many cases, rusted and corroded areas can already be so thin that poking at them can break right through, transforming a minor leak to a major problem. Mineral buildup can also be holding back a major leak, and chipping it away can only make matters worse. If you find leaks, contact a service technician who can repair or replace the parts if necessary.