Water hammer is a troublesome but commonly-occurring issue that can plague a steam system. The most obvious symptom is the hammer-like noise it creates, but, when left unchecked, water hammer can cause serious damage to vents, traps, regulators, and piping. There are two types of water hammer. The most common type is usually due to an accumulation of condensate trapped in a portion of horizontal piping. Steam picks up the resulting water “slug” and hurls it into the nearest pipe fitting at high velocity. The second type is caused by a steam bubble forming or being pushed into a wet return line or pump discharge piping. When the bubble cools, it implodes with great force. Some common causes of water hammer are:
Near-boiler piping is not up to manufacturer specs
Bad steam quality (dirty water or high pH)
The boiler is overfired
Boiler line is priming or surging
Long nipple on Hartford Loop (s/b close nipple or wye fitting)
Close nipple or wye fitting is too close to boiler water line
Mains aren’t properly dripped
Clogged gravity-return line
Motorized valves (avoid on gravity-return systems)
Steam traps aren’t working
The causes of water hammer are often difficult to identify, so it is oftentimes tolerated, considered to be more of a nuisance than a problem. But when left unchecked, water hammer can result in costly repairs. An experienced steam professional like PJM Mechanical Contractors, Inc. can identify the causes of water hammer and resolve the issue.
PJM Mechanical Contractors, Inc. is a multi-faceted mechanical contractor providing construction and installation, service and maintenance, and design/build services in a comprehensive range of mechanical disciplines that include HVAC, plumbing, controls, refrigeration, custom metal fabrication, piping, fire protection, and backflow preventer testing. PJM primarily serves clients in pharmaceuticals, manufacturing, healthcare, institutional, and other various commercial and industrial sectors.