Pumps play a critical role inside our mechanical rooms, providing boiler feed water, chilled water circulation, fuel oil supply, fire suppression, condensate return, and much more. Facilities are filled with all types of pumps that keep these systems online. With these pumps being such a critical factor for facilities, it’s important to keep regular checks on these components and incorporate each one into a scheduled maintenance plan.
Within a boiler room, one of the biggest reasons for pump failure is cavitation. Cavitation is a phenomenon that occurs when the water at the suction end of a feed pump turns to vapor. As this water passes through the impeller, rapidly forming bubbles begin to rupture and cause a shock-like effect inside the pump’s casing. The consequences of cavitation are reduced efficiency and eventual failure. While cavitation is not something that is directly mitigated through maintenance, proper temperature, and pressure monitoring can identify a pump that could be headed for trouble. Cavitating pumps will often have a sound like sand, rocks, or marbles being flung around inside the pump casing.
Boiler feed pumps have to handle hot condensate while overcoming the boilers operating pressure. These pumps are selected based on a performance curve and should only be replaced with pumps also meeting those performances requirements. Pumps that operate too far left or right on their performance curves are headed for failure. Each pump set should have properly functioning gauges on the suction and discharge sides of the pump. Ensure that the NPSHa and NPSHr of installed feed pumps are sufficient to reduce the risk of pump cavitation.
For the most part, pumps require very little maintenance. One of the first steps in developing a maintenance plan is to identify all critical system pumps installed. Utilizing the manufacturers’ data, look for specific maintenance procedures and frequencies recommended for your equipment. Lubricate bearings in accordance with manufacturers’ recommendations, and monitor for increased bearing temperature or excessive vibration. Misalignment and vibration lead to pump problems rapidly. Large facilities with numerous pumps will often have installed sensors at each pump to remote monitor and annunciate major changes in vibration.
A Pump repair technician removes the casing to replace bearing and impeller.
Mechanical rooms rely on pumps for many different processes within facilities.
Cavitation erodes impellers, drastically decreases pump efficiency and ultimately leads to pump failure.
On the note of vibration, an increase in vibration is typically the tell-tale sign that something has changed. This should become part of daily monitoring so as to know exactly when changes occur. Alignment of the shaft seal can often be the culprit of this increase in vibration. Couplings should be inspected at frequencies consistent with operational needs, but at a minimum, annually. Look for worn or broken parts, as well as couplings that look like they are at their end of service. Planned coupling replacement is a lot less expensive than an offline pump due to coupling failure.
It’s also important to keep an eye out for leaks occurring. Generally speaking, the only place a pump should be wet, is inside its casing. Leaks are usually a good sign that a shaft seal is on its way out. Plan to inspect these seals at set frequencies and monitor for insufficient packing or seals.
Regular monitoring is key to preventing pump failure. Monitoring the gauges, lubrication, vibration, and leaks will identify exactly when a problem occurs and can often be remedied much faster than a pump repair or replacement.
If your facility needs repair, replacement, or refurbishment of any of your installed mechanical systems pumps, contact Power Mechanical, Inc. We have a dedicated pump repair and valve shop that’s the best in its class to get these systems back online quickly and cost-effectively. 1-877-764-7832