Let it flow: How to use pumps for boiler and chiller flushes

It takes a complete HVAC system to maintain climate control in any largescale commercial or industrial facility. When one part starts to fail, it can create a chain reaction within a system. Occasionally, debris and buildup can clog a chiller line, jeopardize system operations, and create uncomfortable temperatures for tenants and guests alike.

At Sunbelt Rentals, we’re here to assist mechanical contractors with a full catalog of state-of-the-art equipment and the technical knowledge to help you work smarter, not harder. Here’s an introduction to how our pumps can help you flush chiller lines for a more complete cool.

It's all about distribution

Boilers and chillers operate on the same principle. Both utilize a permanently installed pump to distribute hot and cold water back and forth to the HVAC system’s coils, where it comes into contact with air. From there, a fan circulates hot and cold air through the building’s ventilation system.

Water is distributed in a looped pipe system, so you don’t generally need to replace the fluid. That said, nothing lasts forever, and eventually a pump or its connected parts can deteriorate.

Usually when chiller lines fail, water isn’t the issue. Instead, some other material has blocked it from passing through. Any number of materials can cause this blockage: dirt, debris, slag, plastic and even whole welding rods. Sometimes, initial installation, a lack of maintenance or a component failure can introduce these substances and cause a partial or total pipe blockage, preventing water from reaching the coils. Control valves or filtration can also fail in some capacity.

When a blockage or component failure occurs, it’s best to address it promptly, since catastrophic failure can contaminate the entire piping system. For this reason, contractors often give a system an initial flush while performing the finishing touches on a building. Maintenance crews also sometimes choose to flush their systems on a periodic schedule, such as summer for a boiler or winter for a chiller. A little preventative maintenance can go a long way.

Velocity is key

Generally, permanent pumps are designed to operate at a specific flow speed (or velocity) and a specific pressure. They’re not typically designed to run at a faster clip. Rather, they’re designed to run consistently for long durations, so they typically have a low tolerance for outside materials and pressure drops.

When it comes time to flush out a line, you usually need to source a different pump that can work with a higher velocity. By pushing water through faster, you can clear the lines from debris and various objects. Usually, a flush requires a velocity of at least six feet per second, but each system is different.

Pick your pump

Because HVAC systems are tailored specifically to a facility, there’s not usually a one-size-fits-all pumping solution. But Sunbelt Rentals can help. With a little bit of information, our Pump Solutions team can engineer the ideal solution for your system.

First, provide us with a diagram of the system, and our specialists will get to work. We’ll help you determine the proper velocity you need for a complete flush. With that knowledge, we’ll perform any and all calculations to identify a pump model that is right for the job and balances pressure and efficiency.

Flush it out

Once a pump is selected, we’ll handle all the transportation and onsite installation. Most setups and takedowns are completed within a day, though largescale facilities like data centers can require multiple pumps and a more complex setup process.

Because of the heavy-duty use and varying pressure changes, we use special hoses to control each chiller flush. It’s often smart to add filtration to assist in debris collection, and a flow meter can be installed to provide full visibility of your system’s velocity during a flush. When your system is fully installed, we’ll walk you through how to operate your pump.

When you begin to flush, try to stick to the recommended velocity. As tempting as it may be, there usually isn’t much to gain from running a pump at a faster speed than necessary. In most cases, this will simply burn more fuel.

Keep an eye on any filtration during the flush. Our specialists can show you what to watch for. Once a filter bag begins to fill up with debris, this will typically cause a pressure drop. When this happens, shut the system down and replace the bags.

After your lines are clear, we’ll work to ensure the debris is disposed of and your permanent system is filled to the ideal fluid level.

We'll keep you pumped up

Line flushes are just one part of what our pumps can handle. Our team engineers pumping solutions for a variety of fluids. Our models are built to help with sewer bypass, dewatering, oil spill containment and groundwater control.  And our in-house team of experts can offer guidance on just about any contracting job under the sun. Learn more about the Power of Sunbelt and request a quote today.

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