Checking Your Condensate /Unit for Issues Checking Your Condensate Pump/Unit for Issues

While the basic principles behind commercial design have been in place for more than 150 years, modern are complex networks of machinery that require several systems working in concert to operate effectively. Neglecting any part of the system can cost businesses time and money. Therefore, it is vitally important to make sure all the elements of any boiler system, whether used for power generation, building heating, or other purposes, is functioning at peak efficiency. That includes seemingly innocuous components like the condensate pump, a critical but often overlooked part of every boiler system. Properly maintained steam traps can add to the life of your condensate unit but poorly maintained traps can become clogged trapping condensate and not allowing it to return to the unit causing very costly maintenance and repair.

To understand why condensate are so important, it’s first necessary to understand their function in the boiler system. Every steam boiler system is comprised of the heating vessel and four additional systems: distribution, feedwater, fuel and draft. The distribution system is the network that channels steam to whatever it will be used for — radiators, driving a turbine, etc. The feedwater system delivers to the heating vessel. The fuel system supplies the fuel that will burn and heat the water in the vessel. The draft system introduces the air for fuel combustion and vents the gasses created by it.

The distribution system is generally a closed system. Steam travels through it, and rather than being vented, it is reclaimed and sent back to the boiler, thus keeping water usage economical. As steam travels through the distribution system, part of it will cool enough to condense into water. This condensed water, or “condensate,” is typically collected in a receiver tank. Once enough water has been collected, a rising float in the receiver tank will trigger the condensate pump, which then pumps the reclaimed water back into the boiler for reuse.

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An easy way to picture how this process works is a familiar (if unglamorous) everyday example: a toilet tank. When activated, water flushes out of the tank into the bowl. As the tank is refilled, a float in the tank rises with the water level. When a sufficient amount of water has entered the tank, the float rises to the top and shuts off the flow of water into the tank.

To apply this example to modern boiler systems, the receiver tank is represented by the toilet tank, and the boiler is represented by the toilet bowl. And like this example, the condensate pump serves a simple but vital purpose: it makes sure that the water level is where it needs to be for the entire system to function at its best. When the condensate in the receiver tank reaches a certain level, the condensate pump is triggered and pumps the collected condensate back into the boiler for reuse.

So why is proper condensate pump function so critical? Imagine if the float in the toilet tank malfunctioned. Either too much water goes into the bowl (boiler) and it overflows, or not enough water gets to the bowl (boiler) and it runs dry. In a toilet, that is an inconvenience. In a boiler system, it is potentially disastrous. A boiler that has too much water in it will function poorly, which can result in huge dollar losses in reduced or lost production, and additional losses in downtime to fix the problem. A boiler that has too little or no water can be severely damaged, necessitating an expensive overhaul and/or replacement of critical components.

Condensate pumps may not be considered top priority items, but clearly it’s wise to make sure they are operating at peak efficiency. If you have any strainers attached to your condensate return be sure and check them weekly or monthly to ensure they are clean and free of any scale or other foreign material that can block condensate from returning to your unit.

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What should companies look for to ensure that they are? Here are some danger signs and their potential causes:

The pump runs too often or the pump motor overheats

• Make sure the capacity and pressure rating of the pump is appropriate. It may be insufficient for the task and needs to run too often to keep up. • Check the temperature of the condensate. These are superheated gasses and they may be overheating the pump. • Check the float switch. Remember the toilet tank example? If the float is stuck in the “on” position, it will keep running and continuously pump condensate to the boiler. • Ensure that the lines between the pump and boiler aren’t clogged. In systems with a lot of sediment in the water, adding new strainers or cleaning existing ones can help.

The pump constantly starts and stops, or doesn’t keep the boiler level high enough

• Again, check the float switch. It determines how often the pump runs and how much condensate is returned to the boiler each time it cycles. So it’s important that the float travel is set correctly. • Inspect the check valve. Condensate pumps have a one-way check valve that prevents water from flowing into the receiver tank from the boiler. If this valve doesn’t seal properly, water from the boiler will back up into the receiver and activate the pump. This can create a “tug of war” between the receiver and the boiler

Pump operation is excessively noisy

• Make sure the pump hasn’t been damaged by hot condensate or inadequate priming. • Check how the pump is mounted. It’s important to make sure that the pump controller is level and the pump is on an adequate foundation. • Is the noise coming from adjacent piping? Often, attaching short hoses between the input and output points can deaden knocking from pipes.

The pump leaks or functions erratically

• Check the PH of the water. Carbolic acid can build up in boiler systems and affect the seal. • Often, pump problems are caused by dirt and sediment, which can plug vent lines and clog the pump impeller

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Of course, setting the pump to run at maximum efficiency for a given application is the best way to avoid problems. Generally, the pump shouldn’t run more often than every three minutes. By adjusting float travel, it’s possible to get good results even with a pump with a relatively small gallon per minute rating. Here’s a handy table showing the relationship:

Pump Horsepower Building Capacity Gal per minute rating Approx. float travel and Tank Size Sq. Ft. EDR

1/3 HP with 8 gal steel or 8,000 12 3” 6 gal CI tank

2,000 3 3” 1/3 HP with 15 gal steel 4,000 6 5” or 13.5 gal CI tank 6,000 9 7” 8,000 12 8”

1/2 HP with 30 gal steel 10,000 15 7” or 24 Gal CI tank 15,000 22.5 10”

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