What Causes Water Surging in a Steam Boiler and How to Prevent It

A common problem we see at Calray Boilers on our service calls is water surging in a steam boiler. In this post, we help you identify surging, discuss its causes, and offer advice on how to prevent surging in your boiler system. Failure to treat and prevent surging can cause a host of unwanted consequences, which we also address below.

What Is Surging in a Steam Boiler?

Unstable water

If you’ve seen or heard surging in your steam boiler, you probably won’t forget it. This is when the water levels in the boiler fluctuate violently, like the sea during a storm. The water moves up and down and may appear to “percolate” like in an old-fashioned coffee maker (see below).

What is the physical mechanism behind surging? As we review in the next section, surging is most often caused by grease, oil, or detritus accumulating on the surface of the water inside the boiler tank. As steam struggles to lift from the surface during the evaporation process, it causes the dramatic motion of the water.

You might see the word “surging” used interchangeably with “priming,” which is essentially the same thing. Sometimes “priming” is the step before “foaming,” which is another unwanted boiler issue.

What Causes Surging in a Steam Boiler?

Numerous causes

There are multiple things that can cause boiler surging. The most common ones we witness with our New York City clients include:

• Failure to clean a newly installed boiler, leaving grease, oil, and debris in the boiler water
• Lapsed maintenance, including cleaning, on a boiler that’s been in use for a while
• Dirty water in the boiler, including oil leaks and particulate matter from the water source
• The wrong size burner was installed with the boiler
• The burner is set too high (AKA “overfiring”)
• High water pH (basic water versus acidic, which can also cause foaming)
• Wrong size or incorrectly installed Hartford loop (extra safety loop outside the boiler between the steam main and the cold return)
• Undersized piping leading from the boiler, which pulls steam at a higher velocity than it should and results in both surging and water hammer

As you can see, there are many places where you can go wrong, resulting in surging. We frequently observe more than one of these causes contributing to surging simultaneously. That’s why we so adamantly stress regular boiler maintenance and professional installation by a reputable boiler expert.

Why Is Water Surging Bad for Your Boiler?

Inefficient and costly

Water surging in a steam boiler is not something you want occurring with your system because of its many negative consequences. Surging can, in turn, cause flooding in a steam boiler, which means the water level is dangerously high. This happens because the precipitous changes in water level that occur with surging momentarily make it look like the water level is too low. So, the sensor triggers more filling of the boiler from the automatic water feeder when it isn’t actually needed.

Flooding has unwanted consequences of its own. Both surging and flooding can result in excess wear and tear on the boiler’s sensors that detect the water level. On the remote end of your boiler system, surging and/or flooding result in poor steam production and spitting radiators. Tenants may complain about suddenly not having adequate or consistent heat.

Surging can progress to foaming. This occurs when dirty boiler water is present simultaneously with a high water pH. The water will have bubbles in it as if there were soap mixed in.

If surging happens regularly, it can cost you money as well. Your boiler may fire more often, using more gas and therefore running up your fuel bill. Furthermore, you’ll likely use more water, which is another expense.

As you can probably imagine, if the water surging in your steam boiler is caused by dirty water or debris inside the boiler, this may also shorten the lifespan of your entire boiler system. It puts stress on all the parts, including elements we haven’t mentioned yet, like the automatic water feeder.

How Do You Know If Your Boiler Is Surging?

Look and listen

There are a few different ways to tell if your boiler is surging. Your ears often give you your first clue, as you’ll hear the water churning and sloshing inside the boiler.

Next, look at your sight glass. If you see the water level going up and down dramatically, or if you see the water boiling like a percolator (especially if it looks oily or dirty), you’ve got a surging problem.

You might be in the early stages of surging if you find your boiler sensors triggering too often or unexpectedly. For example, the automatic water feeder might be filling the boiler tank more frequently than previously because it perceives a drop in volume.

Finally, you may hear from tenants that their radiators don’t sound right or that they’re spitting water. They may also say they don’t have enough heat.

How Do You Prevent Water Surging?

Regular cleaning and maintenance

It’s important to the integrity of your boiler that you don’t let surging happen in the first place and that you take care of it immediately if it does occur. Here are our recommendations for preventing water surging in a steam boiler:

• Make sure the boiler is cleaned regularly, including after installation and repairs and if you see the water in the sight glass looking dirty.
• In addition to cleaning, scheduled maintenance should be performed. We offer annual service agreements to make this even easier and more economical for you. This ensures parts like internal sensors and automatic water feeders are operating properly. We check to make sure your burner is functioning correctly and there are no oil leaks.
• Periodically check the water pH to make sure it’s not too high (basic). Correct the pH if it’s not between 7 and 9.
• Have a boiler professional check your Hartford loop and piping leading from the boiler to make sure they are sized and configured correctly.

Call Calray Boilers to Prevent Water Surging in Your Steam Boiler

New York City’s hyper-local blue-chip boiler experts

If you have experienced water surging in a steam boiler, or if you know your boiler system is due for preventive maintenance, we’re here to help. Call Calray Boilers at 212-722-5506, or use our easy online form today to schedule an appointment.