Is It Normal For Your Steam Boiler To Lose Water?


Hydronic heating systems come in two general types: steam and hot water. Steam systems aren't prevalent, but you can still find them in many older homes. Steam systems rely on pressure to drive heat through your home. As your boiler turns the water to steam, it rises through the pipes and travels into your radiators. The water then cools, condenses, and drips back down to the boiler to start again.

Steam systems typically need a few more components to function correctly. Since the pipes may contain air, you'll usually find release valves on your radiators and various sections of your plumbing. These valves allow air to escape ahead of the steam but close before releasing any water. In other words, heating systems that use steam are "closed" and shouldn't lose water under normal conditions.

Why Is Your System Losing Water?

There's no getting around it: if you need to add water to your system, you have a leak. You can attempt to add a device that automatically adds water to your boiler when the level falls too low, but this approach is only a stop-gap measure. Since the system is closed, you should never need to add water to a steam boiler.

Fortunately, there aren't too many culprits when hunting down missing water in a home that uses a steam boiler. Leaks usually originate at one of three sources:

  • Air vents
  • Plumbing joints
  • The boiler itself

It's a good idea to check your air vents first. Dirty or clogged vents can sometimes stick open, allowing steam to escape along with air. You may hear a whistling noise when this happens, similar to the sound of a boiling tea kettle. Carefully check for any signs of moisture because the amount of water you're losing from a vent may be relatively small.

Joints between pipes are another common source of leaks. Check for signs of corrosion, moisture, or obvious leaks. Loud banging when your heating system runs is another indication that your problem may be with your pipes. Although leaks won't cause the banging, the force of air traveling through a sagging section of pipe can create gaps for water to escape.

Finally, leaks from the boiler itself can originate at the relief valve, pipe fittings, or even the pressure vessel itself.

Addressing Lost Water

Never assume that it's normal for your steam heating system to lose water. If you routinely add water to your boiler, you have a leak that may be causing significant hidden water damage in your home. A professional heating contractor can help you find and fix your leak, allowing your system to run more efficiently while also saving you from repairing expensive water damage.

Contact a local heating contractor to learn more.


2 December 2021

Plumbing Has Transformed Our Lives

Think about how different your life would be without plumbing. To get water, you would have to walk outside and pull it up from a well. To use the bathroom, you would have to venture out to an outhouse, which would certainly not be pleasant in the winter. We really have to thank plumbers for the work that they do, since it allows us all to stay comfortable and do our business inside of our homes. Life has been transformed, in so many ways, by the plumbing profession. Join us in honoring plumbers by reading the articles on this website.