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Why Is My Boiler Leaking Water? An NYC Plumber Explains

February 03, 2020


If your boiler is leaking water, there’s definitely an issue with your system. Boilers, by nature, are completely sealed and should never leak any type of liquid.

That said, if you’re dealing with a leaky boiler, you’re probably wondering what the issue is.

Your boiler could be leaking due to any of the following issues:

  • Faulty components 

  • Improper installation

  • Corrosion

  • Dry firing (firing boiler with no water)

To help you better identify what your particular boiler issue is, we’ll explore each of these issues below.

Want a professional to diagnose your boiler issue and correct the problem? Just contact Ranshaw. We’ve been serving NYC homeowners for 50+ years and provide fast, expert boiler repairs that are done the first time around—which saves you time and money.

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4 issues that can cause a leaky boiler

#1: Faulty Components

Sometimes, a leak in a boiler can be pinpointed down to a specific faulty component. That said, boiler components that commonly cause leaks over time include:

  • Valves

  • Pipe fitting/connections

  • Air vents

  • Circulator pump

  • Expansion tank

  • Low water cut off

#2: Improper installation

If your boiler is leaking from pipe fittings, the issue is likely a bad installation job.

If your boiler was installed recently, this might be your problem. If the contractor who installed the boiler system was rushing or simply installed the pipe fittings incorrectly, this will cause leaking in various parts of the boiler system.

The good news is that a professional can reinstall these pipe fittings correctly. However, if the leaking has gone on for some time, the pipes and other components may need replacement due to corrosion. 

#3: Corrosion

If you have an old boiler and it’s leaking from various places (vs from a single component), the system may have widespread corrosion.

As boilers age, the components of the system will begin to corrode due to exposure to water. Sometimes, corrosion will prevent itself in a single pipe or fixture, in which case a pro will usually be able to salvage the boiler by repairing or replacing that single component. However, older boilers with widespread corrosion will usually need to be replaced entirely.

#4: Dry firing

Another cause of a leaking boiler can occur when a boiler runs under low water conditions. This is referred to as dry firing. Dry firing can cause the boiler to overheat, resulting in cracks in the cast iron. 

Devices such as low water cut offs and automatic water feeders are designed to prevent low water conditions, thus preventing your boiler from dry firing. However, like any other mechanical device, failure can occur. If you notice cracks in your boiler and water leaking from the bottom of your equipment, shut down your boiler immediately and contact a qualified professional for help.

Need a professional boiler repair? Contact Ranshaw’s pros

Ranshaw has served NYC and surrounding areas for over 50 years. When homeowners in the area have boiler issues, they know to turn to Ranshaw for reliable and consistent service. 

When you call us, we’ll send over a licensed boiler professional fast to inspect and diagnose your system. We pride ourselves on performing high-quality boiler repairs that are done correctly the first time around. Plus, we offer 1-year labor warranty on all of our boiler repair work.


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