What to Do If Your Boiler Is Leaking

Boiler leaking in the basement of a residential home.

While a boiler leak isn’t necessarily an uncommon issue, it’s certainly still a concern. Though a lack of heating in your home seems like the most frustrating result, an untreated leak can lead to more extensive damage and create a potentially dangerous situation.

If you have or suspect you have a leaky boiler, and you’re not sure what to do, the information below will help. Although professional service is almost always needed in these cases, we’ve provided some helpful information for understanding and temporarily dealing with this issue.

Reasons Your Boiler May Be Leaking Water

There are many possibilities as to why your boiler is leaking, and internal issues are often less obvious. But aside from faulty installation or broken parts, a few other issues that can cause a water leak are:

  • High pressure. Though your pressure relief valves will occasionally drip when releasing necessary pressure, if an excessive amount of water is leaking, it could mean that pressure is too high, and your system is overworked.
  • High temperature. Your temperature control valve (TCV) will typically let you know when the water temperature is too high and prevent it from getting out of hand. However, if the sensors on your TCV are broken, the high temperature won’t be prevented, causing the water to boil over and leak.
  • Corrosion. While it’s anticipated that corrosion will occur inside your boiler (hence the anode rod), if water leaks out and corrosion begins externally, this wear can start to damage various parts, leading to further leaks and needed repair.
  • Damaged joints. Whether corrosion has caused some wear or the joints themselves have become loose, without a tight enough seal, water can begin to leak out of these cracks.
  • Old age. Your boiler doesn’t last forever, and old age can be the reason for cracks, failing parts, or overall slowed efficiency. A combination of these issues can cause functional errors that lead to overall damage and leaks.

Other reasons your boiler may be leaking can sometimes be identified through error codes. If your boiler has a display system, an error code may have appeared that you can cross-reference in your boiler’s manual.

Is a Leaking Boiler Dangerous?

A leaky boiler has the potential to not only cause a lot of functional damage but also pose a risk to you and your home if left unattended. In more severe cases, a water leak can corrode your system, short circuit electrical wiring, cause water damage to the walls or floor, and even spread to surrounding pipes or units. The aftermath can also be just as harmful if any water damage leads to mold or fungi growth. 

Gas or oil leaks from your boiler can be even more dangerous. If you’re dealing with an oil leak, make sure you close off your oil valve and collect the remaining oil in a tub before calling emergency service. A gas leak, however, requires more immediate attention, as the fumes can be a fire hazard and a danger to your health.

To take more preventive measures against gas leaks, follow our carbon monoxide safety checklist.

Related Topic: Catch the Culprits: Mold

How to Temporarily Fix a Leak Coming from Your Boiler

Due to the variety of issues that can occur, correctly identifying the source of the leak can be quite difficult. Because of this, troubleshooting on your own is not recommended. Most issues will require professional service to avoid hazards or further damage to your system. However, there are a few initial steps you can take before calling a service professional:

  • Turn off your boiler to eliminate electrical hazards and prevent further damage.
  • Mop/wipe up any leaking water on the boiler or floor and put a bucket under the leak if it continues.
  • Try to identify where the leak is coming from.
  • If the leak is coming from a loose joint, try tightening it and see if the leak stops.
  • If the leak doesn’t stop at the joint, you can try applying plumber’s tape to the leak before calling for professional service.

Permanent Fix and Maintenance

Whether the leak is big or small, a boiler leak is definitely a cause for concern. It can result in further damage to your boiler, your home, and create a hazardous situation. Following some of the steps above may help slow or stop the leak, but to ensure your boiler continues to work properly you will need to call in a professional.

A professional will be able to access the situation, offer a permanent solution and ensure the job is done safely. If you need help with a leaky boiler, call the local pros at Aire Serv, or schedule an appointment online.