Boiler Leaking Water From The Overflow Pipe? (Fix It Now!)

Upgraded Home Team
by Upgraded Home Team

You may be surprised how many appliances and items in the home resemble each other in a working fashion. One thing, in particular, is found on most devices and vanities in the house. An overflow pipe is a lifesaver when problems arise with anything dealing with water, but what if your boiler starts leaking water from the overflow pipe?

The boiler leaks water from the overflow pipe when there’s too much pressure, either from a failing expansion vessel or the vessel loses its charge. Or, the pressure relief valve might be incorrectly seated, allowing water to run by it. Prevention and repairs on these two primary causes can save a fortune in other maintenance.

It is interesting to know that many items have overflow pipes, not just your boiler. Various fixtures and appliances have a similar setup for overflow pipes, and understanding them can help you repair them.

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Understanding An Overflow Pipe And Boiler System

A boiler system is an appliance that is often confused with boiling water. The confusion came from the past term when boiling water is turned into steam from boilers. Today’s boiler systems operate on natural gas or electricity and are water heaters made to heat the home.

The boiler system heats the water from 145-190 degrees. It operates on radiant heat, in which objects in a room absorb heat at a slower pace. They can make a room feel warmer than the air temperature, and people prefer this method with better efficiency.

The two methods of heating a home are boilers and furnaces. They both produce heat throughout the right-sized house, but the boiler heats the home through pipes and steam. A furnace will use a blower to push the warm air through the vents.

An overflow pipe is designed to keep tanks from overflowing and damaging the floors and walls. There are times when tanks, sinks, and toilets will continue to run, and the excess water has to go somewhere. The overflow pipe either leads to the outdoors away from the home or to the sewage system.

Sometimes the overflow pipes may fail and leak water defeating the purpose. It is an unexpected event that needs to get repaired immediately. We will go through the causes and fixes in this article.

The Pros And Cons Of Using A Boiler

Many people are moving toward boilers, but some still prefer what they have with their furnaces. These are the good and bad points of having a boiler system. Here are some of the advantages:

  • No air is forced through any system, so no allergens or dust are being pushed around.
  • Boiler systems are quiet, and you will never hear when the system kicks on.
  • Boiler systems are used to heat the floors using radiant air through floor pipes.
  • They can last up to 30 years if well maintained.

Conversely, here are some cons of a boiler system.

  • The pay upfront cost is more than a furnace.
  • Since the system operates on the heating of water, any leaks can cause a mess.
  • Also, the water may freeze in pipe bursting temperatures if the power goes out.

The Boiler Leaking Water From The Overflow Pipe

The overflow pipe on a boiler system is technically not an overflow pipe like the rest of the tanks. It acts more like a pressure relief valve when the boiler accumulates too much pressure. The valve will release some water out of the overflow pipe to relieve the pressure.

There is a condensate pipe that should not be confused with the overflow pipe. The overflow pipe is copper and extends to the outside of the home. The condensate pipe is made of plastic and ties into a sewage line.

These are the two primary causes the overflow pipe may leak water.

  • When too much pressure accumulates in the boiler, water may leak out the overflow pipe. An expansion vessel may have failed.
  • If the pressure relief valve is not appropriately placed, water may leak from the overflow pipe.

It is highly recommended to contact a professional to handle the job of repairing the water leak. Boilers are extremely dangerous to repair. It is essential to find out exactly where the leak is coming from before any decisions are made.

The steps are so dangerous; all DIY websites do not detail how to repair the overflow leaks on boilers. Every site says to search for a Gas Safe Registered Boiler Engineer. Severe burns and explosions are possible if you have never repaired overflow pipes before.

Tips To Prevent Boiler Leaking Water From The Overflow Pipe

Everything in the home and appliances need maintenance for them to work correctly and last longer. There are seven suggestions to keep up with the care of the boiler system.

1. Bleed The Radiators

Bleeding the radiators every so often can add life to the boiler system. It will also remove any cold spots and keep the system running efficiently.

2. Fix Any Leaks You May Find

Any leaks you may find around the tank or pipes, fix them immediately. This will also help prevent corrosion, messy or rotten floors, and keep the system operating at total capacity.

3. Look for Sooty Black Marks

As you are giving the boiler system a checkup, look for black sooty marks. If some are visible, there may be a combustion problem. This problem must get fixed immediately due to the hazards involved.

More Tips For Preventing Boiler Leaking Water From The Overflow Pipe

4. Check the Pilot Light Is Working Properly

The pilot light should always be on and burning a bright blue. If the color changes to orange or yellow, contact professional assistance immediately.

5. Noise Is A Bad Thing With Boilers

Boilers are meant to be quiet. If you hear noise coming from the pipes or the boiler, there may be a breakdown fixing to happen.

6. Make Sure The Thermostat Is In Working Shape

There are a few things in maintenance you can do to keep the thermostat working properly. Most of the time, the thermostat is found in the hallway. Keep it clean, keep the batteries fresh if they have some, and always keep up with the temperature readings.

If anything is off on the temperature readings, that is a good indicator there is a problem with the boiler. It can also mean the thermostat is going out, and the system will malfunction. Older thermostats may lose accuracy, so always be on the lookout.

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What To Do When You Find A Puddle Of Water Behind The Boiler?

As mentioned earlier, the only thing a homeowner can do is the maintenance of the boiler system. It is highly recommended no repairs be done by someone other than someone certified. However, it is the homeowner’s responsibility to spot any leaks and report them immediately.

There are various things that can cause leaking besides your boiler leaking water from the overflow pipe. The overflow pipe is only one place water may come from when the system is leaking. Here are some other causes and areas to check up on when doing your maintenance checks.

1. Check All The Pipework

The pipes that are directly underneath the system will be the ones to cause problems first when it comes to leaking. Corrosion is the primary reason for these leaks. Most of these problems will begin after the system is ten years or older.

2. Check The Pressure Gauges

If there is too much pressure, the excess water will escape either from the overflow pipe or through another line. All combi boilers and system boilers have pressure gauges. The regular reading will stay in the green area around the one bar.

If the gauge moves closer toward the red after 2.5, there will be problems. The pressure will build up and cause leaks or cause the internal parts inside the boiler to fail.

3. Check For Wear And Tear

The true sign of wear and tear is corrosion. If the lines are corroded, the price can be relatively low to repair with an engineer. Extensive corrosion will mean a new boiler system.

In some cases, an engineer may be able to save the system. Almost all of them will warn if the repairs are not worth it and cost more than a new boiler. The average cost is around $5,150 with a day of installation.

4. Leaking From A Faulty Heat Exchanger

The heat exchanger is the heart of the unit. If this goes, the chances are better to get a new system. However, this is another common place for leaks and all of the unit’s seals and joints.

Related Questions

What other appliances and fixtures use overflow pipes?

  • Toilets
  • Expansion and Cold Water Tanks
  • Expansion and Central Heating Feed Tanks
  • Copper Cylinder
  • Combination Boilers
  • Basins, Sinks, and Bathtubs
Can I use a leaky boiler?

No. A leaky boiler is unlikely to keep you warm anyway, and there could be something serious going on that could lead to irreparable damage. If you notice a leak or something off with the pressure, turn off the water supply and central heating. Contact a Gas Safe engineer immediately to repair or replace the boiler.

Upgraded Home Team
Upgraded Home Team

We are a team of passionate homeowners, home improvement pros, and DIY enthusiasts who enjoy sharing home improvement, housekeeping, decorating, and more with other homeowners! Whether you're looking for a step-by-step guide on fixing an appliance or the cost of installing a fence, we've here to help.

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