Bad Check Valve Symptoms: 8 Reasons a Check Valve Fails

water heater check valve lg

Typical check valves only allow fluids to flow in one predetermined direction. And if they fail, you will have problems because the liquid or gas will flow where it is not supposed to.

Many reasons exist for check valve failures. Below are some of them:

  1. Worn out valve seat seals
  2. Debris within the pipeline
  3. Low flow
  4. High temperatures
  5. Poor installation techniques
  6. Poor maintenance
  7. Reverse flow
  8. Water hammer

It is crucial to understand how a check valve works to help you diagnose the symptoms that indicate something is wrong. Only then can you begin solving the problem in your home appliances.

This article discusses all these things and guides on all matters concerning check valves.

Reasons Why a Check Valve Fails

Depending on the appliance or drainage system, check valves fail for various reasons. Below are some of them:

1. Worn Out Valve Seat Seals

A check valve seat is an opening that will be closed by a ball or disc when the correct pressure is reached, thus preventing the flow of fluid in the unwanted direction. The valve seats are usually surrounded by seals, such as elastomer rings, to make them leak-proof.

Over time, due to age and friction, these valve seat seals degrade and become worn out. And they end up letting in some fluids through, which ends up affecting their integrity. As a result of that wear and tear, the check valve fails. And it may let in fluids partially or fully when it shouldn’t.

2. Debris Within the Pipeline

Debris within the pipeline refers to anything that should not be in there with fluids flowing through the check valve.

Any loose material that gets into the pipeline could affect its internal mechanism. And once that happens, the entire valve could fail, or its pieces could become dislodged and flow out without you realizing it until it is too late.

Pipeline debris could also lodge itself within the valve opening or exit. That, in turn, may make the valve either stay wholly open or closed and, thus, not function as it should to regulate the flow of water or gas.

3. Low Fluid Pressure

A pressure differential is critical to the functioning of a one-way valve. There is a minimum limit beyond which the valve cannot function.

Low flow could be the reason why your valve does not function well. In situations where the water flow has low pressure, it could be that the pipeline leading to it is too broad or clogged up.

For example, if the pipeline is clogged, the water pressure may not reach the cracking pressure required to open the valve because it slows down. So, in appliances like the washing machine, your check valve will reduce the rate at which it fills up.

Low fluid pressure could also force the valve diaphragm to remain more relaxed. As time goes by, the fluids passing through the valve will expose it to excess pressure, and the components will experience a lot of wear and tear and fail.

4. High Temperatures

Excessively high temperatures may also cause your check valve to fail. High temperatures tend to cause valve components to expand, lowering the fluid pressure and interfering with the inner workings.

In addition, high-temperature situations may degrade the valve components faster, thus compromising their ability to be leak-proof. That, in turn, will negatively affect the rate at which water or gas flows through the valve.

5. Poor Installation Techniques

The professional you hire to install a check valve will determine how well it performs. Typically, check valves vary in terms of size and type. They also differ in terms of what fluids they accommodate and how well they perform under different temperatures.

The professional who performs the installation should know the valve’s flow capacity, ideal orientation, and where to install the valve. That expert must also select a one-way valve of high quality so it can withstand wear and tear better.

Improper selection, assembly, and installation of your check valve will bring issues in the future.

For example, these valves have the flow direction stamped on their bodies. If the plumbing contractor fails to note that direction and installs the non-return vale facing the wrong way, the fluid may not even flow through it. That is because there will be inadequate pressure to force the valve open in the first place.

Alternatively, your contractor could install a horizontal lift check valve in a vertical position. Yet, they are designed for horizontal orientation since their seat lies parallel to the flow. By poorly installing it, your contractor will cause a perfectly new check valve to fail. And you may end up with an explosion you did not anticipate.

6. Poor Maintenance

Check valves require regular maintenance to continue functioning optimally. For starters, you could watch for signs of wear and tear within the valve. If the valve components have deteriorated, determine if you need to replace or repair them. Sometimes, the solution could be as simple as buying new seat seals to replace worn-out ones.

Also, look out for pipeline debris. If you notice any signs of floating objects in your fluid or destination tank, it could be a sign that debris may have lodged into the valve. A simple cleanup could solve the problem. However, you may need to replace the one-way valve.

You may also need to lubricate the valve components. And other valves may require some insulation to continue functioning well.

The general rule of thumb is to inspect your check valves twice each year, depending on the manufacturer’s recommendations. That ensures you catch any issues early enough to fix them.

Also, remember that a complete replacement is also part of regular maintenance. On average, a check valve lasts anywhere from five to seven years. But depending on other conditions, such as corrosion and pipeline debris, you may need to replace your valves earlier if they get damaged.

7. Reverse Flow

Reverse flow is a situation that arises when a pump trips out of service, causing water to lose pressure and reverse its direction.

As a result, the water waves crash through the piping and can cause plenty of damage to the check valves, which may fail to shut or experience erosion of its components over time.

8. Water Hammer

In a water hammer situation, fluids tend to stop or change direction suddenly while in motion. Such events can happen when pumps fail.

When that happens, a pressure surge occurs, spreads throughout the piping system, and it ends up colliding against the check valves. That pressure can be so great that it could damage the check valves, pipe walls, and other joints within the system.

Bad Check Valve Symptoms

When you have an issue with defective check valves, you will notice several symptoms. However, the signs will depend on why the valve has failed.

1. Poor Fluid Flow Symptoms

If you have an installation issue, you may notice that the fluid does not flow at all. That may happen if the contractor installs the wrong valve or puts it in the wrong orientation. Alternatively, you may realize that the amount of water or steam flowing through the valve is not as it should be. It could be less or more.

You may also notice a reduction in the rate of flow if you have a low-pressure issue. These signs could show themselves in various ways. For example, it may take longer for your washing machine to fill up. And the flow of water in your faucets could be down to a trickle.

Also, if you use a check valve to control water getting into your storage tank, you may realize that it takes much longer to fill up. Alternatively, water may not be flowing into the tank at all.

2. Noisy Symptoms

Water hammer issues are relatively easy to detect because they produce a hammering sound when pumps are in operation. That could be a result of the valve disc opening and closing all the time as water hits through it.

Whenever you hear sounds and feel vibrations in your piping as water flows, it could be a sign that your check valves have failed or are in the process of dying. So, you need to take a closer look.

3. Smelly Symptoms

If you smell dirty water, that could be a sign of check valve failure.

When check valves in your drainage systems fail, water will back up and show up in your sink, toilet, tub, or dishwasher. And that wastewater is what your nose will sense.

If a boiler is concerned, you may smell rotten eggs, which indicates that sulphuric gas is leaking. You may also notice a metallic odor, indicating deposits are forming somewhere within your boiler system, possibly even within your valves.

4. Heat And Energy Symptoms

If your energy bills are too high and there is no explanation, it could indicate that your check valves are malfunctioning. These may include water heater and boiler valves.

For example, if your boiler check valves have failed, your system may circulate water around your home even when your thermostat has not been set to send such instructions. There may be a pressure issue that valves are supposed to correct but are not doing so. As a result, your energy bills could rise significantly. And your home may end up warmer than you feel comfortable with.

5.   Visible Symptoms

Upon inspecting your valves, you notice that they stick, which means there is a problem that needs fixing. Sometimes the solution could be as simple as lubricating the valve components. You may also need to dislodge some debris to get the valve to function correctly again. But sticking could also indicate aging or corrosion.

Another symptom you may notice is visible wear and tear of components such as seat seals. In such cases, you need to replace those components. However, if the entire valve looks worn out, you will likely have to replace it.

In addition, if you see such things floating about in the water, you should assume that some parts may end up interfering with the valve mechanism. And if you have already noticed other problems such as slower water flow, the check valve is likely failing to function as it should.

Other visible symptoms include condensation where it should not be, pooling water on floors, and flooding.

6. Leaky Symptoms

If you notice that piping leaks from the joints, pipe walls, and other connections, it means the problem could be huge. Both water hammer and reverse flow may cause such issues.

And leakages tend to signal prolonged fluid pressure problem that you need to address as soon as possible because it has been left long enough to compromise the integrity of your plumbing.

7. Equipment Failure

If your valves fail for any reason, you may end up with equipment failure.

In that case, you may end up dealing with pump failure or an exploding boiler or hot water heater. Your pipes may also rupture and cause flooding.

When equipment fails due to a bad one-way valve, you should expect to pay thousands of dollars to fix the issue.

How Does a Check Valve Work?

A typical check valve has one inlet and one outlet. These two points allow the entry and exit of fluids, which could be water or gas, due to pressure differences between them. Generally, people sometimes refer to them as one-way or non-return valves because they force fluids to flow in one direction.

The pressure at the inlet should be higher for fluid to flow through it. The minimum pressure level that activates the valve and opens it is known as the cracking pressure. But the moment the pressure at the outlet exceeds the predetermined value, the valve closes.

You can find check valves anywhere where backflow is going to be an issue.

Which Home Appliances and Systems Contain Check Valves?

Many home appliances and systems benefit from the inclusion of check valves. These include the following:

  • Washing machines
  • Dishwashers
  • Fish tanks
  • Refrigerators
  • Boilers
  • Water heaters
  • Lawn sprinklers
  • Building drain systems

What Happens When a Check Valve Fails?

Considering the wide usage of check valves in your home, you should do everything you can to deal with any failures that arise as soon as possible.

Remember, when a check valve fails, it could have catastrophic consequences, depending on its location.

For example, if your drainage system check valves fail, you could have a backflow of contaminated water, which could end up mixing with your clean water supply. And should you consume that water, you will soon begin to deal with water-borne diseases.

Check valves also prevent wastewater from flowing back into your drainage system and causing flooding in spaces like the basement. If that happens, you should expect to pay anywhere from $3,000 to $10,000 on average to clean the mess up. And that is assuming you won’t have issues with the foundation or mold in the future.

It would help if you were also worried about a check valve failure in any boiler within your property. Generally, these valves help ensure that steam does not flow back into the boiler. They are also valuable for ensuring that boiler water is not forced back into the storage tank when the feed pumps stop operating. In addition, check valves help regulate the flow of steam and condensate within a boiler.

If a failure occurs concerning your check valves, a boiler explosion can occur. And it is also worth noting that defective or malfunctioning check valves can also cause water heaters to explode too.

In dishwashers, check valves help ensure that dirty water does not get back into the appliance and contaminate your dishes, which could make you sick.

And in your washing machine, failure of a check valve could affect the way water fills the machine, if at all. It may also impact the hot and cold water and whether they end up mixing. In addition, you may end up with flooding problems.

It is safe to say that the last thing you want is a check valve failing. For that reason, it would be wise for you to learn why your valves fail so you can know what to look out for.

Final Thoughts

Check valves are small pieces of equipment. It may be tempting to ignore them. But those tiny things determine how well bigger equipment or machines operate. So, ignoring them could cause you plenty of headaches and thousands of dollars of financial loss.

For that reason, you should inspect and maintain your check valves regularly. And where necessary, repair or replace the components or entire valve. The money you spend on maintenance and replacement is a worthy investment that could save your life.



Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.