Lochinvar Recalls Condensing Residential Boilers Due to Risk of Carbon Monoxide Poisoning

What was recalled

The U.S. Consumer Product Safety Commission has issued a recall affecting a significant number of residential heating units manufactured by Lochinvar. This action covers specific models of condensing boilers, combi boilers, and packaged systems that were sold for use in homes after August 2016. It is important to note that this recall is not limited solely to products bearing the Lochinvar brand name. The affected equipment was also distributed under the A. O. Smith and State Proline brand names. If you have one of these heating systems installed in your home, it is crucial to verify whether your specific unit falls within the scope of this safety notice, as the brands involved are often used interchangeably in residential plumbing and heating contracts.

The primary focus of this recall involves the identification of specific model numbers and serial number ranges that are at risk. The affected units include a wide variety of models, such as the ACB, KHB, SCB, WHL, WHN, APN, EPB, EPC, EPC110N-CAN, EPC150N, EPC199N, NKB, NKC, and WHB series. Because there are so many variations, checking the exact model number is the first step in determining if your boiler is part of this group. The recall specifically targets units with serial numbers falling within the range of 103475818 through 115078306. This precise numerical window helps narrow down which production batches are involved, ensuring that consumers can quickly determine if their specific unit needs attention.

To confirm if your boiler is included in this recall, you will need to locate the data plate on the product. This rating plate is typically found either on the outer jacket of the unit or on the underside of the removable front jacket plate. The brand name is clearly printed on the front of each unit, which can help you identify whether it is a Lochinvar, A. O. Smith, or State Proline model. Once you have identified the brand and located the data plate, you can compare your serial number against the recalled range. For those who do not know their installer or need further assistance in verifying their unit's status, consumers with Lochinvar-branded boilers can find a qualified service technician by visiting http://green.lochinvar.com/support/contractorlocator.aspx. Consumers with A. O. Smith or State Proline-branded boilers should contact their installer directly. If you do not know who installed your system, you can contact Lochinvar toll-free at 833-232-9706 for guidance.

This recall was announced on June 18, 2020, and affects units sold in the United States during the specified timeframe. The breadth of the model numbers involved suggests that these heating systems were widely distributed across the residential market over several years. By providing a clear list of model numbers and a specific serial number range, the CPSC aims to help homeowners quickly identify if their heating system is part of this recall. It is essential to act promptly, as the issue involves potential safety hazards related to carbon monoxide emission.

The hazard, explained

To understand why this recall is so serious, it helps to look at what happens inside a condensing boiler when things go wrong. These units are designed to be highly efficient by capturing heat from exhaust gases that would normally escape up a chimney. However, in the recalled Lochinvar models, a critical component called the flue grommet can deteriorate over time. Think of this grommet as a seal or a gasket that ensures all combustion byproducts stay contained within the unit’s internal pathways until they are safely vented outside.

When this grommet weakens and eventually dislodges, it creates an unintended opening in the system. Instead of traveling through the designated vent to the outdoors, carbon monoxide—a colorless, odorless gas produced by burning fuel—can leak into the surrounding air inside your home or building. This is not a slow seep; it can be a direct release of toxic fumes directly into the living space. Because carbon monoxide binds to hemoglobin in your blood much more effectively than oxygen does, even small amounts can prevent your body from getting the oxygen it needs. This leads to symptoms that range from headaches and dizziness to confusion, loss of consciousness, and death.

The records indicate that this physical failure has already occurred in real-world settings. The manufacturer has received seven reports of these flue grommets deteriorating. Most concerningly, one report involved two non-fatal injuries due to carbon monoxide poisoning, while two other reports confirmed that the boilers were emitting carbon monoxide without causing immediate injury. These incidents highlight that the risk is not just theoretical; the seal can fail during normal operation, turning a heating system into a silent source of poison.

Why is this particularly dangerous? Carbon monoxide is often called the "silent killer" precisely because you cannot see it or smell it. You might feel fine initially, only to become increasingly lethargic or confused as levels rise. In the case of these boilers, the failure happens during use, meaning the hazard is active whenever the heating system is running. If the leak occurs in a tightly sealed home, especially during winter months when windows are closed and ventilation is minimal, concentrations of carbon monoxide can build up to lethal levels rapidly. This is why immediate repair is not just a convenience but a critical safety necessity.

Understanding this mechanism clarifies why simply turning off the boiler isn't enough if you suspect a leak—you need professional intervention to replace the damaged seal. The deterioration of the flue grommet is a physical breakdown that cannot be fixed by resetting controls or adjusting settings. It requires replacing the compromised part to restore the containment barrier between the combustion chamber and your home’s air supply.

Who is most at risk

While any household with the affected Lochinvar boilers faces a serious safety threat due to the potential for carbon monoxide leakage, certain groups of people are physiologically more vulnerable to its effects. Carbon monoxide is often called the "silent killer" because it is colorless, odorless, and tasteless, making it impossible to detect without specialized equipment. When the flue grommet deteriorates and dislodges, combustion gases that should have been vented outside can seep back into your living space. For most healthy adults, mild exposure might cause headaches or nausea—symptoms that are easily mistaken for the flu or fatigue. However, for specific populations, even low levels of exposure can lead to rapid deterioration of health.

Young children and infants are particularly at risk because their bodies process carbon monoxide differently than adults. They have a higher metabolic rate, meaning they breathe in more air relative to their body weight. This allows the toxic gas to enter their bloodstream faster. Additionally, their developing organs and brains are more sensitive to oxygen deprivation. Because young children cannot always articulate that they feel "off" or have a headache, symptoms like lethargy, confusion, or vomiting may be overlooked until the condition becomes severe.

The elderly and individuals with pre-existing heart or lung conditions also face heightened danger. For someone with coronary artery disease, carbon monoxide binds to hemoglobin in the blood more readily than oxygen does, reducing the amount of oxygen available to the heart muscle. This can trigger angina (chest pain) or even a heart attack, even at exposure levels that might only cause mild discomfort in a healthy person. Similarly, people with chronic obstructive pulmonary disease (COPD) or asthma may find their respiratory distress exacerbated significantly by reduced oxygen saturation in the blood.

Pregnant women and their unborn babies are another critical group at risk. Carbon monoxide crosses the placenta easily, and fetal hemoglobin has an even stronger affinity for carbon monoxide than adult hemoglobin does. This can lead to lower oxygen levels for the developing fetus, potentially causing developmental issues or other complications. Because the symptoms of carbon monoxide poisoning in pregnant women (such as headache and dizziness) mimic common pregnancy complaints, it is crucial not to dismiss them. If you fall into any of these categories, immediate action is essential. Do not wait for severe symptoms to appear; rely on your carbon monoxide alarms and the free repair service offered by Lochinvar to keep your home safe.

How to tell if you have the recalled item

Identifying whether your heating system is part of this recall requires a bit of detective work, but the process is straightforward if you know exactly where to look. The primary challenge here is that these boilers were sold under three different brand names: Lochinvar, A. O. Smith, and State Proline. This means you cannot rely solely on the logo or nameplate at the front of the unit to determine if it is affected. Instead, you must verify the specific model number and serial number against the official recall list.

The first step is to locate the data plate, which serves as the product’s identification card. On these units, the brand name is printed clearly on the front. However, the critical information—the model and serial numbers—is found on the rating plate. This plate is typically located either on the outer jacket of the unit or on the underside of the removable front jacket plate. You may need to remove a panel or look closely at the sides and bottom of the boiler to find this label. It is essential to check both the model number and the serial number, as the recall applies to a specific range of serial numbers.

The recalled units are residential condensing boilers, combi boilers, and packaged systems sold after August 2016. The serial numbers for these affected units fall within the range of 103475818 through 115078306. If your unit’s serial number is outside this range, it is not part of this specific recall. For those who prefer a digital verification method, you can check for the recalled boilers’ serial number at www.waterheaterrecall.com. Simply select the look-up feature for the flue grommet recall to confirm your status.

Below is a list of the model numbers included in this recall. If your unit’s model number matches any of the following, and the serial number falls within the specified range, you need to take action immediately:

• ACB KHB (Cont.)
• SCB WHL
• ACB110H-N
• KHB285L-8647
• SCB110H-N
• WHL156-8647
• ACB110H-P
• KHB285N
• SCB110H-P
• WHL200
• ACB110S-N
• KHB285N-001
• SCB110S-N
• WHL286
• ACB110S-P
• KHB285N-002
• SCB110S-P
• WHL286-8647
• ACB150H-N
• KHB285N-8018
• SCB150H-N
• ACB150H-P
• KHB285N-8647
• SCB150H-P
• WHLN
• ACB150S-N
• KHB285N-8710
• SCB150S-N
• WHLN056
• ACB150S-P
• KHB285N-M7
• SCB150S-P
• WHLN056-8647
• ACB199H-N
• SCB199H-N
• WHLN086
• ACB199H-P
• NKB
• SCB199H-P
• WHLN086-8647
• ACB199S-N
• NKB050L
• SCB199S-N
• WHLN111
• ACB199S-P
• NKB050L-8647
• SCB199S-P
• WHLN111-8647
• APN
• NKB050N
• WHB
• WHLN156
• APN285
• NKB050N-8647
• WHB055L
• WHLN156-8647
• EPB
• NKB080L
• WHB055N
• WHLN200
• EPB080N
• NKB080L-8647
• WHB055N-8647
• WHLN200-0119-002
• EPB110N
• NKB080N
• WHB085L
• WHLN200-8647
• EPB110N-CAN
• NKB080N-8647
• WHB085N
• WHLN286
• EPB150N
• NKB110L
• WHB085N-8647
• WHLN286-M7
• EPB199N
• NKB110L-8647
• WHB110L
• WHLN286-001
• EPC
• NKB110N
• WHB110N
• WHLN286-8647
• EPC110N
• NKB110N-8647
• WHB110N-8647
• EPC110N-CAN
• NKB150L
• WHB155L
• EPC150N
• NKB150L-8647
• WHB155N
• EPC199N
• NKB150N
• WHB155N-8018
• KHB
• NKB150N-8647
• WHB155N-8647
• KHB055L
• NKB199L
• WHB199L
• KHB055N
• NKB199L-8647
• WHB199N
• KHB055N-8647
• NKB199N
• WHB199N-8018
• KHB085L
• NKB199N-8647
• WHB199N-8647
• KHB085N
• WHB285L
• KHB085N-8647
• NKC
• WHB285L-8647
• KHB110L
• NKC110L
• WHB285N
• KHB110N
• NKC110L-8647
• WHB285N-0119-001
• KHB110N-

  What to do — step by step

  If you own one of the recalled Lochinvar residential condensing boilers, combi boilers, or packaged systems, your immediate priority is safety. The hazard involves a deteriorating flue grommet that can dislodge and allow carbon monoxide to escape into your home. Because carbon monoxide is an odorless, colorless gas that can be fatal, you must treat this situation with urgency but without panic. Here is exactly what you need to do, in order, to protect yourself and your household. First, if you have any doubt about whether your unit is part of this recall, verify the model and serial number immediately. You can check for the recalled boilers’ serial number at www.waterheaterrecall.com by using their look-up feature specifically for the flue grommet recall. Look at the data plate on your unit, which is located on the outer jacket or the underside of the removable front jacket plate. Confirm that the model number matches one of the listed models (such as ACB, KHB, SCB, WHL, etc.) and that the serial number falls within the range of 103475818 through 115078306. If you are unsure, it is always safer to assume it might be affected and proceed with the verification steps below. Second, do not attempt to repair the boiler yourself. This is a complex mechanical issue involving gas combustion and exhaust systems that requires specialized knowledge. Instead, you should immediately contact the installer who originally installed your unit or hire a qualified technician to schedule a free repair. The remedy provided by Lochinvar is a free repair, so you should not be charged for parts or labor associated with fixing the flue grommet issue. Third, if you cannot reach your original installer, or if you do not know who installed the unit, you must contact Lochinvar directly. Call their toll-free number at 833-232-9706 between 8 a.m. and 8 p.m. ET, Monday through Friday. If your boiler is branded Lochinvar, you can also find a qualified service technician by visiting http://green.lochinvar.com/support/contractorlocator.aspx. However, if your unit is branded A. O. Smith or State Proline, you should contact your installer directly. If you do not know your installer for these brands, call the Lochinvar number above for assistance in locating one. Fourth, while you await the scheduled repair, take specific safety precautions. Continue use of the boilers only if you have working carbon monoxide alarms installed outside of sleeping areas and on every level of your home. These alarms are your primary defense against undetected carbon monoxide leaks. Ensure they are functioning correctly and have fresh batteries. If any alarm sounds, evacuate your home immediately and call emergency services from a safe location outside. Do not re-enter until professionals confirm it is safe. Finally, keep records of all communications with installers or technicians. Document the date you reported the issue and the appointment scheduled for the repair. This ensures you are covered under the free remedy program and provides a paper trail if any questions arise later. By following these steps carefully, you ensure that your home remains safe while the manufacturer addresses the defect at no cost to you.

  Your refund, repair, or replacement options

  If you have confirmed that your heating unit is part of this recall, the most important thing to know right now is that you are not left to handle this safety issue on your own. The manufacturer, Lochinvar, has established a clear remedy for all affected consumers: they will provide a free repair. This is not an optional courtesy; it is the official corrective action mandated by the recall. The goal of this repair is to address the specific mechanical failure—the deteriorating flue grommet—that allows carbon monoxide to escape into your living space. By fixing this component, the manufacturer aims to restore the boiler’s integrity and ensure that exhaust gases are properly vented outside, rather than leaking back into your home.

  To access this free repair service, you need to take a specific first step: contact your installer or a qualified HVAC technician directly. You should schedule an appointment specifically to mention that you have a recalled unit and require the manufacturer-sponsored repair. It is crucial that you do not attempt to fix this yourself. The flue grommet is a critical part of the combustion system, and improper handling could worsen the leak or create new hazards. A professional technician will know how to safely access the unit, verify the serial number against the recall database, and install the necessary replacement parts at no cost to you.

  If you are unsure who installed your boiler, or if you cannot reach your original installer, Lochinvar has provided a direct line of support. You can call their toll-free number at 833-232-9706. Their customer service team is available from 8 a.m. to 8 p.m. Eastern Time, Monday through Friday. If you have a Lochinvar-branded unit, the company also offers an online contractor locator tool at http://green.lochinvar.com/support/contractorlocator.aspx to help you find a qualified professional in your area. However, if your boiler is branded as A. O. Smith or State Proline, the instructions specify that you should contact your installer directly. In cases where you do not know who installed these specific brands, you are encouraged to call Lochinvar at the same toll-free number for assistance in locating service.

  Please note that this recall remedy focuses exclusively on repair. The facts provided do not mention options for a full refund or a complete replacement of the entire unit. The company’s approach is to fix the defective component so that your existing system can continue to operate safely. While this may feel like an inconvenience, it is a standard and effective way to resolve manufacturing defects in complex mechanical systems without requiring you to purchase entirely new equipment. The free repair covers both the parts and the labor required to replace the deteriorating flue grommet. Once the repair is complete, your boiler should no longer pose a risk of carbon monoxide emission. Until that repair is made, however, you must treat the unit as unsafe for continuous use without proper monitoring.

  What can happen if you ignore it

  Ignoring a recall notice for a carbon monoxide emitting boiler is not merely an administrative oversight; it is a decision to live with an active, invisible threat inside your home. The core issue with the recalled Lochinvar, A. O. Smith, and State Proline condensing boilers is mechanical failure. Specifically, the flue grommet—a critical component that seals the exhaust path—can deteriorate and dislodge during normal operation. When this happens, the seal breaks. Instead of safely venting toxic combustion gases out through your chimney or exterior wall, carbon monoxide (CO) leaks back into the living spaces where you breathe.

  The consequences of this failure are severe because carbon monoxide is often called the "silent killer." It is a colorless, odorless, and tasteless gas. You cannot see it, smell it, or detect it with your senses. If the grommet fails and you continue to use the boiler for heat or hot water, the concentration of carbon monoxide in your home can rise to dangerous levels without any warning signs. This creates a situation where you and your family could be exposed to lethal concentrations of gas while sleeping, working, or simply relaxing in your own home, completely unaware that the air is becoming toxic.

  We must look at what has already happened with these specific units to understand the real-world stakes. According to the Consumer Product Safety Commission (CPSC), this recall was prompted by actual incidents, not just theoretical risks. The manufacturer has received reports of flue grommets deteriorating in the field. More alarmingly, there have been confirmed reports of nonfatal injuries resulting from carbon monoxide poisoning linked to these defects. While the total number of reported injuries is currently listed as one instance involving two people, each of those incidents represents a life disrupted by illness, potential long-term health effects, and emergency medical intervention. There have also been additional reports of carbon monoxide emission that did not result in injury, likely because occupants noticed symptoms or alarms went off in time. These near-misses highlight how close to disaster the situation can be.

  If you ignore the recall and do not schedule a free repair, you are leaving this defect unchecked. The grommet does not fix itself; it will continue to deteriorate with every heating cycle. Eventually, the leak will likely become significant enough to saturate your home’s air. Carbon monoxide binds to hemoglobin in your blood much more effectively than oxygen does, essentially starving your organs and tissues of oxygen. Exposure can lead to headaches, dizziness, nausea, confusion, loss of consciousness, and death. By waiting, you are gambling with the safety of everyone under your roof. The only way to eliminate this risk is to stop using the faulty component’s path and have a qualified technician install the corrected part immediately.

  Staying safe: broader tips

  While this specific recall addresses a manufacturing defect in certain Lochinvar boilers, the underlying hazard—carbon monoxide (CO) poisoning—is a serious threat that extends to any home with combustion appliances. Carbon monoxide is often called the "silent killer" because it is completely odorless, colorless, and tasteless. You cannot detect a dangerous leak without specialized equipment. Therefore, relying on your nose or eyes to tell you if a boiler, furnace, water heater, or fireplace is leaking is a dangerous misconception. The only reliable way to protect yourself and your family from CO exposure in any home with fuel-burning appliances is through layered detection and regular maintenance.

  First, ensure you have working carbon monoxide alarms installed correctly throughout your home. Safety experts recommend placing at least one alarm on every level of your house, including the basement, and outside each sleeping area. This placement ensures that if a leak occurs in the living space or while you are asleep, you will be alerted immediately. It is crucial to test these alarms monthly by pressing the test button and to replace the batteries at least once a year, or when the device chirps a low-battery warning. Many modern alarms now have a ten-year sealed battery, which eliminates the need for annual changes but still requires replacement of the entire unit after its expiration date.

  Second, understand that carbon monoxide detectors are not a substitute for professional maintenance; they are a last line of defense. Combustion appliances like boilers and furnaces produce exhaust gases that must be safely vented outside through flues and chimneys. Over time, vents can become blocked by debris, nests, or ice, and internal components can corrode or crack. Schedule an annual inspection with a qualified HVAC technician who can check for proper draft, inspect the heat exchanger for cracks, and ensure all connections are secure. If you notice signs such as soot buildup around the appliance, a pilot light that frequently blows out, or excessive condensation on windows near the unit, have it serviced immediately.

  Finally, keep your home’s ventilation systems clear. Ensure that air intakes and exhaust vents for your heating system are not obstructed by snow, leaves, or other debris. Poor ventilation can cause combustion gases to back up into your living space rather than venting outside. By combining reliable detection devices with proactive professional care, you create a robust safety net that protects your home from the invisible dangers of carbon monoxide, regardless of the specific brand or model of your heating system.