Pool heaters sold nationwide are pumping out carbon monoxide

Hayward Industries has recalled about 4,600 Universal-HC Series pool heaters after the Consumer Product Safety Commission determined that the units can give off high levels of carbon monoxide while they run. The recalled model is the 400,000 BTU HDFS400, a brown heater with a black top that moved through pool equipment distributors, builders and service professionals nationwide between March and July 2026 at about $5,600 each.

The recall, numbered 26-777, was announced on September 17, 2026. Hayward manufactures the heaters in the United States and is based in Charlotte, North Carolina. No injuries have been reported, which makes this a defect caught on paper and in testing rather than after a poisoning.

The HDFS400 and what CPSC found

The heater measures 21 inches long, 28 inches wide and 31 inches high, with a digital display control panel and a molded base with integrated tie-down connections. Those are the details CPSC lists in its recall notice for telling the recalled unit apart from other Hayward gas heaters. The notice limits the recall to the HDFS400 in the Universal-HC line, so other Hayward models and other brands are outside it.

The agency’s wording on the hazard is direct: during operation the heaters can produce high levels of carbon monoxide, “posing a risk of serious injury or death from carbon monoxide poisoning.” The notice stops short of a measured concentration, and it reports no incidents, so the claim rests on what the heaters can do rather than on a count of people harmed. Hayward’s own product recall page repeats the same description and the same instruction to stop using the unit.

One number invites confusion. Several local-television headlines on the recall carry the figure “400K,” but 400,000 is the heater’s BTU rating in the model name, not a unit count. The count in CPSC’s notice is “about 4,600,” a difference of nearly two orders of magnitude that changes how many households could be affected.

Carbon monoxide from a gas appliance

Carbon monoxide comes from incomplete burning of fuel, which is why a gas-fired heater is a candidate source whenever combustion goes wrong. The Centers for Disease Control and Prevention notes that the gas forms in the fumes of any burned fuel, including in stoves, lanterns, grills, furnaces and small engines, and that it cannot be seen or smelled. Its yearly tally for unintentional, non-fire poisoning is more than 400 deaths, more than 100,000 emergency department visits and more than 14,000 hospitalizations.

Pool heaters often sit in equipment pads, garages or enclosures beside a house, and exhaust that is not carried away cleanly can drift toward doors and windows. The recall notice does not describe where in the heater the extra carbon monoxide originates, and Hayward’s page gives no serial number ranges beyond the model designation.

Symptoms look like the flu, which is part of the danger. The Environmental Protection Agency’s carbon monoxide overview lists headache, dizziness, confusion and nausea at higher concentrations, and explains that the gas works by forming carboxyhemoglobin in the blood, which blocks oxygen intake. The CPSC’s carbon monoxide information center adds that more than 200 people in the United States die each year from non-fire carbon monoxide poisoning tied to consumer products, and that one portable generator produces as much of the gas as hundreds of cars.

Free inspection and repair through Hayward

Owners are told to stop using the heater immediately. Hayward will schedule a free in-home inspection and repair by a qualified technician, with questions handled at 855-500-5288 from 8 a.m. to 5 p.m. Eastern, Monday through Friday, or at [email protected].

The scale is modest next to the largest heater recalls. Each recalled unit carries a price near $5,600, and the March-through-July 2026 sales window means every heater was under eight months old when the recall was announced. The “nationwide” in the distribution line describes where distributors and installers sold the HDFS400, not a recall of every pool heater on the market, and the 4,600-unit total is the whole population CPSC counted.

Who is most exposed to a leak is spelled out by the CDC: infants, older adults, and people with chronic heart disease, anemia or breathing problems are more likely to become ill from carbon monoxide, and sleeping or intoxicated people can lose consciousness before noticing symptoms. The agency’s prevention advice is to place detectors near sleeping areas and to keep gas appliances vented properly. CPSC recommends battery-operated alarms on every level of a home and outside sleeping areas, and says interconnected alarms are best because when one sounds, all of them do.

As of the September 17 announcement, Hayward had no report of anyone harmed by an HDFS400, and for the owners of the 4,600 units the first step is a technician’s visit to the pool equipment pad.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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