Why Are 4,600 Hayward Pool Heaters Being Recalled for Carbon Monoxide Risk?

Hayward Industries has recalled about 4,600 Universal-HC Series pool heaters because they can produce dangerous levels of carbon monoxide during normal operation. The recall covers units sold between March and July 2026 for roughly $5,600 each.

What the heater looks like and how to spot it

The HDFS400 is a 400,000 BTU dual-fuel gas heater. It stands 31 inches high, stretches 28 inches wide, and runs 21 inches long. Brown cabinet, black top. A digital display panel sits on the upper face. The base is molded with built-in tie-down points. Look at the name plate below the vent: "Hayward" prints at the bottom, "HDFS400" at the top. That plate is the fastest way to confirm whether your unit falls inside the recall.

How carbon monoxide builds up

Carbon monoxide forms when fuel burns without enough oxygen. In a properly tuned heater the burner mixes gas and air at a ratio that leaves almost no CO in the exhaust. The recall notice says these units "can produce high levels of carbon monoxide during operation." It does not describe the root cause — a blocked venturi, a faulty gas valve, a software error in the ignition sequence — only the result. CO has no smell, no color, no taste. It displaces oxygen in blood. At high concentrations it kills in minutes. The hazard exists whenever the heater runs, whether the pool is in use or the unit simply maintains temperature.

Stop using it now

Do not wait for a weekend. Do not run it "just one more time."

What the recall requires you to do

Contact Hayward Industries at 855-500-5288 between 8 a.m. and 5 p.m. Eastern time, Monday through Friday. Email works too: HeaterInquiry@Hayward.com. The company website has a recall page at hayward.com/productrecall and a banner on the homepage labeled "Recall Information." A qualified technician will visit your home, inspect the unit, and repair it at no cost. The notice does not say what the repair entails. It does not say how long the fix takes. It does not say whether the technician replaces parts, adjusts calibration, or updates firmware.

Scope and timeline

About 4,600 heaters entered the market. They moved through pool equipment distributors, builders, and service professionals nationwide. The sales window ran from March 2026 through July 2026. That is a five-month span. Every unit was made in the United States by Hayward Industries, Inc., based in Charlotte, North Carolina. The recall carries number 26-777 and was announced September 17, 2026. No injuries have been reported. No incidents have been reported. The notice simply states the hazard exists and the remedy is a free in-home repair.