Product Overview

The Hayward FDXLHXA1300 Heat Exchanger Assembly is the genuine OEM replacement heat exchanger for the Hayward Universal H-Series H300FD Low NOx pool and spa heater. Rated for the 300,000 BTU/hr platform, it transfers heat from the combustion chamber into the circulating pool or spa water. It is the part to order when a qualified technician has confirmed that the original exchanger is leaking, scaled, corroded, or freeze-damaged and the rest of the heater remains fit for service, letting you restore heating without replacing the complete heater.

Ideal For

H300FD owners whose heat exchanger has failed while the burner, gas valve, and controls remain serviceable.

Pool and spa service professionals completing a confirmed heat exchanger repair on an H300FDN or H300FDP heater.

Customers who want a factory part matched to the 300K H-Series platform rather than replacing the complete heater.

Key Features

Genuine Hayward OEM replacement heat exchanger assembly.

Designated by Hayward for the H300FD 300,000 BTU/hr heater size.

Cupro-nickel exchanger construction used across the Universal H-Series.

Plastic header configuration matching the H300FD platform.

Used in both natural gas (H300FDN) and propane (H300FDP) models.

Benefits

Restore heat transfer without the cost of a complete new heater.

Get factory-designed fit for the H300FD cabinet and connections.

Resist corrosion in demanding pool and spa water conditions.

Return the heater to service with the same assembly Hayward specifies.

Specifications

What's Included

One Hayward FDXLHXA1300 heat exchanger assembly. The complete heater, burner assembly, gas valve, and electronic control system are not included.

Warranty & Compatibility

Important Purchase Notice

This is a major heater-repair component. Hayward requires installation by a qualified pool heater professional, and proof of professional installation may be needed to keep manufacturer warranty coverage. Confirm your complete heater model and serial number, the existing exchanger part number, and the applicable warranty terms before ordering.

Compatibility

The FDXLHXA1300 is designed for the Hayward Universal H-Series H300FD heater, including H300FDN (natural gas) and H300FDP (propane) configurations. Match the complete model and serial number on the heater data plate against Hayward's parts diagram before ordering.

Hayward uses a different heat exchanger assembly for each heater size. FDXLHXA1150 fits the H150FD, FDXLHXA1200 the H200FD, FDXLHXA1250 the H250FD, FDXLHXA1350 the H350FD, FDXLHXA1400 the H400FD, and FDXLHXA1500 the H500FD. Do not select a heat exchanger based on physical appearance alone.

Older Millivolt, ED1, and ED2 heaters, and ASME-configured commercial heaters, use different assemblies. Verify the heater data plate when an ASME configuration may apply.

Installation and Upgrade Context

Replacing a pool heater heat exchanger requires substantial disassembly and should be completed by a qualified pool heater professional following Hayward's service instructions. Before service, disconnect electrical power, shut off the gas supply and circulation pump, let the heater cool completely, relieve system pressure, and drain the exchanger.

During replacement, inspect the inlet/outlet header, bypass components, O-rings, temperature sensors, water-pressure switch connections, and the combustion area. Identify what caused the original failure before returning the heater to service. Improper pH, low alkalinity, excessive sanitizer, scale, poor circulation, improper bypass operation, and freeze exposure are common causes, and correcting them helps protect the replacement exchanger.

Customer-Facing Q&A

Q: Which heater does the FDXLHXA1300 fit?
A: The Hayward Universal H-Series H300FD 300,000 BTU/hr Low NOx pool and spa heater.

Q: Does it fit both natural gas and propane models?
A: Yes. The same assembly is used in H300FDN natural gas and H300FDP propane configurations.

Q: Will it fit an H250FD or H350FD?
A: No. The H250FD uses FDXLHXA1250, and the H350FD uses FDXLHXA1350.

Q: Does this include the burner or control board?
A: No. It includes only the heat exchanger assembly.

Q: Can I install it myself?
A: Hayward requires installation by a qualified professional, and professional installation may be needed to keep warranty coverage.