Product Overview

The Hayward Heat Exchanger Assembly for H400FD | FDXLHXA1400 is a genuine Hayward replacement heat exchanger designed for compatible Hayward H400FD Universal H-Series Low NOx pool and spa heaters. As one of the heater’s most important internal components, the heat exchanger transfers heat from the burner system into the pool or spa water, helping restore proper heater performance and consistent water temperature.

This replacement assembly is ideal for heater repair jobs where the original heat exchanger is leaking, corroded, damaged, or no longer heating efficiently. Designed specifically for the H400FD heater platform, this OEM Hayward part helps maintain proper fit, reliable operation, and factory-style performance.

Professional installation is strongly recommended due to the gas, water, and electrical components involved in heater service.

Ideal For

• Replacing a damaged, leaking, or corroded H400FD heat exchanger
• Restoring heat transfer performance in compatible Hayward heaters
• Pool and spa heater service repairs
• H400FD Universal H-Series Low NOx heater maintenance
• Customers searching by Hayward part number FDXLHXA1400
• Professional pool equipment technicians and service companies
• In-ground pool and spa systems using compatible Hayward H-Series heaters

Specifications

Key Features

Genuine Hayward Replacement Part

Manufactured by Hayward for proper compatibility with the H400FD Universal H-Series Low NOx heater.

Designed for H400FD Heaters

Made specifically for compatible Hayward H400FD pool and spa heater applications.

Restores Heater Performance

Helps restore proper heat transfer so the heater can warm pool or spa water efficiently.

Complete Heat Exchanger Assembly

Replacement assembly for the heater’s internal heat transfer system.

High-Flow Heating Design

Designed to support efficient water movement through the heat exchanger for reliable heating performance.

CPVC Union Plumbing Connections

Features 2" x 2.5" CPVC union-style plumbing connections for compatible heater installations.

Professional Repair Solution

Ideal for service technicians replacing a failed or damaged heat exchanger in the field.

Benefits

Helps Restore Consistent Water Temperature

A properly functioning heat exchanger allows the heater to transfer heat efficiently into the pool or spa water.

Extends the Life of Compatible Heaters

Replacing a failed heat exchanger can help keep an otherwise serviceable H400FD heater operating.

Reduces Heating Problems

Can help correct heater issues related to leaking, corrosion, poor heat transfer, or internal heat exchanger damage.

OEM Fit and Reliability

Using a genuine Hayward replacement part helps ensure proper fitment and compatibility.

Ideal for High-Demand Pool and Spa Systems

Built for the 400,000 BTU H400FD heater model commonly used on larger pools, spas, and combination pool/spa systems.

Customer-Facing Q&A

Q: What is the Hayward FDXLHXA1400 used for?

A: The Hayward FDXLHXA1400 is a replacement heat exchanger assembly for compatible Hayward H400FD Universal H-Series Low NOx pool and spa heaters.

Q: What is the SKU for this product?

A: The SKU is FDXLHXA1400.

Q: What is the UPC / barcode?

A: The UPC / barcode is 610377073752.

Q: Is this a complete pool heater?

A: No. This is a replacement heat exchanger assembly only. It is not a complete heater.

Q: Which heater does this fit?

A: This part is designed for the Hayward H400FD Universal H-Series Low NOx heater. Always confirm your heater model number before ordering.

Q: Will this fit H250FD, H300FD, or H350FD heaters?

A: No. This listing is for the H400FD heat exchanger assembly. Other heater sizes typically require different heat exchanger assemblies.

Q: When should a heat exchanger be replaced?

A: A heat exchanger may need replacement if it is leaking, corroded, cracked, damaged from poor water chemistry, or no longer transferring heat properly.

Q: Can a homeowner install this part?

A: Professional installation is recommended. Heater repairs may involve gas, water, electrical, venting, and safety controls.

Q: What should be checked before installation?

A: Confirm the heater model number, inspect the burner system, check for water chemistry damage, verify plumbing condition, and ensure all safety controls are operating correctly.

Installation Notes

• Turn off gas, power, and water flow before servicing the heater.
• Confirm the heater model is H400FD before ordering or installing.
• Inspect the heater cabinet, burner tray, headers, sensors, wiring, and plumbing unions during repair.
• Check pool water chemistry history, as poor water balance can damage heat exchangers.
• Replace damaged seals, gaskets, or related hardware as needed.
• Installation should be completed by a qualified pool heater technician.
• After installation, test for leaks, proper ignition, safe operation, and correct water flow.