Product Overview

The Jandy Pro Series Heat Exchanger Tube Assembly | R0589405 is a genuine Jandy OEM replacement heat exchanger designed for compatible 400,000 BTU Jandy JXi and JXiQ gas-fired pool and spa heaters.

The heat exchanger is the primary component responsible for transferring combustion heat into the circulating pool or spa water. When the original exchanger develops a leak, excessive corrosion, scale buildup, or internal damage, replacing the heat exchanger can restore proper heater operation and heat-transfer performance.

Jandy specifically identifies R0589405 as the standard Model 400 heat exchange assembly. It is intended for compatible standard 400K heat exchanger configurations and should not be confused with the separate R0746905 cupronickel heat exchanger used on select 400K CuNi heater models.

Ideal For

• Jandy JXi 400K pool and spa heaters
• Jandy JXiQ 400K heaters
• Replacing a leaking heat exchanger
• Replacing a corroded heat exchanger
• Heaters with excessive internal scaling
• Restoring heat-transfer efficiency
• Residential pool and spa heater repair
• Professional Jandy heater service

Key Features & Benefits

• Genuine Jandy OEM Replacement – Engineered specifically for compatible Jandy gas heaters.
• 400,000 BTU Application – Designed for compatible JXi and JXiQ Model 400 heaters.
• Standard Heat Exchanger Configuration – Factory replacement for the standard 400K exchanger.
• Copper Heat-Transfer Construction – Provides efficient transfer of combustion heat to circulating pool water.
• Natural Gas & Propane Heater Compatibility – Used in compatible 400K heater configurations regardless of fuel type when the standard exchanger is specified.
• OEM Fit & Hydraulic Design – Maintains the heater's intended water flow and heat-transfer characteristics.
• JXi & JXiQ Compatibility – Appears in current Jandy parts documentation for both heater platforms.
• Professional Replacement Component – Ideal for qualified pool-heater technicians repairing existing Jandy equipment.

Specifications

POOL360 confirms the 43-lb weight, 24.5" × 20.75" × 19.5" shipping dimensions, Model 400 JXi application, and UPC 052337067157.

Compatible Heater Applications

Jandy JXi

JXi Model 400 / 400,000 BTU

Jandy's current gas-heater parts listing identifies:

• R0589402 – Model 200
• R0589403 – Model 260
• R0589405 – Model 400
• R0746905 – Model 400 CuNi

Jandy JXiQ

Jandy's current JXiQ service manual also identifies R0589405 as the heat exchange assembly for the standard Model 400.

Important: Standard Copper vs. Cupronickel

DO NOT ORDER BY BTU RATING ALONE

Jandy offers different 400K heat exchangers depending on the heater configuration.

R0589405

Standard Model 400 Heat Exchanger

R0746905

400K Cupronickel Heat Exchanger

Jandy specifically identifies JXiQ400NN and JXiQ400PN as models equipped with a cupronickel heat exchanger. Those configurations use R0746905, not R0589405.

Before ordering, verify the complete heater model number.

400K vs. 260K vs. 200K

These heat exchangers are different sizes and are not interchangeable.

Jandy confirms this part-number breakdown in its current heater parts documentation.

Heat Exchanger vs. Complete Combustion Chamber Assembly

The R0589405 is the heat exchange assembly, not the complete combustion chamber/header package.

Jandy separately lists complete combustion chamber and header assemblies for applicable heater configurations.

If damage extends beyond the exchanger itself to the header, combustion chamber, refractory, or other heater components, additional parts may be required.

Before ordering a major heater component, inspect the complete assembly to determine the source and extent of the failure.

Common Signs of Heat Exchanger Failure

A heat exchanger may need replacement if you notice:

• Water leaking from inside the heater cabinet
• Visible copper corrosion
• Green or blue corrosion deposits
• Scale accumulation
• Reduced heater performance
• Restricted water flow
• Frequent heater cycling
• Water underneath the heater
• Internal tube deterioration

A leaking exchanger should be diagnosed promptly because continued operation can damage additional components.

Water Chemistry Is Critical

Improper water chemistry is one of the most common causes of premature heat-exchanger damage.

Conditions that can shorten exchanger life include:

• Low pH
• Excessively high chlorine levels
• Improper total alkalinity
• Scale-forming water
• Chemical feeders installed incorrectly
• Concentrated chemicals passing directly through the heater
• Poor circulation
• Improper salt or dissolved-solids levels

Correct any underlying water-chemistry or hydraulic issue before operating the heater with a new exchanger.

Installation Guidance

Replacing the heat exchanger requires significant disassembly of a gas-fired pool heater.

Installation involves:

• Gas-fired combustion equipment
• Water plumbing
• Electrical components
• High-temperature surfaces
• Combustion chamber components
• Gaskets and seals

Installation should be performed by a qualified pool-heater technician or licensed professional familiar with Jandy equipment.

After installation, the heater should be checked for:

• Water leaks
• Proper water flow
• Correct combustion
• Gas leaks
• Venting
• Safety-control operation
• Proper heater cycling

Frequently Asked Questions

What heaters does Jandy R0589405 fit?
It is designed for compatible 400K Jandy JXi and JXiQ gas-fired pool and spa heaters.

Is this for a 400,000 BTU heater?
Yes. Jandy identifies R0589405 specifically as the Model 400 heat exchanger.

Will it fit a JXi 260 heater?
No. The standard 260K exchanger is R0589403.

Will it fit a JXi 200 heater?
No. The standard 200K exchanger is R0589402.

Is R0589405 the cupronickel exchanger?
No. Jandy lists R0746905 as the 400K cupronickel replacement.

Does it work with JXiQ heaters?
Yes. Jandy's current JXiQ manual lists R0589405 for the standard Model 400 heat exchange assembly.

Does gas type matter?
The heat exchanger is used on compatible 400K configurations; however, always verify the complete heater model before ordering.

Why Buy From Pool Supply Depot?

Pool Supply Depot supplies genuine Jandy heaters, heat exchangers, headers, burners, automation systems, pumps, filters, lighting, salt systems, and OEM replacement parts nationwide.

Because Jandy offers different heat exchangers for 200K, 260K, 400K, and 400K cupronickel heaters, we recommend verifying your complete heater model before ordering.

Send us the heater model and serial number if you're uncertain, and our team can help confirm the correct replacement.

Order the Jandy Pro Series JXi/JXiQ 400K Heat Exchanger Tube Assembly | R0589405 from Pool Supply Depot today.