Product Overview

The Jandy R0303805 Complete Heat Exchanger Assembly is a genuine OEM replacement designed specifically for Jandy Hi-E2® Model 350 pool and spa heaters.

This complete copper heat exchanger assembly transfers heat generated by the heater into the circulating pool or spa water. It is designed as a factory replacement for a leaking, corroded, damaged, or failed original heat exchanger in compatible Hi-E2 350 heaters.

For commercial facilities, hotels, aquatic centers, residential pools, and other demanding applications using a Jandy Hi-E2 350 heater, replacing a damaged heat exchanger with the correct OEM assembly helps restore proper heater performance and reliability.

Key Features

• Genuine Jandy / Zodiac OEM replacement part
• Manufacturer Part Number: R0303805
• Complete heat exchanger assembly
• Designed specifically for Jandy Hi-E2 Model 350 heaters
• Copper heat exchanger construction
• Factory-style replacement for the original heat exchanger
• Designed for pool and spa heating applications
• Suitable for residential and commercial Hi-E2 installations
• Professional installation strongly recommended

Compatibility

The Jandy R0303805 is designed for:

• Jandy Hi-E2® Model 350 Pool Heater
• Jandy Hi-E2® 350 Pool & Spa Heater
• Compatible 350-size Hi-E2 heater configurations using the factory copper heat exchanger

Specifications

Copper vs. Cupronickel

It is important to verify which heat exchanger material is required before ordering.

• R0303805 – Complete Copper Heat Exchanger Assembly for Hi-E2 350
• R0523705 – Complete Cupronickel Heat Exchanger Assembly for Hi-E2 350

These parts should not be confused with one another. Verify the original heater configuration and heat exchanger material before replacement.

When Should a Heat Exchanger Be Replaced?

Common signs of a failing Hi-E2 heat exchanger can include:

• Water leaking from inside the heater
• Visible corrosion
• Cracked or damaged tubing
• Reduced heating performance
• Water entering areas of the combustion chamber
• Repeated header or exchanger leakage
• Significant mineral buildup or internal deterioration

Before replacing the heat exchanger, the underlying cause of failure should be identified.

Improper pool water chemistry, excessive chlorination, low pH, inadequate water flow, scaling, or improper heater operation can shorten heat exchanger life.

Complete Assembly vs. Tube Assembly

The R0303805 is the complete heat exchanger assembly, rather than only the replacement tube bundle.

For reference:

• R0303805 – Complete Copper Heat Exchanger Assembly
• 10839405 – Copper Heat Exchanger Tube Assembly
• R0303900 – Inlet/Outlet Header
• R0304000 – Return Header
• R0304300 – Header Gasket
• R0304400 – Bypass Valve Assembly

Choosing the complete assembly can be beneficial when multiple components of the existing heat exchanger system are deteriorated or damaged.

Installation Information

Replacing a heat exchanger requires substantial disassembly of the heater and should be performed by a qualified pool-heater technician.

Prior to installation, verify:

• Heater model is Hi-E2 350
• Existing exchanger is the copper configuration
• Plumbing flow is within manufacturer specifications
• Pool and spa water chemistry is properly balanced
• Heater bypass components are operating correctly
• Header connections and plumbing are properly aligned
• The original heat exchanger failure has been diagnosed

Correct installation and balanced water chemistry are critical to maximizing the life of the replacement heat exchanger.

Frequently Asked Questions

Does R0303805 fit the Jandy Hi-E2 350?

Yes. R0303805 is the OEM complete copper heat exchanger assembly specified for the Jandy Hi-E2 Model 350 heater.

Is R0303805 copper or cupronickel?

R0303805 is the copper version.

The cupronickel heat exchanger assembly for the Hi-E2 350 is R0523705.

Is this the complete heat exchanger?

Yes. R0303805 is identified as the complete heat exchanger assembly, not simply the copper tube bundle.

What is the tube-only assembly?

The copper heat exchanger tube assembly for the Hi-E2 350 is 10839405.

Can this be installed on a different Hi-E2 heater size?

This part is specifically identified for the 350-size Hi-E2 heater. Always verify the heater model and serial information before ordering.

Should a professional install this part?

Yes. Heat exchanger replacement involves the heater's water, combustion, and safety systems. Installation by a qualified pool-heater technician is strongly recommended.