Product Information
Description
Hayward FDXLHXA1350 Heat Exchanger Assembly, H350FD Universal H-Series
Bring the H350FD back to full fire.
The Hayward FDXLHXA1350 Heat Exchanger Assembly (PST-FDXLHXA1350) is the genuine OEM replacement bundle for the H350FD Universal H-Series Low NOx pool and spa heater, complete with the cupro-nickel finned tube, header end caps, gaskets, and hardware needed to put a 350,000 BTU heater back into service. It bolts into the existing cabinet using the original 2 in x 2.5 in CPVC union connections, so your manifold, gas train, and electrical do not need to move. If your H350FD is leaking from a corroded tube, ghosting heat to the cabinet, or throwing flow faults from a clogged exchanger, this is the part that restores it.
Genuine Cupro-Nickel Core
You get Hayward's cupro-nickel finned tube assembly, the same heat exchanger the H350FD shipped with from the factory. Cupro-nickel resists the pitting, etching, and stress cracking that kill copper exchangers in salt pools, high-flow systems, and water that drifts low on pH or high on chlorine. This is the upgrade material across the Universal H-Series line, and it is what keeps the next exchanger from failing the same way the last one did.
Drop-In for the H350FD Cabinet
The FDXLHXA1350 is sized exactly to the H350FD forced-draft cabinet, with the correct header height, tube length, and burner tray clearance. You reuse your existing 2 in by 2.5 in CPVC unions, gas valve, blower, and ignition control, so a swap is a header-side job, not a full re-plumb. If your rating plate shows an FD in the model number and a 350K BTU input, this is the matched assembly.
Built for Salt and Aggressive Water
Hayward's Totally Managed Flow design moves water evenly across every tube, so you do not get hot spots and stagnant zones that eat through copper. Pair that with the cupro-nickel alloy and you have an exchanger that holds up to salt chlorine generators, mineral systems, and the high-velocity flow that comes off variable-speed pumps. It is the right exchanger for any H350FD that runs on a salt cell or sees frequent shock dosing.
Who It's For
H350FDN Natural Gas Heaters
Replaces the original exchanger in the H350FDN natural gas variant of the Universal H-Series Low NOx 350K heater.
H350FDP Propane Heaters
Same assembly used in the H350FDP propane variant. The exchanger is shared across both fuel types in the H350FD family.
Salt Pool Systems
The cupro-nickel core is the recommended exchanger for pools running a salt chlorine generator, where copper exchangers see accelerated wear.
Residential and Light Commercial
Restores both residential H350FD installs and the light-commercial spa and small commercial pool applications the H-Series is rated for.
Why PST Customers Pick This
Restores Full 350K BTU
A leaking or scaled exchanger drops heat output and burner efficiency. Fresh tubes give the H350FD its full 350,000 BTU/hr rating back.
Salt-Compatible Alloy
Cupro-nickel holds up to the chloride exposure that comes off salt chlorine generators, so the next exchanger lasts in salt pools.
Totally Managed Flow
Engineered flow paths spread water evenly across every tube, preventing hot spots and the pinhole leaks they cause.
Reuses Existing Unions
The 2 in by 2.5 in CPVC unions, gas train, and electrical stay put. The swap happens at the header and tube bundle.
Genuine Hayward OEM
Built to the original FDXL spec, so warranty coverage and parts compatibility on the heater are preserved.
Complete Assembly
Ships as the matched tube and header assembly Hayward specifies for the H350FD, not a bare-tube kit.
Professional Installation Required
This is a gas-fired heat exchanger repair on a sealed combustion appliance. Gas connections, venting, and combustion setup must be handled by a licensed gas technician per NFPA 54 and the Hayward H-Series installation manual. Electrical bonding must follow NEC Article 680. Improper reassembly can produce carbon monoxide, gas leaks, or scalding water temperatures. Hayward requires proof of installation by a certified technician to validate the heat exchanger factory warranty.
Full Specifications
Frequently Asked Questions
How do I know if the FDXLHXA1350 fits my heater?
Check the rating plate on the side of your Hayward heater. You need a model number that contains H350FD, an FD (forced draft) designation, and a 350,000 BTU/hr input rating. Both H350FDN (natural gas) and H350FDP (propane) use this same exchanger assembly. If your heater is 250K or 400K, or shows IDL or ASME on the plate, this is the wrong part.
What is the difference between the FDXLHXA1350 and the FDXLHXA1250 or FDXLHXA1400?
The last three digits track the BTU size of the heater they fit. The FDXLHXA1250 fits the 250K BTU H250FD, the FDXLHXA1350 fits the 350K BTU H350FD, and the FDXLHXA1400 fits the 400K BTU H400FD. They share the same family design but are sized to different cabinets and tube counts. Order by your heater's BTU rating, not by what looks close.
Do I need a different exchanger for a salt pool?
No, this is the right exchanger for a salt pool. The FDXLHXA1350 uses cupro-nickel, which is the alloy Hayward recommends for any pool running a salt chlorine generator. Copper exchangers on older non-FD heaters wear out fast in salt systems, but cupro-nickel holds up to chloride exposure and is the standard build for the H-Series.
What does the kit include?
You get the complete heat exchanger assembly with the cupro-nickel finned tube bundle, header end caps, and gaskets needed to seat the assembly in the H350FD cabinet. Burners, the burner tray, gas valve, ignition module, blower, and outer cabinet are not included, you reuse those from your existing heater.
Can I install this myself?
No, and Hayward does not allow it. The H350FD is a gas-fired forced-draft heater with sealed combustion, and the exchanger swap requires breaking the gas connection, opening the combustion chamber, and re-pressure-testing the gas train per NFPA 54. Hayward requires the work to be done by a licensed gas technician, and the factory exchanger warranty is voided without proof of professional installation. Bonding must also be verified per NEC Article 680.
What usually causes the original exchanger to fail?
The top three causes are chronic low pH that etches tube walls, low flow from a clogged filter or undersized pump that overheats the exchanger, and off-season freeze damage when water is left in the heater. Replacing the exchanger without fixing the underlying water chemistry, flow rate, or winterization habit usually leads to the same failure on the new part within a season or two.
Is this a genuine Hayward part?
Yes. PST is an authorized Hayward dealer and the FDXLHXA1350 ships as a genuine Hayward OEM assembly with full warranty coverage when installed by a licensed technician. Aftermarket copies exist but typically use thinner copper or non-spec gaskets and will void your H-Series warranty.
Order the FDXLHXA1350 From PST
Authorized Hayward dealer. Get the genuine OEM heat exchanger for your H350FD, backed by PST's service team if you need help confirming the right part before your technician shows up.
Additional Info
| Category | Parts Pool Parts Pool Heater Parts |
| SKU | PST-FDXLHXA1350 |
| MPN | FDXLHXA1350 |
| Manufacturer | Hayward |
| Weight | 48.5 lb |
Let customers speak for us
Easy to order - received the next day!
Beautiful!!
The valve fit perfectly and works great.
Fast shipping and great price!
Does what a small weed- eater would do it minutes versus an hour
Great product does exactly what was advertised to do.
I ordered the wrong part. Customer service was very helpful. I returned it and within the week my credit card was credited back. Excellent customer service policy.
There was a delay in shipping due to postal service. They sent another part right away.
New model 59303 works great, but too bad the last generation Balboa WiFi module 50350 became un-useable.
Exactly as advertised and super fast shipping and delivery
