A larger pool or a pool-and-spa combination that needs fast heat-up in any weather.
★★★★★ 230+ Google Reviews · CPO C-105377 · 40+ years of combined founder experience
Sizing comes first.The right heater is set by your pool's surface area and the temperature rise you want, and by the flow your pump and plumbing deliver. Start with the heater size calculator; we confirm it on site before quoting.
Our own score for what saves you money and headaches in South Florida.
JXiQ400NK
3.7
out of 5
From the manufacturer's documents listed under Sources. Where the documents disagree, the table says so.
| Manufacturer model number | JXIQ400NK (JXIQ400PK is the propane version) |
|---|---|
| BTU input (firing rate) | 399,000 BTU/hr |
| Thermal efficiency | 84% (Jandy EnergyGuide label) |
| Heat exchanger | Copper fin tube with polymer headers, factory sacrificial anode, VersaFlo integrated bypass |
| Weight | 126 lbs |
| Water connections | 2" PVC/CPVC unthreaded, or Jandy threaded union |
| Water flow | 30 GPM minimum, 100 GPM maximum |
| Working water pressure | 50 psi maximum (standard header); switch factory set to 7 psi |
| Gas connection | 3/4" NPT |
| Inlet gas supply pressure | 4.0" W.C. minimum; 10.5" W.C. maximum natural gas, 14.0" W.C. propane |
| Electrical | 120 VAC at under 5 A, or 240 VAC at under 2.5 A, auto-sensing |
| Exhaust vent | 8" diameter Category I, 4" Category III |
| Minimum outdoor ambient | 40°F |
| Cabinet | 22.1" W x 21.6" D x 26.5" H |
| Onboard sensors | Flue temperature, inlet and outlet water temperature (temperature-rise monitoring), onboard air temperature, low gas pressure, air pressure, dual high-limit switches at 135°F and 150°F |
| Controls and automation | 80-character digital display with heat-up time estimate; Bluetooth service diagnostics via the Fluidra Pro app; RS-485 to Jandy AquaLink; iAquaLink app control requires a Jandy AquaLink system. |
Parts
1 year
Labor
None published
Heat exchanger
5 years
| Parts | 1 year |
|---|---|
| Heat exchanger | 5 years (VersaFlo factory-installed) |
These are the manufacturer's published terms. Terms can depend on the installer, the dealer program and where the heater was bought, and they change without notice, so we confirm the exact term for your install on the written quote.
The traditional material and the cheapest to build. It transfers heat well and does fine on well-balanced chlorine water, but it's the least forgiving of low pH, high chlorine and salt. Water chemistry has to stay in range for a copper exchanger to reach its full life.
See every material side by side on the comparison page, or read the Jandy heater error messages guide for what the display is telling you.
Most to least forgiving of salt and unbalanced water.
Raypak · AVIA HD with NiTek
A larger pool or a pool-and-spa combination that needs fast heat-up in any weather.
Built-in Wi-Fi
Hayward · Universal H-Series
A larger pool or a pool-and-spa combination that needs fast heat-up in any weather.
App control through automation
Pentair · ETi
A high-use pool or pool-and-spa where fuel cost decides it, and a pad that can handle a condensing heater's condensate drain.
Automation relay (no heater app)
Every figure on this page comes from these manufacturer documents. We re-open each one and match the model number, capacity and efficiency before the date moves. How we verify.
| Document | Type | Last checked |
|---|---|---|
| Jandy — JXiQ Gas Pool & Spa Heater brochure, 61359_SL (part numbers, thermal efficiency, weights, vent sizes, VersaFlo, 5-year heat-exchanger warranty, iAquaLink)cdn.fluidrausa.com | Warranty terms | October 14, 2026 |
| Jandy — JXiQ Gas-Fired Pool and Spa Heater Installation & Operation Manual, H0780200 (sensor list, sacrificial anode, gas pressure, flow, RS-485 and Bluetooth)cdn.fluidrausa.com | Manual or guide | October 14, 2026 |
| Jandy / Fluidra — 2024 Product Catalog Addendum, Gas Heaters, 61356_SA (model-number key, firing rates, vent diameters, cabinet dimensions, current part numbers and Jandy's EnergyGuide thermal-efficiency labels)cdn.fluidrausa.com | Manual or guide | October 14, 2026 |
| Jandy — USA & Canada Jandy Limited Warranty, H0333803 (1 year on JXi heaters, 5 years on factory VersaFlo heat exchangers, 2 years on heat pumps with 5 years compressor and exchanger, no labor, e-commerce exclusion)cdn.fluidrausa.com | Warranty terms | October 14, 2026 |
Manufacturers revise terms without notice. Treat this page as a starting point and confirm the current terms before you buy. If something here is out of date, tell us and we'll fix it.
Parts: 1 year. Heat exchanger: 5 years (VersaFlo factory-installed). These are the manufacturer's terms as published; warranty terms change and can depend on the installer and the channel, so we confirm the exact term for your install on the written quote.
The JXiQ400NK is rated at 399,000 BTU/hr input. Heater size comes from your pool's surface area and the temperature rise you want, not from gallons, and the pump and plumbing have to deliver the flow the heater needs. Use our heater size calculator for a starting number, and we confirm it on site before quoting.
Only through a compatible automation system. The JXiQ400NK has no Wi-Fi of its own, so the app control comes from the automation system it's wired to.
The traditional material and the cheapest to build. It transfers heat well and does fine on well-balanced chlorine water, but it's the least forgiving of low pH, high chlorine and salt. Water chemistry has to stay in range for a copper exchanger to reach its full life.
Every figure on this page comes from the manufacturer's own documents, listed under Sources with the date we last checked them. Manufacturers revise terms without notice, so treat the page as a starting point and confirm the current terms on your quote.
We quote, install and service Jandy heaters across Palm Beach and Broward, managed by us under our Florida Certified Pool/Spa Contractor license (CPC1461731). You get a free on-site sizing visit and one written price. Gas lines, new circuits and refrigerant work are done by licensed contractors we manage.
We call back within 30 minutes during business hours.
