Quick answer: A pool heater’s high-limit switch is the safety cutoff that shuts down the burner or compressor if water inside the heat exchanger gets too hot — most gas heaters trip it around 135°F. For Raypak Digital/AVIA heaters the auto-reset switch is OEM part 006725F (roughly $52-$77); Pentair MasterTemp and Max-E-Therm use 42001-0063S (roughly $60-$85); Hayward Universal H-Series uses the FDXLHLI1930 wire-harness kit (roughly $80-$87); and Zodiac/Jandy JXi heaters use a dual-sensor kit, part R0592300 (roughly $89-$108), which trips its first-pass sensor at 135°F and its outlet sensor at 150°F. Before you buy any of these: pool-repair troubleshooting sources are consistent that a tripping high-limit switch is most often caused by restricted water flow or exchanger scale, not a bad switch — see the honesty-hook section below before you replace a part that may not be the actual problem.
Pool heater high-limit switches at a glance
| High-limit switch | Fits | Trip point | Price |
|---|---|---|---|
| Raypak 006725F | Digital/AVIA R185A-R405A, 207A-407A | 135°F, auto-reset | $52-$77 |
| Pentair 42001-0063S | MasterTemp 125-400 / Max-E-Therm | 135°F | $60-$85 |
| Hayward FDXLHLI1930 | Universal H150FD-H500FD, H150FDN/FDP-H400FDN/FDP | 135°F | $80-$87 (kit) |
| Zodiac/Jandy R0592300 | JXi 200/260/400 | 135°F first-pass, 150°F outlet | $89-$108 |
1. Raypak 006725F — For Raypak Digital and AVIA Heaters
Raypak 006725F High-Limit Switch (auto-reset, 135°F)
- The OEM auto-reset high-limit switch for Raypak's Digital and AVIA lines, the same heaters covered in our best Raypak pool heater roundup.
- Raypak's own fault-code documentation shows most Digital/AVIA units actually run two physical high-limits — a manual-reset primary switch plus this auto-reset secondary — but 006725F (cross-referenced as 600892B at some suppliers) is the one we could confirm a current retail part number and price for.
- Cross-check your model's exact fault code against Raypak's own documentation before ordering, since the manual-reset primary switch on this line uses a different part number.
- A pure electrical swap — two spade connectors and a mounting screw, no gas-line work.
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2. Pentair 42001-0063S — For MasterTemp and Max-E-Therm
Pentair 42001-0063S High-Limit Switch (135°F trip)
- The OEM high-limit switch for Pentair's MasterTemp and Max-E-Therm lines, the same heaters reviewed in our Hayward vs Pentair comparison.
- Single-switch design (unlike Raypak's dual-limit setup or Jandy's dual-sensor kit below), trips at 135°F.
- Pricing runs $60-$85 across retailers, with sale pricing at some suppliers pushing the floor down — worth comparing a couple listings before ordering.
- Confirm your exact MasterTemp or Max-E-Therm model number before ordering; the switch mount varies slightly across the model range.
3. Hayward FDXLHLI1930 — For Universal H-Series
Hayward FDXLHLI1930 High-Limit Wire Harness Kit
- The OEM high-limit kit for Hayward's Universal H-Series and Low NOx lines, spanning the H150FD through H500FD models.
- Sold as a wire-harness kit rather than a bare switch — we could only confirm a retail price for the full kit, not a standalone switch, so budget for the kit price above.
- 135°F trip point, single-switch design like Pentair's, rather than Raypak's dual-limit or Jandy's dual-sensor setup.
- Same electrical-only swap as the other brands here — no gas line involved, power off at the breaker before starting.
4. Zodiac/Jandy R0592300 — For JXi Heaters
Zodiac/Jandy R0592300 Dual-Sensor High-Limit Kit
- The OEM high-limit kit for Zodiac/Jandy's JXi line — the only one of the four brands here that uses a genuine dual-sensor design rather than a single switch: a first-pass sensor trips at 135°F, and a second sensor at the outlet trips at 150°F as a backup.
- Watch for a naming trap: part R0457400 is commonly listed online as a "Jandy high-limit switch," but it's actually built for the older Legacy LRZE and LXi lines, not JXi. Confirm R0592300 specifically if you own a JXi heater.
- Priced in stock at $89-$108 across the retailers we checked — this is the priciest of the four parts here, since it's a dual-sensor kit rather than a single switch.
Before you replace it — check flow and scale first
A tripping high-limit switch feels like a switch problem, but pool-repair troubleshooting sources are consistent that it’s usually a symptom of something else trapping heat in the exchanger rather than a failed part. The two most common causes are restricted water flow — a dirty filter, a partly closed valve, or a pump running at too low a speed — and scale or calcium buildup coating the inside of the heat exchanger, which insulates it from the cooling water flowing past it even when flow itself is fine. Our not-heating troubleshooting guide walks through the flow and airflow checks that resolve most trips without buying a new switch at all, and our maintenance guide covers the water-chemistry checks that prevent scale from building up in the first place. If you’ve already ruled both of those out and the switch is still tripping — or won’t reset at all — that’s when it’s genuinely time to replace the part itself.
The bottom line
A high-limit switch is one of the cheapest, most DIY-friendly parts on a pool heater — $52-$108 depending on brand, with a straightforward two-wire swap and no gas-line work involved. The Raypak 006725F, Pentair 42001-0063S, Hayward FDXLHLI1930, and Zodiac/Jandy R0592300 cover the four major brands, but don’t reach for any of them until you’ve ruled out low flow or exchanger scale as the real cause of the trip — replacing a working switch won’t fix an underlying flow problem. Check our parts guide for the other components worth inspecting at the same time, and our repair cost guide for what a professional diagnosis and swap runs if you’d rather not do it yourself.