Quick answer: A pool heater gas conversion kit swaps the burner orifices and resets the gas valve’s regulator so the same heater can run on natural gas instead of propane, or vice versa — useful if you’re moving a heater, adding a gas line, or buying used. For Pentair MasterTemp/Max-E-Therm heaters the kit runs roughly $52-$90 depending on model (part 461062/461063 for the MT125, 460755 for the 250); Hayward’s Universal H-Series Low NOx kit (FDXLCNK0001) lists around $254; and Raypak’s older Gemini/RP2100-series kits (004690B/004693F) show retailer prices anywhere from $133 to $382. The part is easy enough to order yourself, but manufacturers specify the actual swap — resetting gas pressure and verifying it with a manometer — be done or checked by a qualified technician, since a wrong pressure setting risks soot, short-cycling, or excess carbon monoxide.
Why you’d convert a pool heater instead of buying a new one
Most pool heaters ship in a single fuel configuration from the factory, but the burner assembly on many models is designed to accept a factory-approved kit that re-jets it for the other fuel. That matters in a few real situations: you’re installing a used heater that was set up for the previous owner’s fuel type, you’re moving a heater to a property with a different gas service, or you’re adding a natural gas line to a pad that currently only has a propane tank. A conversion kit is almost always cheaper than replacing the whole heater — the kits below run well under $400, against $2,000-$5,000+ for a new unit — but it only works if your specific heater model has a manufacturer-approved kit; not every heater supports field conversion, so check your model’s install manual before assuming one exists.
Pool heater conversion kits at a glance
| Kit | Fits | Direction | Price |
|---|---|---|---|
| Pentair 461062 / 461063 | MasterTemp / Max-E-Therm 125 | LP↔NG (both kits sold) | ~$74-$90 |
| Pentair 460755 | MasterTemp 250 | NG→LP | ~$52 |
| Hayward FDXLCNK0001 | Universal H-Series Low NOx | NG→LP | ~$254 |
| Raypak 004690B / 004693F | Gemini/RP2100 R185-R405 (legacy) | NG↔LP (both kits sold) | $133-$382 |
1. Pentair 461062 / 461063 — For MasterTemp and Max-E-Therm 125
Pentair 461062 (LP→NG) / 461063 (NG→LP) Conversion Kit
- Covers the same MasterTemp line featured in our best Pentair MasterTemp pool heater roundup — the 125K BTU model specifically.
- Sold as two separate part numbers depending on which direction you're converting; order the wrong one and it won't fit the burner tray, since orifice sizes differ by fuel.
- Retailer listings landed in a fairly tight $74-$90 band across the sources we checked, a narrower spread than the legacy Raypak kits below.
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2. Pentair 460755 — For MasterTemp 250
Pentair 460755 Natural-to-Propane Conversion Kit
- The cheapest kit we found across all three brands, likely reflecting a simpler orifice-only swap on this model rather than a full gas-valve regulator change.
- Natural-to-propane direction only in the listing we sourced — if you need to go the other way (propane to natural) on a 250K model, confirm the matching part number with a Pentair dealer before ordering.
- Same underlying MasterTemp platform Sta-Rite rebadges, so this part number carries over if you own that badge instead.
3. Hayward FDXLCNK0001 — For Universal H-Series Low NOx
Hayward FDXLCNK0001 Conversion Kit
- Covers the full H-Series Low NOx lineup featured in our best Hayward pool heater roundup, from the 150K to the 400K BTU models.
- By far the most expensive kit on this page — roughly 3-5x the Pentair kits — likely reflecting the larger burner assembly and stricter Low NOx emissions calibration these heaters run.
- One retailer's Q&A section noted the kit ships without printed installation instructions, reinforcing that this is meant to be installed by someone who already knows the procedure, not a first-timer working from the box insert.
4. Raypak 004690B / 004693F — For Legacy Gemini and RP2100 Heaters
Raypak 004690B (NG→LP) / 004693F (LP→NG) Conversion Kit
- These fit Raypak's older Gemini, Versa, and RP2100-series heaters (models built roughly 1974-2004) rather than the current Digital or AVIA lines covered in our best Raypak pool heater roundup — confirm your model number before ordering.
- The widest price spread of any kit on this page: one retailer listed $133, another $382 for the same part number. That gap is large enough to be worth shopping around rather than buying the first listing you find.
- Don't confuse this with Raypak's separate "high elevation" kits, which re-jet the heater for altitude rather than changing fuel type — they're a different product in the same parts-catalog section, and only relevant above roughly 2,000 feet.
Why this isn’t quite a solo DIY job
Ordering the kit is the easy part. Installing it means pulling the burner tray to swap orifices sized for the new fuel, then resetting the gas valve’s regulator spring or pressure tap so manifold pressure matches the new fuel’s spec — natural gas and propane run at meaningfully different pressures, and that setting has to be verified with a manometer, not eyeballed. Get it wrong and the heater can soot up, short-cycle, or in a worst case produce excess carbon monoxide. That’s why Raypak’s and Pentair’s own installation documentation specifies the conversion be performed or verified by a qualified technician, and why most manufacturer warranties require it — similar in spirit to why we don’t walk through a DIY install on our gas valve guide, even though the part itself ships to anyone who orders it.
The bottom line
A conversion kit is the cheaper path when a heater and its fuel supply don’t match — $52-$90 for most current Pentair models, ~$254 for Hayward’s Universal H-Series, and a wider $133-$382 if you’re sourcing a kit for an older Raypak Gemini or RP2100 unit. Knowing the right part number for your model mostly protects you from an inflated quote or the wrong kit landing on your doorstep; the actual pressure-setting and verification work is worth paying a technician for. If you’re troubleshooting a heater that won’t fire rather than planning a fuel switch, our not-heating troubleshooting guide covers the more common, cheaper causes to rule out first. And if a technician is already resetting manifold pressure during the conversion, that’s a good time to inspect the manifold and header gaskets too — see our manifold and header guide for OEM part numbers by brand.
Sources: InyoPools — Hayward OEM conversion kit listing, GetPoolParts — Pentair 461062 listing, Pool Supply Unlimited — Raypak conversion and high-elevation kit listings, Parts4Heating — Raypak Gemini/RP2100 parts and pricing, Pool and Spa Parts Depot — Raypak 004693F listing