Pentair MasterTemp 250 NG Gas Pool Heater
An average-sized Florida pool with no spa, or a pool where gas is the backup to solar or a heat pump rather than the everyday heat source.
Gas heater
SKU MasterTemp 250 NG
- BTU input
- 250,000 BTU/hr
- Fuel / power
- Natural gas
- Thermal efficiency
- 84% thermal efficiency (input rated; 250,000 BTU/hr input)
- Heat exchanger
- Copper
- Warranty
- Parts: 2 years · Labor: 2 years
- Controls & automation
- Two-line LCD with separate pool and spa setpoints, fault history for the last five errors, runtime, cycles, stack flue temperature and flame status; RS-485 COM port for direct IntelliCenter control, 2-wire fireman's switch for IntelliTouch, EasyTouch, IntelliConnect or a time clock.
Modern Pool Heating Equipment Score
Our score for the equipment itself. It is not a Google or customer review rating.
How we rate heatersFull specifications
Every row below is taken from a manufacturer document. Anything the manufacturer does not publish is left out rather than estimated.
| Manufacturer model | MasterTemp 250, natural gas, P/N 460732 |
|---|---|
| BTU input | 250,000 BTU/hr input — Pentair defines MasterTemp model size as BTU input in thousands of BTU/hr |
| Thermal efficiency | 84% (tested per ANSI Z21.56:19/CSA 4.7:19 2019, section 5.10) |
| Heat exchanger | Copper (the 250HD, P/N 460806, uses cupro-nickel) |
| Fuel | Natural gas (P/N 460733 is the propane version) |
| Emissions | Certified for low NOx emissions; CSA certified to CSA/ANSI Z21.56:19/CSA 4.7:19 |
| Water connections | 2" PVC slip unions, supplied with the heater |
| Water flow | 25 GPM minimum, 120 GPM maximum (bypass valve required above 120 GPM) |
| Gas connection and supply pressure | 3/4" pipe to the gas valve; 4" w.c. minimum and 14" w.c. maximum inlet; manifold factory set at -0.2" ±0.1" w.c.; sediment trap and manual shut-off required outside the cabinet |
| Gas pipe sizing (natural gas) | 3/4" to 20 equivalent ft, 1" to 70 ft, 1-1/4" to 250 ft (add 3 ft per elbow) |
| Electrical | 120 or 240 VAC, 60 Hz, single phase; 15 A circuit, 14 gauge field wiring; about 5 A at 120 VAC or 2.5 A at 240 VAC. Ships with the 240 VAC plug fitted. Not rated for 208 VAC. |
| Clearances | 6" from combustible surfaces on the top, exhaust side, header side and door panels; 3 ft between the top of the exhaust vent and any roof overhang; 36" from an air conditioner or heat pump |
| Dimensions and weight | 23.02" W x 21.0" D x 28.15" H; 133 lb carton weight |
| Minimum water temperature | Do not run continuously below 68°F water — condensation damage voids the warranty |
| Controls and automation | RS-485 COM port connects directly to an IntelliCenter Control System (up to 16 heaters, addresses 1-16; the heater's own buttons go inactive and its alarms appear on the IntelliCenter home screen). IntelliTouch and EasyTouch use the 2-wire fireman's switch terminals; Pentair's IntelliConnect guide wires a heater through its low-voltage dry contacts to the heater's external switch connection. Optional Smart Heater Bypass Kit P/N 462048. |
| Florida anchoring | Bolt Down Bracket Kit P/N 460738; Pentair states anchor clamps are required in Florida |
Why homeowners consider it
- Same 84% thermal efficiency as the 400, same LCD, same RS-485 automation port and same cabinet — you are buying less capacity, not a cheaper design.
- The smaller input makes the gas line far easier to live with. Pentair's table allows 3/4 inch pipe to 20 equivalent feet on natural gas and 1 inch to 70 feet, where the 400 needs 1 inch just to reach 20 feet.
- 40 GPM is a lot of water to push through a heater on a variable-speed pump. The 250 needs only 25 GPM minimum, which usually means a lower, quieter, cheaper heating speed.
- It is a genuinely good match as a backup heater behind solar or a heat pump: enough to cover a cold front or a weekend of guests, without the fuel bill or the gas-line work of a 400.
- Parts, boards, igniters and sensors are the same family used across the MasterTemp line, so availability in Florida is excellent.
What to know before buying
- It is not a spa heater in any hurry. If you have an attached spa you want hot in half an hour, size up — the 400 exists for that job.
- The exchanger is copper. On a salt pool or a coastal lot, the MasterTemp 250HD (P/N 460806) with a cupro-nickel exchanger is the better answer at 82% efficiency.
- Natural gas has to be at the street. The propane version is P/N 460733, and propane means a tank, a delivery contract and a higher cost per degree.
- Flow window is 25 GPM minimum to 120 GPM maximum. Above 120 GPM a bypass valve has to be fitted and locked.
- Pentair warns against running the heater continuously below 68°F water temperature — it causes condensation damage and voids the warranty.
- Warranty is 2 years parts and labor through the professional channel only; an internet purchase drops it to 1 year parts with no labor.
Warranty, term by term
The warranty only matters on the parts that actually fail. Here is how this one splits up.
- Parts
- 2 years
- Labor
- 2 years
Pentair's published warranty table gives MasterTemp 2 years parts and labor when the heater is bought through a brick-and-mortar retailer, pool builder or pool service company AND installed by a qualified professional who charges a fee. A heater bought from an internet retailer is covered for 1 year parts only, with no labor. Pentair also publishes a bundle: install a qualifying pump, filter and heater together and all three go to 3 years. Registration is required. MasterTemp is a TradeGrade product, which is Pentair's professional-channel line. Professional installation and authorized-channel requirements apply.
Why the heat exchanger matters
The heat exchanger is the part of a pool heater that actually moves heat into the water, and what it is made of decides how long the heater survives Florida water chemistry. Here is what the four materials mean in practice.
- CopperThis heater
- The traditional material and the cheapest to build. It transfers heat well and is fine on a well-balanced chlorine pool, but it is the least forgiving of low pH, high chlorine and salt. On the Gulf Coast it is usually the first component to fail.
- Cupro-nickel
- Copper alloyed with nickel. It gives up a little heat transfer in exchange for much better resistance to unbalanced water chemistry and salt. On gas heaters this is the upgrade worth having in Florida, and some manufacturers now ship it as standard.
- NiTek (nickel alloy)
- A nickel-alloy exchanger used on some gas heaters as a corrosion-resistant alternative to copper. Positioned between cupro-nickel and titanium in both durability and price.
- Titanium
- Effectively immune to pool water chemistry, including salt. It is the standard on quality pool heat pumps and the reason a heat pump can sit on a salt pool for years without exchanger trouble. It is expensive, which is why you rarely see it on gas heaters.
Whatever the material, plumbing order matters just as much: a chlorinator or salt cell belongs downstream of the heater, never upstream.
How we scored it
- Warranty is identical to the rest of the MasterTemp line: 2 years parts and labor through the professional channel, 1 year parts only online.
- Copper exchanger is the category baseline. On a salt pool we would point you at the 250HD instead, which is exactly why this SKU sits at 3.5 rather than 4.5.
- Efficiency matches the 400 at 84%, but capacity is half a point behind on the performance criterion because 250,000 BTU/hr recovers a pool slowly and will not serve an attached spa well.
- Serviceability is the strongest score: the same boards, igniters and sensors as every other MasterTemp, stocked everywhere in Florida.
- Controls are identical to the 400 — RS-485 straight into IntelliCenter, fireman's switch for everything else — which is best-in-class among gas heaters.
- Value is strong at this size, particularly as a backup heater behind solar or a heat pump, where the lower gas-line and flow requirements save real money at installation.
- The computed score lands below the owner's 4.5 starter score for the MasterTemp line. That starter score covers the whole family including the larger and the cupro-nickel HD models; this is the smallest copper SKU we publish, and the exchanger material plus the modest capacity are what pull it down.
Real Modern Pool Heating installations
Installed locally, researched for everyone
Affordable Solar & Pool Heating, LLC installs and services pool heating in Sarasota, Manatee, Charlotte & Pinellas County, Florida. If you are outside that area this page is still yours to use — take the questions on it to your local contractor. Pool heater installation in Sarasota.
Other heaters worth putting beside it
Same job, different tradeoffs. Every one of these has its own verified spec page.
Hayward · Universal H-Series
Hayward Universal H-Series H250FDN Gas Pool Heater
Model H250FDN
- BTU input
- 250,000 BTU/hr
- Thermal efficiency
- 84%
- Heat exchanger
- Cupro-nickel
- Warranty
- 3-Year Parts / 1-Year Labor
- Wi-Fi / automation
- App Control via AutomationAutomation Compatible (Relay)
An average-sized Florida pool, or a pool with a small spa, where you want gas-speed heat without paying for 400,000 BTU you will never use.
Pentair · MasterTemp HD
Pentair MasterTemp 250HD Heavy Duty Gas Pool Heater
Model MasterTemp 250HD
- BTU input
- 250,000 BTU/hr
- Thermal efficiency
- 82%
- Heat exchanger
- Cupro-nickel
- Warranty
- 2-Year Parts & Labor
- Wi-Fi / automation
- Automation Compatible
An average-sized salt-water or coastal pool that wants a corrosion-resistant exchanger without the gas line, flow rate and fuel bill of a 400,000 BTU heater.
Pentair · MasterTemp
Pentair MasterTemp 400 NG Gas Pool Heater
Model MasterTemp 400 NG
- BTU input
- 400,000 BTU/hr
- Thermal efficiency
- 84%
- Heat exchanger
- Copper
- Warranty
- 2-Year Parts & Labor
- Wi-Fi / automation
- Automation Compatible
A large pool, or a pool and spa combination, on a pad that is already Pentair and an owner who wants heat on demand rather than an everyday running cost.
MasterTemp 250 NG questions
Is a 250,000 BTU heater big enough for my pool?
For an average residential pool with no attached spa, usually yes — especially if you are holding a temperature rather than chasing one. For a large pool, a pool you want warm on demand, or any pool with a spa, go up to the 400. We size it against surface area, exposure and how you actually use the pool rather than from gallons alone.
What is the difference between the MasterTemp 250 and the 250HD?
The exchanger. The 250 (P/N 460732) uses copper at 84% thermal efficiency; the 250HD (P/N 460806) uses cupro-nickel at 82%. Pentair positions the HD for low pH, high flow and heavy use. The HD is natural gas only.
Can I run it on propane?
Not this SKU. P/N 460732 is the natural gas heater; P/N 460733 is the propane version of the same model. Do not attempt to convert a heater between fuels — Pentair's manual is explicit about that.
Will it hold temperature through a Florida winter?
Yes, but the running cost is the question, not the capability. Gas heats regardless of weather, which is its advantage; it is also the most expensive fuel per degree. Owners who run a gas heater as an everyday November-to-March pool heater are the ones who end up calling us about a heat pump.
Does it work with a variable-speed pump?
Yes, as long as the heating speed is programmed above 25 GPM through the heater. Below that the water pressure switch will not close and the heater will report insufficient flow. It is worth setting a dedicated heating speed rather than trying to heat on the filtration speed.
Do you install this heater locally?
Yes. We install and service Pentair gas heaters throughout Sarasota, Manatee, Charlotte & Pinellas County, Florida. The comparison content here is written for pool owners anywhere; the installation offer is local.
Is the MasterTemp 250 NG right for your pool?
We install and service pool heating in Sarasota, Manatee, Charlotte & Pinellas County, Florida. If you are outside that area, the comparison above is still yours to use — ask your local contractor the same questions.
Licensed & insured · Florida Certified Pool/Spa Contractor #CPC1460367 · Mon-Sat, 8am-6pm
Last verified September 17, 2026
Specifications and warranty terms are taken from the manufacturer documents below. Manufacturers revise these without notice, so confirm the current terms before you buy. If you spot something out of date, email us and we will fix it.
Sources
- Pentair — MasterTemp High Performance Heater product page (models, part numbers, efficiency)
- Pentair — MasterTemp 250 natural gas SKU page (P/N 460732)
- Pentair — MasterTemp Pool and Spa Heater Installation and User's Guide (BTU input, gas pressure, flow, clearances, electrical, error codes)
- Pentair — 2025-2026 Pool Product Catalog, Heaters & Heat Pumps section (June 2025)
- Pentair — High-Performance Pool & Spa Gas Heaters brochure (efficiency, exchanger, dimensions, heat-up times)
- Pentair — Pool product warranty information (parts, labor, compressor, exchanger terms and channel conditions)
- Pentair — IntelliConnect Control and Monitoring System Installation Guide (how a heater is wired to IntelliConnect)
Ratings on this site are the editorial opinion of Affordable Solar & Pool Heating, LLC, trading as Modern Pool Heating. How we rate heaters. Corrections: modernpoolheating@icloud.com.
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Mon-Sat, 8am-6pm · Licensed & insured · Florida Certified Pool/Spa Contractor CPC1460367