Pentair MasterTemp® Natural Gas High Performance Heater 300K BTU
The Pentair MasterTemp® Natural Gas High Performance Heater 300K BTU offers all the efficiency, convenience, and reliability features you want in a pool heater — plus a lot more. As easy to use as your home heating system, with a user-friendly LCD display and troubleshoot icons that make system operation and monitoring a snap. The compact design and super-quiet operation won't intrude on your poolside leisure time.
Built by Pentair with a heavy-duty cupro-nickel heat exchanger that stands up to the harshest applications — low pH, high flow, or heavy use — the MasterTemp 300K BTU sits between the 250K and 400K in the lineup, delivering best-in-class energy efficiency. CSA certified. Backed by a 2-year warranty.
⚠️ Professional Installation Required. Pool heater installation involves gas line connections and electrical wiring. Always use a licensed contractor to ensure safety, code compliance, and warranty validity.
Key Features
300,000 BTU Output
Upper mid-range natural gas heating — between 250K and 400K in the MasterTemp lineup.
Cupro-Nickel Heat Exchanger (HD)
Heavy-duty exchanger withstands low pH, high flow, and heavy use applications.
Best-in-Class Energy Efficiency
Green certified — outperforms industry standards for efficiency.
LCD Display with Troubleshoot Icons
User-friendly display makes operation and monitoring simple.
Compact, Quiet Design
Same 23-inch wide cabinet as other MasterTemp models — quiet operation.
CSA Certified
Meets North American safety standards for gas-fired pool heaters.
Indoor and Outdoor Rated
Suitable for both indoor and outdoor pool and spa installations.
2-Year Warranty
Pentair residential warranty coverage.
Who It's For
- Pool and spa owners whose heat load falls between the 250K and 400K BTU MasterTemp models
- Salt water and chemically demanding pools that benefit from a cupro-nickel heat exchanger
- Indoor and outdoor installations
- Anyone who wants maximum heating output from the compact 23-inch MasterTemp cabinet
Specifications
Heating Performance
| BTU Input | 300,000 BTU |
| Fuel Type | Natural Gas |
| Max Flow Rate | 120 GPM |
Construction
| Heat Exchanger | Cupro-Nickel (HD) |
| Control Type | Digital (LCD with Troubleshoot Icons) |
Installation
| Gas Connection | 0.75 in |
| Voltage | 120V / 240V |
| Frequency | 60 Hz |
| Phase | Single |
| Application | Indoor / Outdoor / Pool / Spa |
Physical
| Product Weight | 136 lb |
| Cabinet Dimensions | 23 W × 28.2 D × 21 H in |
| Shipping Dimensions | 36 × 25 × 30 in |
Approvals & Warranty
| Certifications | CSA Certified |
| Energy Efficient | Yes (Green Certified) |
| Warranty | 2 Years |
What's in the Box
- Pentair MasterTemp 300K BTU Natural Gas Heater
- Union Fittings
- User Manual
Warranty
The MasterTemp 300K BTU NG comes with a 2-year manufacturer warranty from Pentair. Clearflow Pool Supply is an authorized Pentair dealer and will assist with any warranty service needed.
Downloads
Frequently Asked Questions
Where does the 300K BTU fit in the MasterTemp lineup?
The MasterTemp is available in 125K, 200K, 250K, 300K, and 400K BTU sizes. The 300K sits between the 250K (suited for pools up to ~30,000 gallons) and the 400K (suited for pools up to ~50,000 gallons). All full-size MasterTemp models share the same 23-inch wide cabinet, cupro-nickel heat exchanger, and LCD display.
Does this heater require professional installation?
Yes. Gas heater installation involves connecting to a natural gas supply line, electrical wiring, and proper venting. A licensed pool contractor or plumber must perform the installation to ensure safety, local code compliance, and warranty validity.
Is it compatible with salt water pools?
Yes. The heavy-duty cupro-nickel heat exchanger provides superior resistance to salt water corrosion, making the MasterTemp 300K a strong choice for salt water pool installations.
What size pool is the 300K BTU suitable for?
As a general guideline, 300,000 BTU is typically suited for pools in the 25,000–40,000 gallon range depending on climate, desired temperature rise, and heat loss factors. A licensed pool professional can calculate the correct BTU requirement for your specific pool and location.
Can it be used indoors?
Yes. The MasterTemp is rated for both indoor and outdoor installation. Indoor installations require proper venting per local code. Consult the install guide and a licensed contractor for indoor venting requirements.