Pentair MasterTemp® Natural Gas High Performance Heater with Cord 125K BTU
The Pentair MasterTemp® Natural Gas High Performance Heater with Cord 125K BTU brings the energy savings and advanced operating features of larger heaters to a remarkably affordable, compact package. With revolutionary pre-mixed gas combustion technology, the MasterTemp 125 delivers 82% thermal efficiency — the highest of any heater in its category.
Its 1-1/2 inch plumbing is ideal for smaller applications including above-ground pools, spas, and in-ground pools up to 15,000 gallons. Featuring the first-ever rotating digital display offered in its class, lightweight compact design, and cord included — it's easier to install than any other heater in its class, reducing labor costs and saving you money. 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
125,000 BTU — Highest Efficiency in Its Class
82% thermal efficiency via pre-mixed gas combustion technology — the best in the 125K BTU category.
Above-Ground and Small In-Ground Pools
1-1/2 inch plumbing ideal for above-ground pools, spas, and in-ground pools up to 15,000 gallons.
Pre-Mixed Gas Combustion Technology
Revolutionary combustion system delivers best-in-class efficiency.
Rotating Digital Display
First-ever rotating digital display in its class — valuable information at the touch of a button.
Lightweight, Compact Design
Easier to install than any other heater in its class — reduces labor costs.
Cord Included
Power cord included for straightforward electrical connection.
Energy Efficient
Green certified — energy savings that were previously only available in much larger heaters.
2-Year Warranty
Pentair residential warranty coverage.
Who It's For
- Above-ground pool owners wanting a compact, efficient natural gas heater
- Spa owners needing a purpose-sized heater for a smaller water volume
- In-ground pool owners with pools up to 15,000 gallons
- Anyone who wants the easiest-to-install heater in the 125K BTU class
Specifications
Heating Performance
| BTU Input | 125,000 BTU |
| Thermal Efficiency | 82% |
| Fuel Type | Natural Gas |
| Combustion Technology | Pre-Mixed Gas |
| Max Flow Rate | 70 GPM |
| Pool Size | Up to 15,000 gallons (in-ground); above-ground pools and spas |
Construction
| Control Type | Digital (Rotating Display) |
| Plumbing Size | 1-1/2 in |
Installation
| Gas Connection | 0.75 in |
| Voltage | 120V / 240V |
| Amperage | 15A |
| Frequency | 60 Hz |
| Phase | Single |
| Application | Indoor / Outdoor / Pool / Spa |
| Cord Included | Yes |
Physical
| Product Weight | 100 lb |
| Cabinet Dimensions | 21 W × 23 D × 21 H in |
| Shipping Dimensions | 23 × 36 × 25 in |
Approvals & Warranty
| Energy Efficient | Yes (Green Certified) |
| Warranty | 2 Years |
What's in the Box
- Pentair MasterTemp 125K BTU Natural Gas Heater
- Power Cord
- Union Fittings
- User Manual
Warranty
The MasterTemp 125K BTU with Cord 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
Is the MasterTemp 125 suitable for above-ground pools?
Yes. The MasterTemp 125 is specifically designed for above-ground pools, spas, and in-ground pools up to 15,000 gallons. Its 1-1/2 inch plumbing matches the smaller diameter plumbing common in above-ground pool systems.
Does this heater require professional installation?
Yes. Gas heater installation involves connecting to a natural gas supply line and proper venting, even for smaller units. A licensed pool contractor or plumber should perform the installation to ensure safety, local code compliance, and warranty validity.
What is pre-mixed gas combustion technology?
Pre-mixed combustion blends gas and air before ignition, resulting in a more complete, efficient burn compared to traditional diffusion combustion. This is what allows the MasterTemp 125 to achieve 82% thermal efficiency — the highest in the 125K BTU class.
Does it have a digital display?
Yes. The MasterTemp 125 features the first-ever rotating digital display offered in the compact heater class — providing temperature readout and operating status information at the touch of a button.
How does this compare to the 250K BTU MasterTemp models?
The MasterTemp 125 uses 1-1/2 inch plumbing (vs. 2 inch on larger models), is designed specifically for smaller pools and spas up to 15,000 gallons, and uses pre-mixed combustion technology unique to this model. For pools over 15,000 gallons, step up to the 250K BTU or 400K BTU MasterTemp models.