Pentair MasterTemp® Digital IID Heavy Duty ASME Natural Gas Low NOx Heater 250K BTU
The Pentair MasterTemp® Digital IID Heavy Duty ASME Natural Gas Low NOx Heater 250K BTU combines the MasterTemp platform's proven efficiency and reliability with both ASME certification and heavy-duty cupro nickel tubing — the complete commercial-grade specification at 250K BTU. User-friendly indicator lights make operation and monitoring a snap, and the compact, super-quiet design won't intrude on poolside leisure.
Built by Pentair with ASME-certified construction, HD cupro nickel tubing rated for low pH, high flow, and heavy use, Digital IID ignition, Low NOx emissions, and 250,000 BTU natural gas output. 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
ASME Certified Construction
Required for many commercial pool installations — meets the most rigorous pressure vessel standards.
Cupro Nickel Tubing (HD)
Withstands low pH, high flow, and heavy use — the full HD specification.
250,000 BTU Natural Gas
Mid-range capacity in the ASME HD MasterTemp platform.
Digital IID Ignition
Intermittent Ignition Device — reliable electronic ignition without a standing pilot light.
Low NOx Certified
Meets low emissions standards — green certified.
Digital Indicator Lights
User-friendly indicator lights for simple operation and monitoring.
Compact, Quiet Design
Same 23-inch wide MasterTemp cabinet — super-quiet operation.
Indoor and Outdoor Rated
Suitable for both indoor and outdoor pool and spa installations.
2-Year Warranty
Pentair warranty coverage.
Who It's For
- Commercial pool installations requiring both ASME certification and HD cupro nickel tubing at 250K BTU
- Low pH, high flow, or heavy use applications where standard tubing isn't sufficient
- Salt water commercial pools at 250K BTU needing maximum material durability
- Anyone who needs the full commercial-grade MasterTemp spec — ASME + HD — at 250K BTU
Specifications
Heating Performance
| BTU Input / Output | 250,000 BTU |
| Fuel Type | Natural Gas |
| Ignition | Digital IID (Intermittent Ignition Device) |
| Emissions | Low NOx |
| Max Flow Rate | 120 GPM |
Construction
| Tubing Material | Cupro Nickel (HD) |
| Control Type | Digital (Indicator Lights) |
Installation
| Gas Connection | 0.75 in |
| Voltage | 120V / 240V |
| Frequency | 60 Hz |
| Phase | Single |
| Application | Indoor / Outdoor / Pool / Spa |
Physical
| Product Weight | 144 lb |
| Cabinet Dimensions | 23 W × 28.2 D × 21 H in |
| Shipping Dimensions | 36 × 25 × 30 in |
Approvals & Warranty
| Certifications | ASME Certified |
| Energy Efficient | Yes (Green Certified) |
| Warranty | 2 Years |
What's in the Box
- Pentair MasterTemp Digital IID HD ASME 250K Natural Gas Heater
- Union Fittings
- User Manual
Warranty
The MasterTemp Digital IID HD ASME 250K 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
How does this (461020) compare to the other 250K ASME model (460771)?
Both are ASME-certified 250K BTU MasterTemp natural gas heaters. The 461020 adds heavy-duty cupro nickel tubing — making it the full commercial spec for low pH, high flow, or heavy use applications. The 460771 uses standard heat exchanger materials and is suitable when ASME certification is required by code but HD tubing isn't needed for the water chemistry or application.
What does ASME certified mean for this heater?
ASME (American Society of Mechanical Engineers) certification means the heat exchanger was built to the most rigorous pressure vessel standards. Many commercial pool installations — hotels, fitness centers, aquatic facilities — require ASME-certified heaters per local code.
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 contractor must perform the installation to ensure safety, local code compliance, and warranty validity.
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 operating manual and a licensed contractor for indoor venting requirements.