Pentair MasterTemp® Liquid Propane High Performance Heater 400K BTU
The Pentair MasterTemp® Liquid Propane High Performance Heater 400K 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 user-friendly indicator lights 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, 400,000 BTU liquid propane output, best-in-class energy efficiency, Low NOx emissions, and a rustproof exterior — the MasterTemp 400K LP is the high-capacity propane heater for larger pools and demanding applications. CSA certified. Backed by a 2-year limited warranty.
⚠️ Professional Installation Required. Pool heater installation involves propane gas line connections and electrical wiring. Always use a licensed contractor to ensure safety, code compliance, and warranty validity.
Key Features
400,000 BTU Output
High-capacity liquid propane heating for larger pools and spas.
Liquid Propane Fuel
Ideal for locations without natural gas access — step up from the 250K LP for larger pools.
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.
Heats Up Fast
No long waits before enjoying your pool or spa.
Digital Indicator Lights
User-friendly indicator lights make system operation and monitoring a snap.
Low NOx Emissions
Eco-friendly and certified to outperform industry emission standards.
Rustproof Exterior
Tough exterior handles heat and weathers the elements year-round.
Manual Gas Shut-Off
Built-in manual gas shut-off when service is required.
2-Year Limited Warranty
Pentair residential warranty coverage.
Who It's For
- Larger pool owners without natural gas access who need maximum LP heating capacity
- Salt water and chemically demanding pools needing a cupro-nickel heat exchanger
- Indoor and outdoor pool installations requiring high BTU output
- Anyone stepping up from 250K BTU for faster heating of a larger body of water
Specifications
Heating Performance
| BTU Input | 400,000 BTU |
| Fuel Type | Liquid Propane |
| Emissions | Low NOx Certified |
| Max Flow Rate | 120 GPM |
Construction
| Heat Exchanger | Cupro-Nickel (HD) |
| Control Type | Digital (Indicator Lights) |
| Exterior | Rustproof |
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 Limited |
What's in the Box
- Pentair MasterTemp 400K BTU Liquid Propane Heater
- Union Fittings
- User Manual
Warranty
The MasterTemp 400K BTU LP comes with a 2-year limited manufacturer warranty from Pentair. Clearflow Pool Supply is an authorized Pentair dealer and will assist with any warranty service needed.
Downloads
Frequently Asked Questions
What is the difference between the 400K BTU and 250K BTU MasterTemp LP?
The 400K BTU model heats larger pools faster than the 250K BTU. Both share the same cabinet dimensions, cupro-nickel heat exchanger, CSA certification, and 2-year warranty. Choose 400K for pools over approximately 30,000 gallons, or when faster heat-up time is a priority in cooler climates.
Does the MasterTemp 400K LP require professional installation?
Yes. Propane heater installation involves connecting to a propane 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 this heater compatible with salt water pools?
Yes. The heavy-duty cupro-nickel heat exchanger provides superior resistance to salt water corrosion, making the MasterTemp 400K LP a strong choice for salt water pool installations.
What size pool is the 400K BTU suitable for?
As a general guideline, 400,000 BTU is typically suited for pools in the 30,000-50,000 gallon range, or for pools in cooler climates where faster heat-up time is needed. A licensed pool professional can calculate the correct BTU requirement for your specific pool and location.
Can this heater be used indoors?
Yes. The MasterTemp is rated for both indoor and outdoor installation. Indoor propane installations require proper venting per local code. Consult the install guide and a licensed contractor for indoor venting requirements specific to propane appliances.