Product Overview

Pentair MasterTemp 400 (460736) – Premium 400,000 BTU Natural Gas Pool & Spa Heater
The MasterTemp 400 is Pentair’s flagship high-output pool and spa heater, delivering exceptional heating speed and efficiency for large residential and commercial-grade pools. Built with robust materials and advanced digital controls, it combines powerful performance with a compact footprint, giving you dependable heat when you need it most.

• Heating Capacity: 400,000 BTU Input

• Fuel Type: Natural Gas

• Electrical: 120/240 V Single Phase, 60 Hz

• Weight: ≈ 140 lbs

• Warranty: 2 Years (when professionally installed)

Call-out Badges: Low NOx Certified • Eco-Select Choice • High Output • Commercial-Grade Performance

Ideal For

• Large in-ground residential pools or combination pool + spa systems

• Property owners wanting rapid heat-up and consistent water temperature

• Replacing older 350–400 K BTU gas heaters with an efficient, compact alternative

• Users who need dependable operation through extended swim seasons

Key Features

400,000 BTU Heating Power — The most powerful model in the MasterTemp line, providing quick, even heating for high-volume pools and spas.
Why it matters: Perfect for large installations where performance and speed are critical.

High-Efficiency Combustion System — Optimized burner and heat-exchanger design deliver more heat to the water and less wasted energy.
Why it matters: Saves fuel and lowers operating costs.

Durable Composite Cabinet — Rust-proof, weather-resistant exterior protects against corrosion and UV damage.
Why it matters: Reliable performance in any climate.

Rotating Digital Display & Self-Diagnostics — Simplifies setup and maintenance with clear digital readouts and easy-access controls.
Why it matters: Reduces downtime and improves user control.

Low NOx Emission Design — Certified to meet strict environmental standards.
Why it matters: Cleaner operation with reduced emissions and improved efficiency.

Benefits

• Fast Heating: Brings large pools or spas to temperature quickly

• Energy Efficient: Reduces fuel consumption without sacrificing power

• Quiet Operation: Low-noise design keeps backyard environments peaceful

• Rugged Longevity: Built to handle high demand and harsh outdoor conditions

• Compact Design: Fits standard equipment pads for easy replacement installs

Specs & What’s in the Box

Specifications

• Dimensions: 23″ W × 32.6″ D × 28″ H

• Weight: ≈ 140 lbs

• Materials: Composite cabinet with copper or cupro-nickel heat exchanger option

• Gas Connection: ¾″ NPT

• Electrical: 120/240 V single phase connection

• Fuel Type: Natural Gas

In the Box

• Pentair MasterTemp 400 Natural Gas Heater (460736)

• User manual and installation guide

• Mounting hardware and fittings

Compatibility & Replacements

Works with: Large residential and light-commercial in-ground pool and spa systems using natural gas supply
Replaces: Older Pentair MiniMax and other 350–400 K BTU heaters
Not compatible with: Propane systems (use model 460737) or ASME-certified installations (model 461058)

Trust Builders

• ⭐⭐⭐⭐⭐ Pentair’s top-rated high-capacity heater for residential use

• Backed by a two-year limited warranty

• Supported nationwide through Pentair’s authorized dealer and service network

• Designed and assembled in the USA

Install Steps (Compact)

1. Turn off power and gas supply

2. Remove existing heater and prepare plumbing connections

3. Mount MasterTemp 400 level on pad and connect water and gas lines

4. Connect 120/240 V power and configure digital controls

5. Test operation, verify ignition, and check for leaks and proper heating performance