Product Overview

Heat large residential pools and spas quickly with the Pentair MasterTemp 400 Natural Gas Heater. Part number 460736 delivers 400,000 BTU of heating power in a compact cabinet designed for dependable performance, efficient operation, and convenient equipment-pad installation.

The MasterTemp uses an induced-draft combustion system that carefully manages the air-and-gas mixture for reliable heating. Its hot-surface ignition system eliminates the need for a standing pilot, helping reduce wasted fuel while providing automatic electronic startup.

A digital temperature controller gives pool owners convenient access to temperature settings and operating information. Built-in diagnostic indicators help qualified service technicians identify operating problems more efficiently.

The heater connects directly to compatible 2-inch Schedule 40 PVC plumbing and can operate from either 120V or 240V electrical service when configured according to Pentair’s installation instructions.

Key Features

Powerful 400,000 BTU heating capacity

Designed for natural-gas operation

Suitable for residential pools and spas

Low-NOx combustion design

Compact equipment-pad footprint

Digital temperature controls

Built-in operating diagnostics

Hot-surface electronic ignition

No standing pilot required

Quiet induced-draft operation

Copper heat exchanger

Direct 2-inch PVC plumbing connections

Compatible with select pool automation systems

Reversible water connections support flexible installation

Corrosion-resistant exterior cabinet

Specifications

Package Contents

• One Pentair MasterTemp 400 natural-gas heater
• Integrated digital control panel
• Factory-installed copper heat exchanger
• Plumbing connection components supplied by Pentair
• Installation and operating documentation

Gas piping, shutoff valve, electrical wiring, venting, automation equipment, pressure-relief valve, plumbing materials, and installation labor are not included unless specifically stated.

Warranty & Compatibility

Control and Automation

The onboard digital controller allows the desired pool or spa temperature to be selected directly at the heater. The MasterTemp can also interface with compatible external automation systems through the heater’s remote-control connections.

Automation equipment, communication wiring, additional relays, and optional accessories are not included.

Installation Requirements

Professional installation is required. The installer must verify natural-gas supply volume, pipe sizing, inlet pressure, electrical service, water flow, plumbing layout, clearances, bonding, drainage, and ventilation.

Indoor or outdoor-shelter installations require a properly designed venting and combustion-air system. The heater must never be installed in an enclosed area without approved ventilation.

Gas-pipe sizing must be based on the heater’s 400,000 BTU demand, total pipe length, available supply pressure, and other appliances connected to the same gas system. An undersized gas line can cause ignition failures, poor combustion, and unreliable heating.

Proper pool-water chemistry and circulation must be maintained to protect the copper heat exchanger from scale, corrosion, and premature failure.

Warranty Information

Pentair currently lists a two-year standard warranty for professionally installed MasterTemp and Max-E-Therm heaters. Products purchased online receive a one-year parts-only warranty. Eligibility depends on purchase channel, proof of purchase, installation, registration, and Pentair’s current terms.