Intermatic | 156T4042A | Heater Control (Fireman) Switch Kit

The Intermatic 156T4042A Fireman Switch Kit is a coordinated control solution for pool & spa equipment, designed to turn off a gas-fired heater ahead of the filter pump shutdown. By doing so it helps prevent overheating, water hammer, scale buildup and extends the service life of the heater. 

Key Features

• Turns off the heater approximately 20 minutes prior to filter pump shutdown, automatically. 

• Rated for 250 VAC, 10 A, 60 Hz. 

• Designed for use with pool/spa heater and filter pump coordination to improve longevity of heating equipment. 

• Compatible with Intermatic timer/control panels and fire-man switch ready timer systems. 

• Simple installation kit—service-tech friendly upgrade for older systems.

Product Overview
The Intermatic 156T4042A Fireman Switch Kit is aimed at professional pool and spa installers and service technicians who want to integrate a proper shutdown sequencing device into heater/filter pump systems. When a filter pump continues to run while the heater is off, or when a heater remains on after flow has ceased, there can be issues such as overheating, scale formation or manifold damage. This switch addresses that by automatically cutting heater power ahead of the pump shutdown period, helping maintain equipment reliability and service life.

From a catalog perspective, this component falls under “Automation & Control Parts – Heater / Filtration System Coordination” and should be described as a “heater-control/fireman switch kit for pool/spa heater and pump coordination.” It offers advantage in reducing maintenance, protecting heater internals and improving system performance.