Long Term KST200 & KST203 Electric Water Heater Thermostat Kit – Upper & Lower Thermostats for Most Heaters

Overview

Upgrade your electric water heater with the Long Term KST200 and KST203 thermostat kit. This thoughtful pair of components is designed to replace or upgrade temperature regulation in many double-element heaters, helping you regain control over hot water delivery. The kit includes one upper thermostat and one lower thermostat that operate in a non-simultaneous fashion, coordinating heat without overlap. It supports a broad voltage range from 120 to 480 volts, offering installation flexibility across different wiring setups and locales.

With Thermo-O-Disc TOD style technology and exchangeability with Apcom style parts, these thermostats are built to adapt to a variety of brands and models. This flexibility can simplify sourcing and reduce downtime when a full unit replacement isn’t desirable, making maintenance feel more approachable for DIY enthusiasts and pros alike.

What’s included and key specs

• Contains 1 x Upper thermostat and 1 x Lower thermostat with non-simultaneous operation; compatible across 120V–480V systems
• Temperature range adjustable from 90F to 150F; TOD style; exchangeable with Apcom style
• Designed to fit a wide array of brands including Whirlpool, Bradford White, Craftmaster, General Electric, Kenmore, Rheem, A O Smith, Reliance, Ruud, State, Mor-Flo and APCOM
• One year warranty with customer support and return options if needed

Compatibility and practical notes

• Retrofit-friendly design for many two-element electric water heaters
• Ensure correct pairing of upper and lower units for your model and follow standard electrical safety practices

In real-world use, this kit is intended to support steadier temperature control and reliable hot water delivery when installed in compatible systems. Results can vary by heater and setup, but the parts are designed to offer a practical upgrade path without replacing the entire tank. The warranty provides added peace of mind, reflecting the manufacturer’s confidence in reliable performance and customer support.