Robertshaw 803A Line-Voltage Thermostat for Cooling | Mercury-Free SPST

Overview

The Robertshaw 803A is a mercury-free line-voltage thermostat with SPST action, designed to deliver reliable cooling control across a variety of setups. Its bimetal temperature sensing offers stable response and predictable cycling in daily use.

This thermostat covers a practical range from 50°F to 90°F (10°C to 32°C), helping you dial in comfortable temperatures without guesswork. It works with a range of loads and is suitable for retrofit into many existing electric heat or cooling configurations.

Key features

• Mercury-free operation for easier handling and disposal.
• Temperature display for quick at-a-glance setpoint checks.
• Bimetal sensing provides improved thermal performance and cycling stability.
• J-Box compatibility speeds installation and keeps wiring tidy.
• Positive-off switch for reliable shutdown of the HVAC system when needed.
• Universal replacement design supports retrofitting many existing electric thermostats.

Technical at a glance

• Temperature control range: 50°F to 90°F (10°C to 32°C).
• Electrical ratings: 25A at 250 VAC RES; 18A at 277 VAC RES; 1 HP at 125 VAC; 2 HP at 250 VAC; 125 VA Pilot Duty.
• Form factor: Line voltage SPST thermostat for cooling applications.
• Compatibility: J-Box-ready; designed for easy retrofit with many electric heat setups.

Real-world use scenarios

Ideal for replacing aging, mercury-containing thermostats in residential or light commercial cooling systems. Its compact design fits standard electrical boxes, while the clear display helps technicians verify settings during commissioning. The mercury-free design reduces disposal considerations and simplifies ongoing maintenance.

As a universal replacement option, it supports straightforward retrofit paths across different brands and models that rely on line-voltage SPST cooling controls.