2845-3181 Coleman limit switch L170-30F

The Coleman 2845-3181 is an OEM L170-30F high-limit switch used in Coleman, York, and Luxaire furnaces. This 3-inch insertion-depth safety switch opens at 170°F and automatically resets after a 30°F temperature drop, protecting the heat exchanger from overheating caused by airflow restriction, dirty filters, blower failure, or duct blockage.

This limit is part of the Coleman/York S1 series and is commonly replaced when the furnace short-cycles or shuts down prematurely. Using the OEM switch ensures correct temperature response and maintains furnace safety certification.

Coleman 2845-3181 limit switch. L170F-30. Thermodisc size 60T11-312623. Opens at 170 degrees, closes at 140 degrees Fahrenheit. Replaces 2845-318.

Technician Notes

• Trip Temperature: 170°F

• Differential: 30°F (auto-reset)

• Length: 3" insertion

• Circuit: SPST, normally closed

• Brands: Coleman, York, Luxaire

• Function: Opens on temperature rise to protect heat exchanger

• Common Symptoms:

  • Furnace starts then shuts off

  • Blower runs continuously

  • Short-cycling

• Always diagnose airflow issues first: dirty filter, blower failure, blocked return, closed registers.