The JD-2 differential switch is engineered for a compression fit installation

2 Minute Warm Up Time

the 1171325 should show continuity (0 Ohms or a "beep")

Exceeding this limit can cause damage to the internal components or trigger safety relief

Utilizing high-grade HVAC replacement parts like this 025-37888-000 ensures that lubricant viscosity remains within manufacturer specifications

Carrier HH18HA147 Limit Switch 319852-301 The JD-2 differential switch isThe Carrier HH18HA147 Limit Switch is a critical safety component designed for precise thermal monitoring within furnace heat exchangers and air handlers. Engineered as a high limit protection device, this switch is a direct replacement for HH18HA147A and functions by opening the electrical circuit if internal plenum temperatures exceed safe operating parameters. This prevents thermal stress on the heat exchanger and ensures the system operates within