OEM Goodman 150°F Primary Limit Switch for AMH81155CNAA — B1370198

The Goodman B1370198 is a genuine OEM 150°F primary (high) limit switch for the Goodman/Amana AMH81155CNAA gas furnace and compatible models. Mounted through the heat exchanger deck in the supply-air stream, this normally-closed switch monitors plenum temperature and shuts off the burners if the furnace overheats — the primary overheat protection on the appliance.

A common symptom of a failing primary limit is short-cycling on heat: the burners light, the temperature climbs too fast (often from restricted airflow), and the limit opens to stop the burners while the blower keeps running. A switch that has failed open will prevent the furnace from heating at all.

• Trip temperature: 150°F (primary/high-limit)
• Type: normally-closed disc/insert thermal limit switch
• Function: primary overheat protection for the heat exchanger deck
• Fit: Goodman/Amana AMH81155CNAA and compatible furnaces
• OEM part number: B1370198

OEM vs. Generic: The primary limit's trip temperature and insert length are matched to the furnace's specific heat exchanger and airflow. Installing a generic limit with the wrong rating or probe length leads to nuisance trips or inadequate protection. This genuine Goodman B1370198 is factory-calibrated to 150°F with the correct mounting footprint.

Install difficulty: Moderate. Turn off power, remove the burner-compartment or deck panel, unscrew the switch, transfer the wiring, and seat the new switch in the same opening. Because short-cycling is usually caused by airflow restriction, inspect the filter, blower, and ductwork before returning the furnace to service.