ERP ERHH12ZB240 Furnace Plenum High Limit Switch For: Carrier Bryant SHL509 | Replaces HH12ZB240

Furnace Plenum High-Limit Switch For: Carrier, Bryant HH12ZB240, SHL509, ERHH12ZB240

Safety first: A qualified HVAC technician should disconnect and verify isolation of electrical power before service.

Restore safe furnace operation with this ERP replacement plenum high-limit switch for compatible Carrier and Bryant furnace plenum applications. The Supco gas-furnace limit table maps HH12ZB240 to SHL509: it opens at 240°F, closes at 210°F, with a 30°F differential, SPST. Repeated high-limit shutdowns require diagnosis of overheating, airflow, and the limit control. Verify probe insertion length, mounting, terminals, and load rating against the original before ordering. A similar temperature marking alone does not establish fit.

Product Details

• SKU: ERHH12ZB240
• UPC: 840993028427
• Opens at: 240°F
• Closes at: 210°F (30°F differential)
• Type: SPST temperature-limit switch

Compatible Part Numbers

• HH12ZB240
• SHL509
• ERHH12ZB240

Key Features

• Direct replacement: Replaces the listed furnace plenum high-limit switch part numbers.
• Overheat protection: Opens at 240°F and resets at 210°F in the supply plenum.
• Matched control: SPST switch with a 30°F differential.
• Installation check: Match the probe insertion length, mounting, terminals, and load rating with the original.

Fixes These Symptoms

• Furnace shuts down repeatedly on high-limit
• Burners cut off before the thermostat is satisfied
• Blower runs but heat output is interrupted
• Limit switch is stuck open or fails its continuity test

Compatible Brands

Carrier, Bryant

Compatible Models

Fits various models. Please verify compatibility with us before ordering

Installation Instructions

1. Disconnect and verify isolation of electrical power before service.
2. Confirm the original cutoff and reset temperatures, terminals, insertion length, and mounting.
3. Investigate overheating or airflow problems before replacing the limit switch.
4. Install the new switch and connect the wiring to the matching terminals.
5. Follow the furnace service manual and verify safe operation before returning the system to service.

Never bypass the switch or install a higher-temperature limit to prevent shutdowns. Use a qualified HVAC technician for this repair.

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Safety Disclosure

Prop 65 Warning: Cancer and Reproductive Harm – www.P65Warnings.ca.gov