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Furnace Parts DIY
3 Limit Switch 543-004 replacement part for AmericanStandard furnaces

Furnace Parts DIY

543-004

$50.00

+5% Tax • Shipping calculated at checkout.

U.S. Duties/Taxes, if applicable, may be due at time of delivery.

Name

3" HIGH LIMIT SWITCH L170-30F

Low stock — only 5 left

Pickup available at 75 Blue Mountain St #3, Coquitlam

Usually ready in 24 hours

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Local Pickup

Not sure this fits your furnace? Call us — we're happy to help

Product Details

Description

Ensure your heating system operates safely with this premium 3-inch high limit switch. Designed as a critical safety component for residential gas furnaces and forced-air HVAC systems, this thermal limit control prevents dangerous overheating by monitoring internal plenum temperatures. The switch is engineered to automatically interrupt the heating cycle when temperatures reach the 170-degree Fahrenheit threshold, protecting your heat exchanger and home from potential damage. Featuring a 30-degree differential for a reliable automatic reset once the unit cools to 140 degrees, this high limit sensor is an essential replacement part for restoring furnace safety and efficiency. Ideal for HVAC maintenance and heater repairs, this durable limit control switch provides consistent climate control performance and equipment protection.

Specifications

Type
High Limit Control Switch
Size
3-inch probe
Dimensions
3 in
Application
Residential gas furnaces, forced-air heating systems, and HVAC units requiring thermal overload protection.
Specifications
Open Temperature: 170°F; Close Temperature: 140°F; 30°F Differential; Automatic Reset; L170-30F Calibration.

Not sure this is the right part?

Our team is happy to help you verify compatibility before you order. We'll confirm it fits your specific furnace model.

1-778-759-9864

Mon–Sat 8AM–5PM PT · Or email parts@bcfurnace.com

Common questions

Will the 543-004 fit my furnace?

The 543-004 is a replacement part. Match your furnace model number on our site to confirm the fit. This 3 Limit Switch is backed by our 100% compatibility guarantee — if it doesn't fit your furnace, we'll make it right.

How do I know if the 543-004 is compatible with my furnace?

The easiest way is to match the part number (543-004) with your furnace model number. Visit the homepage and enter your model number in the search bar — our system will show all compatible 3 Limit Switches for your specific unit. You can also call our technicians at 1-778-759-9864 for free compatibility verification.

How fast can I get the 543-004 shipped?

Most 3 Limit Switches including the 543-004 ship within 1–2 business days from our warehouse. We ship across Canada and the United States, and worldwide, with tracking on every order. For urgent furnace repairs, contact us at 1-778-759-9864 for expedited shipping options.

Can I pick up the 543-004 at your store?

Yes! Local pickup is available at our Coquitlam, BC location: 75 Blue Mountain St #3. 3 Limit Switches orders are usually ready within 24 hours. Call us at 1-778-759-9864 to confirm the 543-004 is in stock before visiting.

Still not sure this is the right part? Call 1-778-759-9864 and we will check your model number with you.

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