What amp contactor do I need for my Lennox system?

The correct replacement for Lennox model OEM Lennox Contactor 2-Pole 120V 30A — 72P51 is this exact part. It is the factory-specified replacement with exact OEM specifications. Using a part with different specifications can cause equipment damage or void your warranty. You can verify this by checking the data plate on your Lennox equipment which lists the model number OEM Lennox Contactor 2-Pole 120V 30A — 72P51.

My AC clicks but the compressor does not turn on. What is wrong?

Clicking from the outdoor unit without the compressor starting usually means a worn contactor. The contactor is the relay that sends power to the compressor. When its contacts are pitted or worn, it clicks but cannot establish a solid electrical connection. Other symptoms: visible pitting or burn marks on the contactor face, AC works intermittently, or buzzing from the contactor.

Lennox

OEM Lennox Contactor 2-Pole 120V 30A — 72P51

Name: OEM Lennox Contactor 2-Pole 120V 30A — 72P51
Brand: Lennox
SKU: LNX-72P51
Price: 28.95 USD
Availability: InStock

SKU: LNX-72P51 Brand: Lennox

$28.95 $38.95

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The genuine OEM Lennox 72P51 is a 2-pole contactor rated for 120 volts and 30 amps. This electromechanical switch controls power to the compressor and condenser fan motor in your Lennox outdoor unit, engaging whenever the control circuit calls for cooling and safely handling the high inrush current these motors draw at startup.

Common failure symptoms: A failing 72P51 contactor often shows up as an outdoor unit that hums but won't run, a loud buzzing or chattering at the contactor, visibly pitted, corroded, or burnt contacts, or contacts that weld shut and keep the unit running non-stop. You may also experience intermittent cooling as the worn contacts make poor electrical connection.

Why OEM matters: The Lennox 72P51 is matched to your system's exact coil voltage and current rating. Using a non-OEM contactor with the wrong coil voltage or lower amp rating risks chattering, overheating, and premature burnout that can cascade into compressor damage. Choosing the factory-correct part guarantees proper fit, reliable switching, and the full rated service life your Lennox equipment was designed for.

Shipping Information

Orders placed before 3PM CST ship same business day
Standard delivery: 2-5 business days
Express shipping available at checkout
Free shipping on orders over $75
Tracking number emailed upon shipment

Return Policy

30-day returns on unused parts in original packaging
Electrical parts (capacitors, contactors, control boards) are final sale once installed
Email info@nationalhvacparts.com to initiate a return
Refunds processed within 5-7 business days

OEM Lennox Contactor 2-Pole 120V...

$28.95

Frequently Asked Questions

Does this Contactor fit my Lennox OEM Lennox Contactor 2-Pole 120V 30A — 72P51?

Yes. This is the factory-specified OEM contactor for the Lennox OEM Lennox Contactor 2-Pole 120V 30A — 72P51. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.

How do I replace the contactor on my Lennox OEM Lennox Contactor 2-Pole 120V 30A — 72P51?

Difficulty: Medium (30–45 min)
Step 1: Turn off breaker. Step 2: Open condensing unit panel. Step 3: Photograph ALL wiring on the contactor. Step 4: Label each wire with tape. Step 5: Disconnect wires and remove old contactor. Step 6: Mount new contactor, reconnect wires matching your photo. Step 7: Restore power and test.

My AC clicks but the compressor won’t turn on. What’s wrong?

Clicking from the outdoor unit without the compressor starting = worn contactor. The contactor sends power to the compressor. When its contacts are pitted, it clicks but can’t make solid contact. Look for: visible pitting/burn marks on the contactor face, intermittent operation, or buzzing.

Is this contactor compatible with Bryant or Payne too?

Many Lennox parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.

Should I use OEM or aftermarket for my Lennox contactor?

OEM recommended for reliability and warranty compatibility. OEM parts match exact factory specifications for proper fit, performance, and safety. While aftermarket alternatives cost less upfront, the risk of improper fit and reduced lifespan usually makes OEM the better value long-term.

How fast does National HVAC Parts ship?

Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.

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OEM Lennox Contactor 2-Pole 120V 30A — 72P51

Shipping Information

Return Policy

Frequently Asked Questions