Contactors & Starters

A contactor is an electrically operated switch inside the outdoor unit of an air conditioner or heat pump that controls the flow of high-voltage power to the compressor and condenser fan motor. Surplus HVAC contactors and starters handle this switching function in both residential and commercial condensing units.

When the thermostat calls for cooling, it sends a low-voltage signal that energizes the contactor's coil, closing the contacts and completing the high-voltage circuit that starts the outdoor unit. Without a functioning contactor, the outdoor unit cannot receive power, even if the thermostat, air handler, and refrigerant charge are all in good condition.

A contactor is a switching device that opens and closes a high-power circuit; in HVAC applications, it controls the compressor and condenser fan but does not include built-in overload protection. HVAC motor starters for sale combine a contactor with an overload relay, which monitors motor current and interrupts power if the motor draws excessive current, protecting it from damage due to overheating or mechanical binding.

HVAC condensing units most commonly use contactors; motor starters are more common in commercial HVAC equipment where fan motors, blowers, and pumps require continuous overload protection.

All contactors and starters in the Surplus City Liquidators inventory are new surplus HVAC parts that have never been installed. This is manufacturer overstock, not returns, pull-outs, or rebuilt components.

Surplus City sources directly from manufacturers, acquiring excess production inventory that was not sold through normal distribution channels. Buyers receive new products in original packaging at below-distribution pricing; the discount reflects excess supply, not reduced quality.

Common signs that an AC contactor replacement is needed include the outdoor unit humming but not starting, the system short cycling (turning on and off rapidly), or the unit running continuously without shutting off.

Visible indicators include pitted or burned contact surfaces, black burn marks on the housing, or a plunger that is physically stuck in the open or closed position. A multimeter set to continuity mode can confirm whether the contacts are functioning. A contactor that fails to show continuity when energized, or that shows continuity when de-energized, needs to be replaced.

The Surplus City Liquidators collection includes brand-name contactors and starters from leading HVAC and electrical manufacturers; specific brands vary based on current manufacturer surplus availability.

Common brand names carried in this category include Honeywell, White-Rodgers, Emerson, GE, Eaton, Siemens, and Carrier-branded components, among others. Inventory turns regularly as new manufacturer surplus is acquired; checking the collection page directly gives the most current picture of available brands and part numbers.

Proper HVAC contactor compatibility depends on matching the replacement unit to the original's specifications: coil voltage (typically 24V for residential systems), ampere rating, number of poles, and the number of normally open contacts.

The existing contactor's label or the unit's wiring diagram, usually affixed inside the service panel, will list the required specifications. Ordering by part number is the most reliable method when the original part is still intact. Cross-reference guides are widely available for common HVAC contactors when the original part number is no longer legible.

Single-pole contactors switch one leg of a 240V circuit and appear in some smaller or older residential AC units; double-pole contactors switch both legs simultaneously and are the standard configuration for most modern residential and commercial condensing units.

The nameplate on the existing contactor and the unit's wiring diagram will specify the required pole configuration. Substituting a single-pole for a double-pole (or vice versa) is not an acceptable replacement. When in doubt, match the original part number exactly. The coil voltage, amp rating, and pole configuration all need to align for safe, code-compliant operation.

Brand-new discount HVAC contactors from name manufacturers carry the same ratings, listings, and performance specifications as units purchased at full distribution pricing.

"Discount" in this context describes the pricing model, which entails manufacturer overstock acquired and resold at below-distribution cost, not a reduction in product quality, component rating, or manufacturer backing. HVAC contractors source replacement parts through surplus channels as a standard practice to maintain margins without compromising installation quality.

Surplus City Liquidators ships orders to customers across the contiguous United States in addition to offering local pickup. The online store supports direct ordering; shipping options, carrier selection, and estimated timelines are available at checkout.

Local pickup is available at various Surplus City showroom locations. Check online for availability.

The optional Surplus City Warranty provides 30 days of coverage from the date of delivery and is available for individual purchase at the time of order. Eligibility applies to undamaged items meeting program requirements. Confirm current category coverage with Surplus City directly before ordering.

Surplus City Liquidators sells all contactors and starters as brand-new, manufacturer-sourced components in original packaging. Customers with questions about product specifications or sourcing documentation can contact Surplus City directly.