SureSwitch Contractor Upgrade

What Is A Contactor?

The contactor in your AC system acts as a switch to power up the compressor when your thermostat requests a cooling cycle. When your unit is off and power is not needed, the copper contacts shown below are slightly lifted in an open position, breaking the electrical circuit. Once your thermostat decides it’s time to begin cooling, it sends a signal to the electrical contacts telling them to interlock the contacts so that electricity can flow freely. After your thermostat is satisfied it tells the contacts to disengage and cut off the energy supply.



The main purpose of the contactor is to control the flow of electricity throughout the unit.If the contactor fails, your AC will not receive the electricity it needs and therefore cannot operate properly.

Contactor failure is a common occurrence. In fact, 2 million contactors are replaced each year. According to Emerson Climate Technologies, 25% of all service calls are due to a bad contactor. A failed contactor will either keep your unit running continuously or keep it from running at all.

Metals that are exposed to excessive voltage and heat will begin to deteriorate over time. This process, known as pitting, is a common cause of contact failure in AC systems. Contact pitting from arcing, debris or pests eventually causes the surface to stick which creates a constant circuit of electricity. If this circuit is left on for a long period of time, it will allow liquid refrigerant to flow into the compressor, ultimately rendering it ineffective.


Sureswitch contractor

The SureSwitch Contactor Upgrade is a universal electronic replacement for mechanical compressor contactors. It is a state-of-the-art contactor with a short-cycle timer, brownout protection, and a long-life sealed switch.

The SureSwitch Contactor has been performance tested. After bearing extensive testing on Copeland 5-ton scroll compressors, this product has proven it’s reliability and longevity.

The SureSwitch advantage:

  • Solid-state switch prevents arcing
  • Sealed relay keeps foreign objects out
  • Integrated brownout and short cycle protection
  • Universal mounting
  • Same wiring as a traditional contactor

What are the Benefits?

  • 5x contactor life
  • Totally sealed switch to keep out ants and debris
  • Microprocessor control nearly eliminates contact welding and pitting
  • Ideal install with new preventative maintenance contracts
  • Compressor is protected from bownouts and short-cycling
  • Save on pest control treatments
  • Prevent recurring failure
  • Backed by 5-year limited warranty
  • Added short cycle and brownout protection

Product Features

Brownout Protection

  • Auto shut off when line voltage drops below 180VAC for more than 4 seconds
  • Operation will resume when line voltage returns to a minimum of 190VAC

Cold Load Pickup Mitigation

  • After a power outage, SureSwitch will delay operation for 3 minutes (to protect the compressor) and then a randomization algorithm will delay operation by an additional 5-90 seconds to protect the grid

Test Button

  • Enables installer to easily confirm proper installation without gaining access to the premise

Compressor Protection

  • Extends life of HVAC equipment
  • Lifetime use of ~20 years, roughly 5x the life of a traditional contactor

Random Start Delay

At power-up and when SureSwitch recovers from a brownout, a random start delay of 5-90 seconds will be activated. This delay is in addition to the short cycle delay. During this delay, the compressor will not be energized, even if a call for compressor operation is present. The random start delay can help reduce spikes in power consumption when multiple loads are re-energized after a blackout or brownout.

Short Cycle Protection

At power-up, and any time the compressor is de-energized, SureSwitch will activate a three minute short cycle delay. During this delay, the compressor will not be energized, even if a call for compressor operation is present, in order to prevent compressor damage due to rapid on and off cycling. Normal operation resumes when the delay expires.

Line Voltage Brownout Protection

Brownout protection will de-energize the compressor and fan if line voltage drops below 180VAC for more than four seconds during a call for compressor operation. Compressor operation will not resume until line voltage returns to a minimum of 190VAC. In addition, SureSwitch will not attempt to start the compressor if line voltage is less than 187VAC.

Lifetime Cycle Count

A count of compressor cycles since the control was installed is stored in the control’s memory.

To ensure your peace of mind, upgrade to the Emerson SureSwitch Contactor to protect your system from contactor failure and future breakdowns.

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