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FAQ | SureStarts

  • What is a SmoothStarter?
    SmoothStarter is a small, “soft starter” for systems that use compressors that start under a “zero load” condition. They were developed specifically to reduce inrush current (Locked Rotor Amperage - LRA) in heating and air conditioning (HVAC) systems. As grid demand increases, products like SmoothStarter will likely be required in every home. SmoothStarters use a programmed circuit board and start capacitor to measure the characteristics of a motor and then optimize electrical input over several start cycles until the starting inrush current, or Locked Rotor Amp (LRA) is significantly reduced.
  • Where is this technology installed?
    SmoothStarter technology is used in HVAC systems to reduce inrush current (Locked Rotor Amperage - LRA) in heating and air conditioning (HVAC) systems in applications where strict regulations on appliance current draw (amperage). Smooth starter technology has been installed in over 300,000 HVAC applications worldwide and is currently popular in water source heat pump manufacturing in the US; and is also being used for air source heat pumps and air conditioners where customers require the benefits of reduced LRA. High inrush current (LRA) can cause light dimming and power interruptions to sensitive electronics. This inrush current also results in high torque and stress on HVAC compressors that can cause noisy starts. Also, for backup generator applications, HVAC compressor LRA can cause a significant strain on generators and high LRA ratings can require generators with higher kW capacities to start the HVAC systems.
  • Can SmoothStarter help reduce grid demand?
    Yes. SmoothStarter technology reduces inrush which has a significant impact on utility grids. A reduction in grid demand can also show savings on utility costs.
  • What is the difference between a SmoothStarter and a "hard start kit?"
    A "hard start kit" is a capacitor that provides a significant "voltage boost" to the compressor and also shortens the duration of the compressor start. They are designed to be a low-cost method to start compressors that could or do experience intermittent incidences of compressors not starting. The causes for these non-starts can vary widely. Although the duration of the start and LRA condition is shortened, the inrush current (LRA) is NOT reduced and actually could be slightly increased. SmoothStarter uses a programmed circuit board and start capacitor to measure the characteristics of a motor and then optimizes electrical input over several start cycles until the starting inrush current, or Locked Rotor Amp (LRA) is significantly reduced.
  • What HVAC system compressor LRA reductions should I see when SmoothStarter is installed?
    With proper model selection and installation, as well as proper incoming power supply to the HVAC system SmoothStarter will reduce LRA by 60%; or LRA will be reduced to 40% of the rated LRA. To translate this into actual LRA, simply multiply the LRA listed on the system name-plate by (.4). Example: LRA: 132 x .4 = 53 LRA
  • How do I determine if SmoothStarter will work on my HVAC system and if so, what model should I select?
    There are two (2) SmoothStarter models available for HVAC applications. First, review the specification information to note the model nomenclature descriptions. Then, review the HVAC system “name-plate” to match voltage, HZ, and compressor Run Load Amps (RLA) with the proper model. *You may also use the Selection Guide for HVAC Systems. This guide will outline easy steps to follow in selecting the proper SmoothStarter model for your system.
  • Can SmoothStarter be installed on HVAC systems that use reciprocating or rotary compressors?
    Yes; as long as the refrigerant system equalizes within 5 minutes of the system shut down. Licensed HVAC contractors can determine this by using refrigerant system pressure gauges and following proper procedures in attaching and reading them. When proper refrigerant system equalization is verified, normal application steps can be followed to select the proper SmoothStarter model. *You may also use the Selection Guide for HVAC Systems. This guide will outline easy steps to follow in selecting the proper SmoothStarter model for your system.
  • Can SmoothStarter be installed on HVAC systems with variable speed or "inverter-driven compressors?"
    Variable speed and similar compressors do not experience dramatically increased LRA that single/two stage compressors do. Therefore, a smooth starter should not be required and SmoothStarter should not be installed.
  • Are there any other benefits to my customers that SmoothStarter provides?
    Yes! The most easily identified benefit is likely elimination or significant reduction in "dimming lights" when the HVAC system starts up. HVAC system LRA can be 5-7 times greater than RLA and this inrush current is the cause of "light dimming." Homes in rural areas and in older neighborhoods are particularly sensitive to such challenges due to electrical grid limitations. Such dramatic LRA reduction will also reduce compressor torque that can cause noisy compressor starts. When compressors start, there is significant shock as the motor and compression components ramp to full speed in under a second! A "smooth start" reduces this "shock" and promotes quieter starts and reduced stress on the compressor. There are other features included with SmoothStarter operation such as low voltage starting protection and post power-interruption restart delays.
  • Is SmoothStarter easy to install?
    Yes. SmoothStarter should take ~15 minutes to properly mount and connect inside the HVAC system control/electrical service compartment. Wiring leads necessary for a normal HVAC system installation and unit mounting bracket are included. Installation Instructions are included with SmoothStarter models and all steps should be followed for proper installation and operations. *All electrical power should be DISCONNECTED before beginning installation procedures.
  • How do I verify SmoothStarter is performing as stated?
    To verify LRA reduction in a field installation, technicians will require a device that can capture inrush current and display this LRA value in a digital readout. FLUKE® 375 Clamp Meter is one such tool that is available for field use. Although not as accurate as an oscilloscope (which is required to test and rate LRA for compressors), this device should allow field technicians to verify SmoothStarter performance when used properly. ​ The LED portal on the front cover of SmoothStarter can also be used to verify operation. A steady, non-flashing light indicates SmoothStarter is wired and operating properly. If the LED light is flashing, this indicates a "fault" condition. Please review Installation Instructions, Specification Documents, or Submittal Sets to determine the fault codes.
  • Can I apply SmoothStarter to well pumps or other applications?
    Although no significant testing has been done, well pump applications have had SmoothStarter applied successfully. Please review the requirements for reciprocating/rotary compressors as they pertain to starting "under a load." SmoothStarter is designed to start direct, across-the-line motor starts that have ZERO load applied on the motor shaft. If there is a load on the compressor or pump motor at startup, SmoothStarter should not be applied. Compressor motor RLA considerations are also necessary to verify potential operation. SmoothStarter should not be applied to "squirrel-cage" or other types of fans. SmoothStarter is an electrical device and should be mounted in a protected compartment.
  • What is the warranty for SmoothStarter?
    SmoothStarter limited warranty is 1 year from date of installation.
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