Hard and Soft Starters in the HVAC Industry – Which Is Right For You?
A “hard starter” reduces system start-up time by spiking the in-rush current. It’s used when the electrical current may need a boost to get the A/C system operating. It increases in-rush to the compressor and doesn’t provide any protective benefits.
A “soft starter” increases the efficiency and longevity of HVAC units and heat pumps. It reduces the in-rush current needed for compressors to start by 60%, thus minimizing potential damage to compressors from mechanical shock hard-starting current surges. Additionally, it reduces the required size of a generator needed to start the system by 60%.
Which type of starter is best for you?
Pros and Cons of Hard Starters:
Hard starter kits (a combination potential relay and start capacitor) are preferred in applications in which the system design requires high starting torque, or in small-sized applications (less than 1.5kW), in which reciprocating and rotary compressors must start against a pressure head and may require a device to increase the starting torque. Note that if the HVAC unit utilizes a scroll compressor, hard start kits aren’t generally needed.
Hard starters typically cost less than soft starters. However, the forcefulness of a hard start can cause compressor parts to deteriorate faster. Another con is the noise factor.
Because of their simplicity, hard starters work best when all operating conditions are “normal.” If or when something does go wrong, they can fail – AND damage the compressor winding, as well.
Pros and Cons of Soft Starters:
An electronic soft starter is designed to reduce the starting current of the compressor by actively controlling the current in both the run and start windings. Soft starters also offer built-in features to protect the compressor under atypical circumstances.
Soft starters are particularly well suited for off-grid generator or inverter-based HVAC applications where the limited capacity of source rating and cable impedances over vast distances can imply that the compressor won’t start.
While soft starters cost more, they’re quieter and last longer, and the return on investment is realized several times over through generator savings and increased compressor life.
Introducing BriskHeat’s Newest Soft Starter – Surestart:
BriskHeat’s Surestart compressor soft starter protects A/C compressors from failures including stalling, overheating, motor reversal and arcing damage. Developed for use with single-phase scroll type compressors, the starters are available for all standard size compressors up to 32A and voltages up to 230VAC.