Enhanced Start-Up for AC Compressors
Designed to help conditioners start more smoothly, the 5-2-1 CSR-U2 Hard Start Kit provides an added boost during compressor activation. Ideal for systems that struggle on start-up or experience frequent hesitation, this kit offers a practical upgrade for users searching for an AC hard start kit, a CSR-U1/CSR-U2 option, or a 5-2-1 compressor saver solution.

When will you need order CSR-U1 Hard Start Kit?
- House lights flicker during AC start up
- Your AC unit is noisy during start up
- Your AC unit takes a while to start up
- You want to extend the life of your AC unit
- You want to reduce your home’s energy consumption
With 1–3 Ton AC Units
Engineered to a wide range of residential cooling systems, this kit applications that use 5-2-1 wiring (Common, Start, Run). Whether you're looking for a CSR-U1 match, a CSRU2 5-2-1 compressor saver, or a 521 hard start kit, this component is designed to align with standard compressor terminals for proper installation.

Boosted Starting Performance
The capacitor and switch combination helps the compressor start with greater torque, allowing faster and more stable activation during heavy load or low-voltage conditions. This makes it a dependable choice for customers needing a compressor hard start kit or a reinforced option often referenced for improved start force.

Pre-Wired for Simple Setup
The wires are clearly designated for ease of use: black to common, stripped lead to start, and red to run. This setup helps streamline installation for HVAC technicians or homeowners familiar with AC component .


MODEL NUMBER: 5-2-1 CSR-U2 Hard Start Capacitor Kit
BOOST AC SYSTEM START-UP: 5-2-1 Compressor Saver significantly reduces the amount of time your compressor is on high amp start-up. a powerful multi-layer starting capacitor and a switch to give your compressor the boost it needs to start up more quickly and power-efficiently.
FIT MODELS: This Hard Start Kit works on 1- to 3-ton AC Units. Remember that 5,2,1 = Common, Start, Run.
IMPORTANT SAFETY WARNING – PROPER INSTALLATION REQUIRED:This hard start capacitor kit must be installed correctly and according to the wiring diagram. Incorrect wiring, improper installation, or the product outside recommended conditions may cause capacitor failure or damage to the AC system. If you are unsure about installation, please message before installing – we’re always happy to help ensure safe and proper use.
EASY TO INSTALL: Our CSRU1 5-2-1 Compressor Saver has been pre-wired (see wiring diagram) for your convenience. The black wire will be connected to the common side if the compressor, the stripped wire will be connected to the start winding of the compressor, and the red wire will be connected to the run winding of the compressor.
100% PROTECTION: Enjoy reliable performance with our protection, ensuring that your product will always be covered for any defects or issues that may arise.