Multi-Brand HVAC Hard Start Kit Parts — Models & Compatibility

Your AC compressor clicks but won't start? That humming sound followed by nothing? You're likely dealing with a weak start capacitor, and a hard start kit like the SPP5 can fix it without replacing the entire compressor. This universal kit works across Trane, Carrier, Lennox, Goodman, Rheem, and even some Whirlpool dryer models — making it one of the most versatile HVAC parts you can stock.

Is This the Right Part for Your Model?

The SPP5 hard start kit crosses multiple part numbers (TJSPP5, AP5648661, HS520, HS600, ERPP5), which means it's been the industry standard for years. Check your model number on the metal data plate — usually on the side of your outdoor condenser unit or inside the dryer door frame for appliance applications. If you see any of the compatible models listed below, this kit will work. The beauty of a hard start kit is that it's semi-universal: if your system uses a PSC (permanent split capacitor) compressor motor, this'll fit.

About This Replacement Part

A hard start kit — also called a start capacitor relay — gives your compressor the extra electrical push it needs during startup. Think of it like a turbocharger for those first critical seconds when the motor demands the most power. Over time, compressors lose some of their starting torque, especially in hot weather when refrigerant pressure is high. Instead of replacing a $1,200 compressor, you install a $15 hard start kit that reduces startup current by up to 50%. It mounts directly to the compressor terminals and includes both the relay and the start capacitor. The SPP5 is rated for residential systems up to 5 tons (60,000 BTU), covering everything from 1.5-ton mini-splits to large central AC units. If you're hearing that telltale hum-click-silence pattern, install this before you burn out the run capacitor or trip the breaker repeatedly.

Installation Overview

Turn off power at the breaker. Discharge the run capacitor with an insulated screwdriver (seriously — don't skip this). The kit mounts with two wires connecting to the compressor's start and run terminals, usually marked S and R. Most techs mount it right on the compressor body using the included bracket. Takes about 15 minutes once you've got the condenser panel off. If you've never worked with capacitors before, call a tech — stored voltage will ruin your day.

Compatible Models

This part works with the following models across multiple brands:

• 4TTB6061A (Trane)
• Y8806 (Lennox)
• BAYKSKT263 (Trane)
• MT4155SPS5 (Whirlpool)
• 38CKC036300 (Carrier)
• GSX130361 (Goodman)
• RA1436AJ1NA (Rheem)
• H4A636GKA100 (Heil)
• H4A636GKA100 (York)
• WED6200SW1 (Whirlpool)

Why Choose This Part?

At $14.99, it's the cheapest insurance policy you can buy for an aging compressor. The SPP5 replaces multiple OEM part numbers, which means manufacturers have been using this same design for decades — it works. You're not gambling on some aftermarket experiment; you're installing the same component HVAC techs have trusted since the '90s. Plus, it often fixes issues that get misdiagnosed as "bad compressor" — saving you hundreds in unnecessary replacements.