--- product_id: 2331469 title: "SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque" brand: "sealed unit parts co., inc." price: "€ 50.00" currency: EUR in_stock: true reviews_count: 10 category: "Supco" url: https://www.desertcart.at/products/2331469-supco-spp6-relay-capacitor-hard-start-kit-with-500-increase store_origin: AT region: Austria --- # 500% starting torque boost Universal PSC A/C & heat pump fit Plug & play relay integration SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque **Brand:** sealed unit parts co., inc. **Price:** € 50.00 **Availability:** ✅ In Stock ## Summary > ⚡ Start Strong, Stay Cool — Power Your Comfort Like a Pro! ## Quick Answers - **What is this?** SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque by sealed unit parts co., inc. - **How much does it cost?** € 50.00 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.at](https://www.desertcart.at/products/2331469-supco-spp6-relay-capacitor-hard-start-kit-with-500-increase) ## Best For - sealed unit parts co., inc. enthusiasts ## Why This Product - Trusted sealed unit parts co., inc. brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Power Up Instantly:** Experience a staggering 500% increase in compressor starting torque for effortless A/C startups. - • **Smart Relay Protection:** Integrated relay disconnects the capacitor post-start to safeguard your compressor motor. - • **Versatile Compatibility:** Designed specifically for permanent split capacitor single-phase A/C and heat pump systems—residential or commercial. - • **DIY Friendly Installation:** Quick 10-minute install for savvy professionals with clear wiring and mounting instructions. - • **Energy & Generator Friendly:** Reduces startup strain on generators, letting you run your A/C smoothly even on portable power. ## Overview The SUPCO SPP6 Hard Start Kit delivers a massive 500% boost in compressor starting torque, engineered for permanent split capacitor single-phase A/C and heat pump systems. Featuring an integrated relay to protect your compressor motor, it’s a cost-effective upgrade that reduces startup strain, especially beneficial for generator-powered setups. Easy to install and compatible with residential and commercial units, this kit transforms your cooling experience with reliable, efficient starts every time. ## Description Relay/CAPACITOR hard start kit 500% incr starting torque,increased compressor starting torque. Designed for use on permanent split CAPACITOR single phase a/c and heat pump systems. Multiple use includes: room air conditioner units, residential or commercial psc AC units.. the country of origin is china. Review: Worked for me - Bought this capacitor not expecting much - cause its so cheap. Did not take long to get it, thanks desertcart! Bought a cheapo Generator (All Power America APG3012 3,250 Watt 6.5 HP OHV 4-Cycle Gas Powered Portable Generator - search for it on desertcart ) - and found that it could not start my RV/AC without some hysterics - literally the generator started to walk across the driveway trying to rev up enough to start the compressor on the A/C. IT would eventually kick in, but I wanted a better solution. Took about 15 minutes to put this capacitor on my 2002 Dometic 13.5K BTU A/C. Which did have a starting capacitor - bout 1/2 the size of this thing. I just wired it in parallel as there were lugs to do so on the original starting capacitor. And sure enough! The A/C compressor started, the Generator surged just a bit under the strain, then returned to normal speed - I base this on how it sounds - dont have a A/C volt meter. But worked very very well. I've run this combo for several hours to test the capacitor and the generator - no real issues other than if i run the A/C i can’t run really any other high amp device such as a microwave, but hey I didn't want to lug around a really heavy generator for camping and having some A/C while in the desert is fantastic. I should mention, that the Generator can start the A/C when it’s first turned on, but when the system pressurizes - that’s when the generator could not re-start the compressor easily. Now if there is at least 45 second between compressor cycles, this capacitor makes the next start of the compressor pretty painless without much struggle by the generator. I was told by someone that works on A/Cs that when the system is pressurized the compressor takes more power to start. For what its worth. Review: Straightforward Install for Skilled Persons - This was a 10 min install, but you need to savvy and comfortable working on electrical items, especially capacitors. There are You Tube videos that are constructive. After opening the nearby circuit breaker, opening up the electrical cover, grounding out the capacitor(s), and mounting/connecting the Hard Start kit, the kit performed as advertised. The AC compressor started up more easily and isn’t as loud at startup. This particular HS kit has an integrated Relay to disconnect its internal capacitor to prevent damage to the compressor motor after startup. Other comparable professional two wire or three wire HS kits cost about $150. My AC vendor offered to install their HS kit for $389, ## Features - Relay/capacitor hard start kit 500% incr starting torque - Increased compressor starting torque. Designed for use on permanent split capacitor single phase a/C and heat pump systems - The country of origin is china ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0002YTLFE | | Best Sellers Rank | #13,714 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #50 in Industrial Electrical Capacitors | | Brand Name | Sealed Unit Parts Co., Inc. | | Customer Reviews | 4.6 4.6 out of 5 stars (1,962) | | Global Trade Identification Number | 00687152197361 | | Included Components | Electrical Replacement Parts^Electrical Replacement Parts^replacement-household-furnace-control-circuit-boards | | Item Dimensions W x H | 6.5"W x 7.25"H | | Item Shape | Round | | Item Type Name | Relay/Capacitor Hard Start Kit 500% Incr Starting Torque - 661389 | | Item Weight | 0.3 Pounds | | Manufacturer | SUPCO | | Material Type | Copper | | Mounting Type | Panel Mount or Surface Mount | | UPC | 687152031528 687152197361 | | Unit Count | 1.0 Count | ## Product Details - **Brand:** Sealed Unit Parts Co., Inc. - **Material:** Copper - **Mounting Type:** Panel Mount or Surface Mount - **Product Dimensions:** 6.5"W x 7.25"H - **Shape:** Round ## Images ![SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque - Image 1](https://m.media-amazon.com/images/I/71wgg5wU+zL.jpg) ## Questions & Answers **Q: I live in Az.I need a hard start kit for a 30,000 btu 2.5 ton,which one do you recommend?** A: The Supco uses a Positive Temperature Coefficient Relay (as stated on their website) not a Potential Relay. Not Good! Only use Hard Start Kits that use a true Potential Relay. The RectorSeal Kickstart (2 wire) and the 5-2-1 Compressor Saver (3 wire) hard start kits use a Potential Relay. I recommend the Kickstart (it uses 2 wires that connect to the Run Capacitor - HERM and COM). But the Compressor Saver is also good (3 wires with one connecting to the common / ground on the Contactor relay). They both work the same way - the Potential Relay detects the pickup voltage (back EMF). This causes the relay to disconnect the start capacitor when the compressor reaches about 75% speed (usually less than a second). Note: Supco does have hard start kits with a Mechanical Potential Relay (Models 3W1, 3W2, & 3W3) but they are not available on Amazon. **Q: If there is an existing start capacitor, can you put this one in parallel with it or the run capacitor?** A: This takes the place of the start capacitor. It gives an old compressor a "punch" as it starts and it immediately goes out of the start up circuit. They work! It is wired in parallel with the run capacitor, which stays in teh circuit so your compressor will run more efficiently..electrically speaking. **Q: Can a hard start kit help an a/c compressor start when powered by a generator which more than satisfies the unit's FLA but is just shy of the LRA?** A: Greetings,I use these for my rental apartment AC units they keep these old units running and starting easy! They need to be checked every 2 year or so. If you are just shy of the Locked Rotor Amperage; The amperage the motor draws when the voltage is first applied to the motor and the rotor has not started to turn. This amperage is usually up to 300% of the motors running amperage. Once the rotor starts to turn the motor generates a back EMF (electro motive force) that opposes the high inrush current. This back EMF drives the amperage down until the motor gets up to its rated speed at which time the motor amperage will be at its run amperage. This device helps starting and should make you successful. Make sure that your line voltage is being properly supplied during the high current peak that you have proper AWG for the load and length from your generator to your compressor as it could be a voltage drop issue.Never the less a good part and should help.Best of LuckDarrell **Q: Is this pretty easy to install? Is it just removing two wires from the old capacitor and reattaching to the new hard start capacitor? Thanks.** A: The hard start cap installs in parallel with the old cap. You connect one wire to the common and one wire to the herm terminals on the old cap. This just gives the compressor an extra kick. I would recommend that you get the 5-2-1 hard start kit instead. I have tried both and the 5-2-1 works better. Just search on Amazon for 5-2-1 hard start kit. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Worked for me *by P***N on June 15, 2015* Bought this capacitor not expecting much - cause its so cheap. Did not take long to get it, thanks Amazon! Bought a cheapo Generator (All Power America APG3012 3,250 Watt 6.5 HP OHV 4-Cycle Gas Powered Portable Generator - search for it on Amazon ) - and found that it could not start my RV/AC without some hysterics - literally the generator started to walk across the driveway trying to rev up enough to start the compressor on the A/C. IT would eventually kick in, but I wanted a better solution. Took about 15 minutes to put this capacitor on my 2002 Dometic 13.5K BTU A/C. Which did have a starting capacitor - bout 1/2 the size of this thing. I just wired it in parallel as there were lugs to do so on the original starting capacitor. And sure enough! The A/C compressor started, the Generator surged just a bit under the strain, then returned to normal speed - I base this on how it sounds - dont have a A/C volt meter. But worked very very well. I've run this combo for several hours to test the capacitor and the generator - no real issues other than if i run the A/C i can’t run really any other high amp device such as a microwave, but hey I didn't want to lug around a really heavy generator for camping and having some A/C while in the desert is fantastic. I should mention, that the Generator can start the A/C when it’s first turned on, but when the system pressurizes - that’s when the generator could not re-start the compressor easily. Now if there is at least 45 second between compressor cycles, this capacitor makes the next start of the compressor pretty painless without much struggle by the generator. I was told by someone that works on A/Cs that when the system is pressurized the compressor takes more power to start. For what its worth. ### ⭐⭐⭐⭐⭐ Straightforward Install for Skilled Persons *by A***R on July 17, 2025* This was a 10 min install, but you need to savvy and comfortable working on electrical items, especially capacitors. There are You Tube videos that are constructive. After opening the nearby circuit breaker, opening up the electrical cover, grounding out the capacitor(s), and mounting/connecting the Hard Start kit, the kit performed as advertised. The AC compressor started up more easily and isn’t as loud at startup. This particular HS kit has an integrated Relay to disconnect its internal capacitor to prevent damage to the compressor motor after startup. Other comparable professional two wire or three wire HS kits cost about $150. My AC vendor offered to install their HS kit for $389, ### ⭐⭐⭐⭐⭐ Helps our 2.5 ton, a ton *by A***A on March 13, 2025* I bought this a year ago to keep as a spare and recently since I was cleaning our 2.5 ton Goodman condenser I decided to just install it since everything was taken apart already. It's a simple install, just bolt the CAP to the unit next to the existing one, and then for our unit, connect it to the red and yellow terminals on the existing CAP. After reassembly, the first thing I noticed is that the condenser kicks on instantly now, before it would have a ramp-up of 15-20 seconds where it would slowly start up before getting to full speed. Now, that happens immediately. Highly recommend installing one of these. ## Frequently Bought Together - SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque - VEXUNGA 45/5 uF 45+5 MFD 370V or 440V Dual Run Start Round A/C Capacitor 45 5 uF 370 440 Volt VAC CBB65B Air Conditioner Capacitors for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool - TITAN PRO, 1 Count (Pack of 1), No Color Packard TRCFD455 45+5MFD 440/370V Round Run Capacitor Replaces PRCFD455 --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.at/products/2331469-supco-spp6-relay-capacitor-hard-start-kit-with-500-increase](https://www.desertcart.at/products/2331469-supco-spp6-relay-capacitor-hard-start-kit-with-500-increase) --- *Product available on Desertcart Austria* *Store origin: AT* *Last updated: 2026-04-23*