Does the hard start kit make the modern A/C work better?

[Music] okay this one's about whether you should put a hard start kit on the modern air conditioner most of these come with a run cap and the Run cap also is a start assist to get the compressor running uh if I add a hard start kit I'm adding a larger size capacitor uh to give that thing quote a kick to get it started is that worth it is that something that's valuable okay we'll take a look at this air conditioner to start with this is about 10 years old uh it uses a TXV a non-bleed TXV which used to be the reason we put hard starts on was if we had a non-bleed TXV the pressures would not equalize in the off cycle when the thing shut down the pressures would not equalize that meant the compressor had to start against a head okay this one does not have a hardar kit and it has a non-bleed TXV so why does it have that why why didn't they put a hard start kit on it well it uses a scroll compressor now almost everything out here use the scroll compressor anymore uh virtually all residential on the Loft a lot of commercial are using these Scrolls uh they've been out a long time they're working fine so a scroll is a different design than a piston compressor so I'm going to go ahead and take a look at an air compressor and let's let's look at what it does is and how it works and maybe we can get an idea of whether this makes any sense I'll also uh I've got a scroll out there that I can kind of do some limited demonstration with and we'll see if we can figure this out now here is a air compressor for a shop it's not that much different from a compressor use in refrigeration but this one this one's for uh supplying highpressure air to the shop now we have about 100 lbs of pressure in this thing right now and this is the motor this is the compressor now when this motor goes to start it has to push against that 100 lb of pressure that's in the tank uh it takes a lot of torque to get that thing to start if you'll notice right here on the motor there are three start capacitors on this big ugly start caps it takes a bunch of high torque to get this thing to start this is how piston compressors sometimes were in refrigeration systems the difference now and that start against that head was the reason for hard starts put into Refrigeration compressors uh if you had something like a non-bleed TXV which essentially meant that the high pressure that like you would see here more or less stays in the system and when this thing goes to push these Pistons up then it has to work against that head pressure uh if you had a uh fixed orifice metering device or a bleeding TXV they would equalize new off cycle so that these suction pressure and the head pressure would be more or less the same when they started but if they you had like a non-bleed TXV or some such thing that kept that pressure up high you need a hard start to make this thing make the refrigeration compressor start just like you need a hard start here cuz that's what that is okay here we're looking at a scroll compressor now this one this is actually a pretty good size compressor I think this one was four or five tons just an old dusty thing I had floating around here these two Scrolls fit together like that and what this does when you start it the motor shaft is right here and it's on an eccentric it just starts going like that and I'm not going to try to explain everything inside the scroll because that's another another video when these shut off there isn't any real pressurized gas in here uh there's no high side uh and low side that are affected this thing pretty much equalizes right off the bat and even if it didn't equalize it would still start quite easily without any start components other than the Run cap manufacturers this is a Copeland here manufacturers generally do not specify hard start kits on their machines there are cases where they do and they do Supply hard start start kits for those applications but mostly in an air conditioner if you're you're saying well I want my air conditioner to run longer and you know start easier and use less power a start kit is not going to make any difference for that that's not what it's for and negative things about start kits I'm just using a fan motor here here this is your rotor and then here's your windings now when this rotor starts to rotate when you first put power to it it's kind of like the the kid in the uh wagon he's standing in the back of the wagon decides to jump out the back of the wagon and falls on his face cuz the wagon moved when he pushed off with his feet the wagons just start rolling off okay that's the same thing that happens in here when this thing starts to turn this way the stator wants to turn back this way has an equal and opposite reaction backwards that means these windings are put in tension because the mag magnetism is in the windings it's concentrated by the field but it's in the windings and they jerk a little bit if I put a hard start kit in they jerk a lot more it hits them hard cuz these things they have to start against some some sort of load so it'll start faster it will not remain in start mode for very long it's very short kicks off right away uh faster than just using the uh run cap but it hits those windings harder are the windings made to stand that yes they are this fan mot they aren't but in the compressor they definitely are they're made to withstand that and they will withstand stand it but it is not as good on the compressor as using just the Run cap it's kind of like your car if you come to a stop sign and floorboard the accelerator that's puts a lot more load on the components in the car than if you move off slowly uh and that's probably the closest analogy I can come up with uh for what happens with the start kit it hits it hard and they can they can hit really hard okay next we're going to do a couple of tests with this unit I'm going to test it with just the capacitor uh run the run capacitor starting it and with a hard start kit and we will look at the difference and see what we see uh the claims are less heating of the windings in the compressor because when it starts it starts at locked rotor and then as it starts to rotate the back EMF starts uh reducing the amp draw but there is supposedly more amp draw for a longer period of time without the start kit now ideally that the idea there is the compressor would last longer U because of less heat build up it also uh is claimed that the compressor under less load on Startup now that one uh yeah that may be a problem but we'll see we'll see what happens here now we're going to use a uh meter that will read Peak load Peak amperage and I have to kind of modify this a little bit this is a meter that will read the the peak but but none of these meters are actually really good at this it takes some real life equipment to do that right uh this will be a comparative analysis only because this is not going to read the maximum amp draw it's just not accurate enough to do that but because I can use it as a comparison uh it may be useful to us the first thing we're first one we're going to try is with just the Run cap as a starting device okay 49.1 two okay now we're going to test it with the hard start kit on it okay so you can see there's considerably less amp draw when you have the hard start kit on it the issue here though is how long did the start circuit operate now we know that if we put a start kit on it with a large cap that's going to divert a lot of the power to the start winding it's going to put more power through the start winding than if it just starts with the Run cap so it's it's shoving more power to the uh the start winding uh as opposed to putting it to the Run winding so what are the conclusions of this whole thing it took one3 the amp draw for the start with the uh start cap with just the Run cap it took uh more anach for a longer period of time now the time period is best I could come up with was about 1/1 of a second for the uh hard start kit and it was about 3/10 of a second for the uh for the Run cap so it's different okay one thing that I should throw in here the hard start obviously hits harder than and with the with the problems I've talked about with having them hit harder but it's also increasing it actually about doubles the amp draw through the start winding I was running around 5 amps through the start winding and with the hard start I was running about 11 it's putting more load on a lighter winding the start winding is much lighter than the Run winding it's not made to be at full usage for any length of time it is controlled by the Run cap the Run cap limits the uh amperage that goes through it but when you use a hard start kit it just throws a whole bunch of power to it and that that's what gives it the kick would I put a hard start kit in something that didn't need a hard start you know it was just a unit that I had that was working fine doing everything fine no I think it's probably easier on the compressor to have that it's not a soft St I keep want to say it's a soft St it's not a soft start but it's a it's a run cap start uh another thing was heat buildup well there's so much heat buildup because it takes longer to start it's 310 of a second guys I did the numbers on that silly thing and using the capacitor start we used about 150 watt to start the compression uh that don't mean nothing you're really doesn't mean hardly anything at all it's not going to build up heat in the winding and if it is building up heat it's building up more heat in the winding that's made to handle it and that's the Run winding so I don't think any of that's true uh if you have compressor problems or something like that there you can put hard starts on it all all day I've done it many many times to tell a person I'm going to give you two weeks or two years and I don't know which one it's going to be and as soon as I leave the place you're on your own because usually what you're doing when you have a hard starting compressor that has a good run cap you need to know about that that has a good run cap if you have a compressor that won't start sometimes both fuses or something like that it's just getting worn out you can maybe get it a little longer I've had them last as long as a couple years but to put a hard start kit on a system that's working beautifully you're not going to uh in my opinion you're not going to get any longer life out of the compressor or anything like that it is not easier on the compressor it's either about the same load on the compressor or maybe a little more okay that's it on this one

Channel: grayfurnaceman

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Id: 2gDMD1vaew8

Length: 15min 9sec (909 seconds)

Published: Wed Jul 17 2024