How and when to consider replacing an ac contactor and some of the factors involved in the diagnosis of an air conditioning contactor.
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and find our handy calculators at https://www.hvacrschool.com/
Hey this video is from our technician, Burt and he's talking through the replacement of a contactor, and so there's two reasons to consider replacing a contactor one is: is that that voltage drop can drop the voltage to the compressor, which, of course reduces the system's capacity efficiency? All that and you need to have the rated voltage applied, but then also when that contactor starts to overheat, it's more likely that either it will fail open. So it doesn't allow the system to run or it will fail fused, which means that it runs all the time. Potentially. This is especially important on three-phase contactors.
So if you're working on commercial units with three-phase contactors, you need to take very seriously inspecting those contactors and replacing them when they begin to fail, because in three-phase, if you only have one contact, that's not making contact that will create something called single phasing which can Quickly burn up a compressor in single phase, which is what we're looking at here in residential, it's not as big of a deal. But it is something that I suggest when it gets to the point that Burt shows here in the video that we at least talk about it with the customer and let them make the decision of whether or not they want to replace it. A lot of people will see this as a like an upsell sales tactic, or something like that. I don't advocate doing it that way, no high-pressure sales, just simply showing it to the customer and letting them decide when it gets to about the point that Burt shows here.
It's really the one he's showing here pretty much right on the line of where we would suggest it to the customer is something they may want to go ahead and address. He does a nice video here showing what to kind of think about when you replace it and some of his little quick tips, some of them. You may like some of you may not, but I want to kind of address them as we go along. So here's Burt with his apprentice, Kerby, hey guys it's Kirby and I and we're doing a maintenance.
We ran into a problem pretty common. Go ahead. Show here the contactor. Take a look at that.
Does it look like Kirby? It looks black so pretty common problem, but it's really important on a maintenance to actually be inspecting things like this details like this, like the contactor showing what you had to pull off. So this cover right here, so you can see it's not really any way of knowing that that's going on that we have a problem just about to happen. Unless you open that up that extra step, take a look, we brought the customer out talk to him about this, show them that there's a visual thing about the importance of it here to take a look at the new one which fold the cover off. So you can see, look at the difference there lift it up.
So you can see the connection points a clean. Those pads are and that's where all of our voltage to our compressor and fan motor pastor. So we've already turned off a breaker out here. So Kirby's not getting shocked right now. They've already turned off a breaker inside because there's low voltage on on each side of this coil and another thing you can do if you're not inside by the breaker, is pull this plug on the defrost board. And you don't have any will voltage fuse unnecessarily before you start this process check if you have a wiring diagram still available on the panel, if not take pictures either way. Take pictures save yourself the trouble of tripping the breaker or shorting out a compressor. So I pulled this contactors.
You can see a part a little bit here, taking the pads off and you can see the texture on there how those pads are starting to get tore up, and that happens every time it arcs. So it pulls in and is actually an arc and the worst connection it has on contact. The stronger is going to arc and it gets so hot. It literally starts melting and that's what you're seeing right there and that's where the pitting is coming from, and the black all around just shows you how much it's been arcing now.
This was running without any problem, but it wasn't gon na be long before we start having problems and the potential for problems is actually really big. You can get a failed compressor just from having a contactor that either pits and actually melts in place. So this pad right here will melt onto this pad and your contactor is forced in it doesn't ever shut off. The other problem is, is that when these pull in, that is when your compressor is at pulling the strongest amount of current? So, let's look at this data tag here: locked rotor, amps, 158, every time that compressor stuns it's in the position of a lock, rotor amps, and all that current has to come through here pass through these two points through these pads.
So the moment it pulls in it starts that at surge of current and for the next couple seconds, there's a lot higher current than the normal run current through those pads. That's why it's important that that connection is clean and your voltage can pass cleanly through there. Every once in a while, you'll have it to where it's pulling in, but there's just a slight voltage up and you will cause a compressor fail it that way too. So we need to put these wires right and put the different type of yes.
We do yeah yeah. Let me go ahead and show what I do there right here. So I'm gon na cut off the end that now, specifically, you see he cuts those ends off. Some of you are gon na gripe about that, but, frankly, I've done that very same thing.
Many many times in the field and yes, there is a copper and potentially a steel connection there, but there is anyway right. I mean if you leave the Spade connected under a screw. You still have that same sort of connection, and so I'm totally okay with him doing that. I've done it for many many years.
We're gon na take this right here and actually stick it down in there and we'll put a little electric crease on there and clamp down on to that which is a little bit of a better connection than actually clamping onto the wires and smashing down on the Copper, you can see how thin these braided wires are. So I like, using this a little bit better. It's just kind of a quick way of making this a better connection. So Kirby's got it right here. The contactor before we put any of the wiring in so now comes the part that Kirby you're gon na do this by memory. She tells me he's not gon na get it wrong. Sorry, electrical grease this connector yeah there you go all done, Oh inspection. Now I want to specifically address he put some electric grease on here and I was I was torn.
It was. It was one of these things where I thought about just editing it out where he put the electric grease on, because I know that a lot of people will have a problem with that and the reason they'll have a problem with. It is because they kind of should have a problem with it. Some people will say it's dielectric grease.
That means that it doesn't conduct, and while that is true, the design of dielectric grease, or in this case it looks like he used no locks, which is specifically designed as an anti corrosive for connections between aluminum and copper. It's designed to help prevent corrosion, and so it will help on that side. But potentially, if you don't get it snug down, you may not make as great of a connection under there. It's something that technicians do every day out in the field.
I've already instructed Burt not to do that anymore because it isn't, it isn't really the designed application for it. But frankly, it's not gon na hurt anything as long as you are getting a nice snug connection in between and when you read the spec sheets on these. It really is sort of a complicated topic. It's not it's not straightforward as far as if it's a good thing or if it's a bad thing in cases like this, especially when you're dealing with lower voltages, it gets more risky, because now you have more potential for for voltage drop to be an issue in This case, I decided to show it just to address it again.
Look at the listing and labeling instructions of anything that you're gon na put on anything. And if you were to look at the data tag on no locks, you would see that it's specifically designed as an anti-corrosive for connections in between aluminum and copper, and because of that I mean really, it couldn't cause a problem. I I doubt it if it's designed to be put on those connections, I'm sure it's not gon na cause a problem where it's connected inside this contactor, but it's just something that I'm not gon na suggest that we do moving forward. But for the sake of authenticity, we left it in the video all done inspection.
This symbol right here is for an open switch right here. So both sides of these are open normally when they get the voltage they close and then out the top of each of that. You have your wires, the colors and what motors or function they're going towards, and so that's what you need to look at. So we'll start with our low voltage. What do we have coming off of our coil? Here's, your coil! We have blue and blue right on to that side. The black over here confirm that yep coil and that's what you do just goes to that process. Now, when there's been like motor replacement, compressor replacement, your colors are gon na, be the same, but they're always going to go to the same motor, and you can see here. Here's your compressor, here's your fan and the colors coming off of that down to here the capacitor where's that wire being connected to what color is that great good looks good, yeah, confident we can turn this on yeah this, let's go ahead and put this cover on Help you help keep the ants out.
It's just just a little safer when the power is off Mary Kirby's, pretty sure that he's ready. Are you ready couple? Other things I would have liked him to show is actually testing the meter to a known voltage source and actually checking to make sure that there is no voltage rather than trusting a disconnect, isn't show what he did there. But that's something that I want to make sure that we do as part of the electrical test procedure and then, in addition to that, checking that voltage drop across the contacts before and after as well as applied voltage before and after under load. So it acts that has to actually be running.
The other thing is when you flip a breaker on, I always want to see an amp clamp on that compressor lead. So that way you can monitor it. As that compressor comes on, I like what he suggested as far as taking pictures. So that way you make sure that you wired up properly and also he showed it snug down.
Well, he used a good insulated screwdriver there, which is wise. But if you were gon na be really technically correct, you would use a Torx screwdriver. I know it's one of those things that almost nobody's going to do in residential, but it's just worth mentioning and that contactor does have a torque spec on it, and so you could torque it down to the inch pounds that that particular lug was designed. For that.
Would be a little bit more technically correct, so a lot of things that I have to kind of mention there, but in general I'm a fan of authenticity and learning as we as we go and getting better and our practices as we move forward. So I think this is a teachable moment for for all of us, and hopefully you learn something in the video thanks for watching.
What the hell is electric grease lol
I read the title too fast, I thought it said when to change a "contractor" and first few seconds of the video was very confusing haha. Service area Nepean??
You have exceeded your "SO" & "HERE" quotas for the day!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I would like to see a video if some team members telling about the biggest mistakes that they've made. Are you in Barrhaven ?
Dielectric grease is non conductive this is not the appropriate use .They make the proper grease for that application manufacturered by several suppliers but let's be clear that is absolutely the wrong use of the grease the tech used and all screws on high amp connections should be torqued to stated value on the contractor
I’ve been using the same method of leaving the crimp on when changing out contactors for a few years. Now we only stock lug type contactors because of the solid connection the is method provides. Your narration is spot on. Great video.
Very detailed I wish I had the benefit of training like this when I learned the trade many years ago .
When dealing with a three phase system and three pole contactors, is there a way to test the Integrity of the contacts and determine when they are close to failure?
I've been doing electrical since the early 80's and I had some systems that I performed 6mo maintenance on for years on end. I've seen new systems go in without the use of deoxidizing compounds and end up with terminal corrosion in 2-3yrs. Then I've monitored connections that have been treated with De-Ox, Noalox, etc. and seen zero issues. I alway do voltage drop tests and measure terminal temperature, and the De-Ox/Noalox treated connections have performed significantly better than untreated systems.
I use de-ox compounds on on all connections that are outdoors or in high humidity areas, with excellent results. I even go as far as using de-ox compounds on male cord ends, plugging them into recepticals in order to coat those contact areas. I am 100% convinced that the de-ox compounds are benifical, if used in moderation. Regardless, always tighten, wiggle, tighten, wiggle, tighten, wiggle, tighten wiggle…
True, the contacts are pitted, but they didn't do a voltage drop test or measure temperature.
I truly believe some of the original equipment contactors are undersize and cheap. Sometimes it’s better to go up a size. Also it should be verified that the unit is not able to short cycle, or try to start when the system isn’t yet equalized. Frequent starts kill contactors.
One thing I've found that is also very important when replacing contactors is referring to the schematic as was done here to confirm the style of contactor. We run behind a lot of people working for home warranty companies and often I find double pole contactors installed (without properly jumping out the proper side of the contactor) where a single pole contactor was originally intended by the manufacturer.
Has anyone used this? "DEOXIT Contact Cleaner" that is how you properly clean and protect contacts like the lugs that were greased. This product and products like it are designed for that.
Fantastic Video. I for one appreciate transparency and you nailed it!
How come HVAC companies are crazy about technology, but won’t use a voltage zero crossover circuit to only energize the contactor when the
AC mains are about to cross zero volts on the sign wave, thus drastically reducing the arcing.
commercial videos, residential is like a shady tree mechanic
had one being shorted by a 24 volt short in the furnace blowing the 3 amp fuse on the board. Fixed the rub out short. Called for cooling and the contacter was chattering. compressor sounded horrible. Shut system down changed contacter and restarted compressor. Compressor would not run and was off on thermal. Placed ice bag on top and went to lunch returned and attempted to restart compressor. would not restart. Omhed out single phase compressor one omh per leg. Advised customer compressor went bad.
Definitely check for no voltage I have personally bit because someone bypassed one leg in the disconnect.
Love watching the videos. After 35 years in the trade and 69 years old I had to give up the trade that I loved. Every once in a while I have to work on one of the package units at my church and feel 30 years younger,
I fucking love these videos with this guy hahahaha hella funny 😂
I have been coming across a lot of buzzing contactors in electric heaters (208 3phase with 208v coil) they are pitted pretty good too, when I swap them with new ones they dont buzz. What causes this? Thanks!!
Love the honesty in this video, and I learned from it.
Oh I thought u said contractor!?
Switch!!!
Like musical chairs!!!
The one with plumbers crack syndrome goes 1st!
Pull ya pants up before you come to my place….. ain't nobody got time for that😂🤠🤣
I change them when they have sutty look around the contact area! Or intermittent strange freeze ups!?(or visibly worn!!)
Always put right size in too(residential)or slightly higher amperage (30amps are good!)RFL ?!
Bigger the unit single phase unit… probably need a bigger contactor amperage 30-40 plus?!
Wire terminals burning wearing…. replace contacts & make sure they're tight snug fittings!
Clean /rinse the condenser coil…. hot unit …. hot/ harder working outdoor unit/system!
Take it to da house 🏡🏃🏼
There's always more to check…
Experience will tell you if low on refrigeratant after cleaning coil(s)… take temp drops at supply & return vents etc!!
A history of good check ups will help with determining the system charge!?
Eliminate call backs! Do a gd thorough job the 1st time!!👍
Where do I get the “HVAC” hat?
I’m here because i want to be the best I can be. Thankful for your knowledge 👌 Service area Orleans??
I would have liked to have seen you mention the sizing of the replacement contactor with the appropriate FLA as the OEM part.. 👍
Bert & Kirby show!!!!!!
Nice 👍 👍
Being a little picky but 2 things. 1st use factory style contactor and you won't have to worry about the issue of the wire ends. 2nd ants will still get into that style of contactor…lol had it happen many of time…. Are you in Ottawa ?
i swear it said "when to replace your HVAC contractor" i replaced mine when they didn't respond to my emails lol.
Sound like yall the kind of guys that try and sale a complete system when a fan motor goes out. There was nothing wrong with that contactor
How much did you charge to replace the contactor? If you dont mind me asking. Just started my own business. Thanks
If the dielectric grease creeps in to the contacts of the contactor that would be really bad!
Some fuckery going on on that condenser coil! Are you in Kanata ?
Bryan made good points about measuring the voltage drop across each contact. This should be done before and after contactor replacement. From my checking of voltage drop,, 50 millivolts would be the maximum. Also, an amp clamp as mentioned would confirm the unit doesn’t have any hidden issues.
Dude wears his wedding band when handling electrical?…….. tough
BEST damn HVAC channel on Youtube. I have a 10 year old condenser and I am going out to check my contactor right now and see if there is a voltage drop. The part is cheap.
I might be totally wrong about this but I feel a lot better smashing the wire strands into the lug rather than tightening down on the remnants of a crimp on connector. The skin effect of AC power would lead me to believe that tightening down on a crimp connector would not have as much surface area in contact with the lug Service area Kanata??
locked rotor amps is what the amp draw would be if the compressor is locked up not at start up.
Hello Bryan ( notice I spelled correctly, ey ) , where can I email you for an important question regarding testing compressor windings , please ( I heard you giving your email address on a podcast but I can't remember which one !) Thank you very much , this problem is doing my head in !