Dave - it's great to see you up and about with your usual very useful vids! Keep 'em coming. Greetings from New Jersey.

strange how A/C caps can go bad and not bulge . While they do in other devices ! ENJOYED, Great work

I have 2 Rheem central A/C units, a 2 ton and a 4 ton. I never did have trouble with them starting, but did a bit of research into the hard start kits. I ended up buying 2 kits (different ones, for the different units) from Rectorseal. I installed them and could not be happier. Before the hard start kits, when either unit would start, the lights would noticeably dim in the house while the compressor was in the start winding.. After the installation, I still get the lights dimming because of the huge inrush of current, but it's for a much shorter duration, and they don't dim anywhere near as much. A hard start kit will complicate matters slightly in the event something like this happens again, as it could be the actual split capacitor OR the hard start kit. That is to say, if the hard start kit were to fail yet the split capacitor is good, the compressor will not start. So in the future, should this happen again, it's important to first disconnect the hard start kit and test, because that can be ruled out immediately, if the unit starts. If not, you'd proceed on exactly as you did in this video.

Great video keep them coming 👍🏻

It helps to take a picture of whatever you are taking apart so that you can remember how it goes back together.

@zx8401ztv

Жыл бұрын

Yes, Always a good idea with anything you take apart :-).

I found that on a good induction motor the cap goes south before the windings most times even more recently. Some perfectly good appliances dumped because its quicker and more profitable to fit a new motor with those bolt on caps, than do the job properly. Of corse that was back in the day we all used to fix things. 👍 Sail Safe mate. Ant & Cid

Good video. Thanks you for sharing wish you a lot of health and always happy 🤝🤝🤝🤝🤝💯💯

Well diagnosed 😀 When you said it was humming i mentally jumped back to a bench grinder i fixed years ago. It would not start unless you spun the shaft then powered it up. it could be started backwards. The capacitor was easy to diagnose, it had exploded in the base ha ha :-D I' m now a master capacitor diagnostic tech lol. I'm surprised that they havn't done way with capacitor starting, some kind of mosfets and a timing circuit maybe. Capacitors are cheaper, There I've answered my own question lol.

Hi Dave and great video showing the steps to check a compressor that doesn't start. Personally, I wouldn't install the hard-start kit. As you mentioned, the scroll compressor because of its inherent design doesn't have a load on it when starting. Some folks will say that it has a quicker start up period which will shorten the time that the compressor has high starting amps. This is true, but at the same time this higher starting torque will jolt everything inside the compressor such as windings that may rub the insulation which could shorten the life of the compressor. On compressors that have reciprocating compressors which you won't find in a residential unit, hard-start kits were used to overcome the pressures when starting. And techs would use them on residential compressors to extend the life of a compressor which is near its life possibly because of bad bearings or even wouldn't start. Another disadvantage is let's say that the run capacitor is at low capacitance as in your case or open. The compressor will start because of the hard-start capacitor yet the run capacitor is bad and you wouldn't know it. This will increase the current in the run winding which will shorten the life of the compressor not to mention that the compressor is not running at its highest efficiency because of poor power factor. In other words, your electrical bill will be higher. Have a great day Dave and don't work too hard!

@spelunkerd

Жыл бұрын

Thanks Terry! It's always good to get advice from a seasoned pro. Dave

@spelunkerd

Жыл бұрын

It's been over a month now and the system is working fine, so as you suggest I'll leave it simply with the replaced run cap and continue following. With only a single capacitor doing two tasks, run and start, the cap needs to be sized large enough to do the start task without being too oversized for power factor correction. It raises the interesting question as to whether people who add a start cap should consider reducing the size of the now dedicated run cap, since the run cap doesn't need to be large at all. The higher impedance of a smaller, dedicated run cap will reduce current flow through the more delicate start windings after the motor gets up to speed. I used to think this should be easy to calculate, but the way motor inductance changes with rpm, the best practical way to size these is in the lab. Thanks again for your kind help, Terry.

@stuzman52

Жыл бұрын

@@spelunkerd Hi Dave and glad to hear that your system is running fine. We've been KZread associates for quite a few years now, and I've been happy to converse with you over these years. And as always, I'm happy to help! Have a great day Dave!

Great job - I installed a 521 kit on my 20 yr old Copeland 4 ton compressor just 3 months ago. Interesting that I installed the model for 1-3 ton units. Why? Well I looked into the OEM spec after purchasing the 3-5 ton 521 kit and my OEM start kit had the start capacitor that the 1-3 ton 521 kit had so I switched it out. Have not had any issues. Start up amps went from like 109 down to 75 or somewhere like that. Mine is a scroll compressor so I am hoping it works out ok. I am a little weary of the case where the dual cap might be going bad and not really knowing it or other potential issues that can happen with these kits. All is well so far. My unit is probably on it’s last few years anyway. Great vid thanks for posting! Got the same Fluke - love it.

@spelunkerd

Жыл бұрын

Terry made a good point, about how you might not notice a bad run cap if you have a start cap in place, but I don't know how big a deal that is. Recall that when a compressor has both, the run cap has considerably lower capacitance than the start cap. You don't need a lot of capacitance after the motor is up to speed; it is there for power factor correction. When a capacitor is sized to perform both tasks, as in this PSC motor, it is sized for starting but ends up being oversized for the run cycle. So, if capacitance of your new run winding is a little lower than the original single-capacitor design while running, that may be a good thing.

I don't have that type of compressor, but my condenser came from the factory with a hard start kit. Also, they must not be making capacitors like they did in the past, since bad capacitors seem to be the number one failure for AC condensers now. I don't think it would hurt to install a hard start kit.

I would hold off on the hard start kit if you can. It’s sort of a bandaid to buy more time on a failing unit, but it’s harder on the windings of an otherwise healthy motor. I’d focus on things like making sure the right amount of oil is in the compressor along with its charge, making sure the delay between restart cycles isn’t too close together (some thermostats are programmable for that), and that the right voltage / amp capacity is making it to the compressor to begin with good contactors and connections.

@spelunkerd

Жыл бұрын

When I read the comments thread on any video, I scan for remarks like this, remarks that elevate the discussion to another level. You make an excellent point, check for voltage drop, current draw, cycling frequency, and do an overview of the system for other causes of excessive load, (including silly things like dirty air filters, etc). Thanks for making this discussion thread worth reading!

This literally just happened in my AC unit three weeks ago

It wouldn't hurt to throw the start cap in since it was specifically engineered to have it as an option, but it's worked all this time without one. If you get lights flickering in the house on startup, then I'd probably just throw it in. Otherwise, I'd leave it off. No sense in adding a component that isn't really necessary.

After almost 18 months since this repair was done, with no problems in the interim, this compressor suffered a catastrophic internal electrical failure characterized by a short to ground and shorted start windings. I did a video of how that second diagnosis was made, in this video kzread.info/dash/bejne/m5x4xZSYhNmboto.html The new capacitor shown here is still fine, but it does raise the interesting question regarding whether the failed cap last year caused excessive current draw during startup last summer, shortening the life of the compressor by overheating insulation then. On the other hand, if this was indeed secondary to the failed cap I would have expected those windings to have shorted then rather than more than a year later. These compressors typically last less than a couple of decades so at 19 years of age it didn't owe me anything. In a newer unit one might try to replace only the compressor, but in the past we've had two freon leaks a few years ago and I'm more interested in a completely new unit.

Thank you so much for this video. I now 2/20/24, have a Rheem heat pump unit that DOES NOT start up, at all. The out door unit make an attempt it seems, with a very very fast quick "kinda of a hum, clip" sound, then nothing. And then the indoor unit fans just keep blowing. I am not a mechanic, but handy enuff, to try anything. I will start to change the contactor, then the capacitor. But my concern is if those two items does not work, what else is there to do. I would really appreciate a reply, from you or anyone. Thanks.

@spelunkerd

4 ай бұрын

You may want to check out this video kzread.info/dash/bejne/fmZ2rqqRc8nbkqw.html , where I go through a similar diagnostic procedure in a dehumidifier. I show how to do the diagnostic tests rather than just swapping parts. It's easy, just with a multimeter. As you say the capacitor is number one on your list of possible diagnoses. I should tell you that this week my compressor failed with an internal short to ground, and I did another video of that diagnosis. You're a lot better off doing the diagnostic tests to verify diagnosis first before swapping parts at random. The capacitor is number one on your list of quick fix possibilities, though some also have a potential relay, a current relay, or a PTC resistor. To tell if you have one of those possibilities, search your pump for the wiring diagram, and look for flashing lights on the board that might help you decide what is happening. Good luck!

4 ай бұрын

Thanks, I will. But you know, what , I today changed the contactor and the capacitor, and the outdoor unit STILL DID NOT START UP. And it did the same quick click, like it was about to start, then nothing. I do not know what to do now. But, I will still be trying something like changing he PC defrost board next. Which me luck. But thanks again. @@spelunkerd

@spelunkerd

4 ай бұрын

Don't change the defrost board. Check the circuit drawing to see if it has a switch for a dedicated start capacitor. There are three types. Potential relay, current relay, and PTC thermistor. If one of those is installed and bad in the system, it will give a similar no start pattern. Another thing that can do that is shorted windings, and of course a locked rotor from mechanical failure will do it. You can prove shorted windings with a multimeter. Make sure you know which motor is failing to start.

4 ай бұрын

Mister. Thank you so much for this info. It is not the compressor, I push the contactor in manually, and it starts and runs ok. Thank God, cause I cant afford a compressor job now, i am on fixed income living in Poinciana. The relay assist start, set up is an option, but i am not that verse to even attempt that. I hope i can find the remedy before it get into the summer. Wish me luck. I hope i will find the solution. Thnx a lot again. @@spelunkerd

Compressor kicks fine for AC but will not for heat. The emergency heat works even the blower but the fan outside and Compressor will not kick on during heat. Everything works fine for AC

@spelunkerd

8 ай бұрын

Heat pumps require a specific style of controller in the home to direct AC and heat. I'd be checking the connections there, making sure a wire hadn't come loose, batteries are fresh and the pump is in the heating mode. Our controller can be easily be accidentally bumped into the wrong mode (cooling or heating) by somebody who is simply looking at the temp or trying to adjust the set point. Finding that before the tech is called in to fix it saves embarrassment, ha ha.

@dannyallen9804

8 ай бұрын

@spelunkerd yeah it's really simple thermostat. I'm thinking it's not getting 24v at the board for heat. Most likely weedeater got the wire or possibly the thermostat is bad.

@spelunkerd

8 ай бұрын

@@dannyallen9804 Be sure any new thermostat you get is specifically designed for heat pumps. Normal thermostats off the shelf will not work for most heat pumps that do both AC and heat, and they have no backup mode for emergency heat if the pump system fails.

@dannyallen9804

8 ай бұрын

@spelunkerd yeah my HVAC guy comes tomorrow I will let everyone know

@dannyallen9804

8 ай бұрын

@spelunkerd just a update faulty thermostat not calling for heat. Changed it out My tech ran some test everything working smoothly now. With new thermostat the cool down period and stage changes takes longer than old one but all and all simple fix. Thanks for the help.