OT: residential hvac issues, blows hot air, capacitor type, diy or die and then die

[hummus_aquinas]

Hi there! This query is pretty off topic but I figured The Paceline was bound to have someone knowledgeable enough to help me out with an HVAC question. I even applied to join an HVAC group on facebook to ask but they haven’t approved yet. Any insight welcome; please let me know if you need more details or info as this is my first foray into troubleshooting an air conditioning unit.

SYMPTOM: vents indoors blow hot air
TROUBLESHOOTING:
- Batteries replaced at thermostat
- Buss type fuse on side of ac unit in good condition
- Vent fan turning normally
- Condenser fan stopped, not turning, humming
- Condenser fan “helped along” with long-ass chopstick, started to turn normally, hot air felt to move out/upwards
- Vents indoors blowing cold air (technically cold although doesn’t feel as cold as other air conditioned environments I’ve been in, condenser might need recharge, may or may not DIY this)
DIAGNOSIS: capacitor needs to be replaced
ISSUE: capacitor replacement
CAPACITOR SPECIFICATIONS:
- Big one (?) – 40uf, 370V AC, 60HZ
- Small one (?) – [illegible] uf, 370V AC, 60HZ

QUESTONS: What type of capacitor do I need to buy? Do I need to buy two different ones? I’m not seeing these types of capacitors on homedepot or not even amazon. I’m only seeing round type, dual function (?) capacitors, not sure if I should use a universal type or replace exactly what I see. I’ve included some photos of the panel removed from the unit revealing the electronics and the contacts of the small and big capacitors. Am I even showing the capacitors I need to replace? I see another one to the left side, a ballast (?), etc.

I really appreciate any help or insight you can send my way! I’m enjoying the troubleshooting process just not the ladder climbing and back and forth into the house. Thanks!

https://live.staticflickr.com/65535/48044063016_41fe82fd3e_b.jpg

https://live.staticflickr.com/65535/48044062576_b2453da030_b.jpg

https://live.staticflickr.com/65535/48044062746_e137abd766_b.jpg

[daker13]

I dealt with this in my house last summer. Did you search for the AC type and do some youtube searches for how to do it? There were some pretty good videos on youtube and it looked easy... but I ended up just calling a repairman to do it, and it didn't end up costing all that much. I was surprised by the amount of stuff online to help one DIY, and I could have easily bought the caps from Amazon. But, while I've done some amateur electronics I wasn't comfortable messing around inside the AC and I particularly hate screwing something up and having the professional fix it for me.

[bigbill]

Big one. You can get them at an electrical supply. The compressor fan is capacitor start/inductor run, that's why you can get it to spin a little with a stick. When it starts, the capacitor kick starts it in the right direction until the induction continue running the motor. I kept one on the shelf in my garage, replaced one about every two years in Texas. Make sure you pull the compressor disconnect and ground the old capacitor before you touch any wiring.

Or get a professional. I think I paid about $120 one time. $50 part, $70 labor. For a pro, it's a 15 minute job.

[ScottW]

The universal and/or dual run replacements are okay. They tend to be round instead of oval-shaped cans. As long as it has the same uf and V ratings (equal to or slightly greater than the original) you're fine. Should be able to find a suitable one on Amazon and have it in 1-2 days.
I'm pretty sure the smaller ones are typically rated at 5 uf but I'd have to double-check my spares at home to be certain.

[fmradio516]

If you need a new cap, send me a message. My dad is a distributor and will probably have it.

[OtayBW]

Agree with some of the statements above: make sure you know how to fully discharge the cap before monkeying with it, or else it could....well...;)
Or just get a pro to knock it out...

[ColonelJLloyd]

Make sure you pull the compressor disconnect and ground the old capacitor before you touch any wiring.

I've had a lot of work done on vintage amplifiers and at one point thought since I was handy enough with a soldering iron I would take a class and start doing this stuff on my own. Before that I asked some questions of my repair guy and when he said there was enough juice in one of the big capacitors in a 40w Fender amp to kill me I thought better of it.

Perhaps this is a different situation, but you can't be too careful.

[hummus_aquinas]

Hey! Thanks for everyone's answers and insights, very helpful. A helpful-ass dude on that hvac fb group let me know which one to replace (the small one) and emphasized the importance of matching the uf rating of the capacitor.

For those wondering, the big one is for the compressor (which I bought since the specs were still clear) and the small one is for the fan itself. After a little google investigation, it's a Jard Sevonol brand capacitor, 7.5 uf.
There's an electrical supply vendor right next to work so I skated over on my lunch break to pick up the parts. I'm really glad I didn't have to resort to hondipo or amazon!

How I'm trying to be:
https://p1.liveauctioneers.com/930/18669/6321650_1_x.jpg?auto=webp&format=pjpg&version=1&width=512

[Peter P.]

Don't forget to let us know if replacing the caps solved the problem!

[Peter P.]

Don't forget to let us know if replacing the caps solved the problem!

Tip: If you have a voltmeter that measures capacitance, measure the bad caps and the good caps, and compare. The good caps should be close to the rated capacitance. The bad ones may read open, short, or a value out of range of the original. The experience gained will help immensely next time you run into trouble because you'll know how to verify the caps are good.

Also, label the caps with their value or put tape over the text so it doesn't fade with age.

[hummus_aquinas]

Replacing the capacitors fixed the issue! I ended up replacing both. Although a great idea, I didn't have a multimeter to test for capacitance of the new vs old caps.
I'm thankful to use this as a learning experience as I could have paid someone else do it. I didn't want someone up on the roof without me knowing what the actual fix was and more importantly the process of how it was done. I'm definitely lucky this wasn't a bigger issue than replacing capacitors.
Thanks for everybody's input!

https://live.staticflickr.com/65535/48047075402_327d7c7238_b.jpg

[dddd]

YouTube is pretty amazing when it comes time to do home repairs, car repairs or even bike repairs. I always try to watch more than one video of the same repair as done and explained by two different people in two different regions.
I'm about to do some roof tile work and expect I'll first head to YouTube for "show me how" advice.
Used to be that people doing pro's work on their cars and homes often made a mess of things, and often failed to recognize and adhere to safety procedures while doing it!

I wonder though how much we should be worried about things like job loss and reduced tax revenues as a result of people doing these sort of things themselves!!!

[weisan]

Replacing the capacitors fixed the issue! I ended up replacing both.

well done, good job!

I did the same six months ago. Actually took both out and brought it to a local distributor store to make sure I get an exact match. Even with the original in my hands, one of the store helpers gave me the "wrong" one until I looked at it myself and identified his mistake.

I always say this to people, if someone as mechanically inert as me, can fix cars, repair bikes....change capacitors...anyone can, just need to take the time to do your research, ask a lot of questions, and be willing to give it a try.

[Ken Robb]

how did you discharge the old capacitors?

[hummus_aquinas]

http://i.imgur.com/fjS6270.gif

Per some youtube video I touched an insulated screwdriver at both contacts.