How would I troubleshoot an AC unit that isn't working well.
I'm in a rental right now with a useless landlord, so I'm trying to fix the problem myself (or at least find the cause). My home's central air AC unit is working, but doesn't seem to be working well. There is cool air coming from the vents, but its less than I would expect, and when its 80f/27c outside, its rarely more than a single degree cooler. I'm looking for ideas to track down the problem. In particular, between the landlord's neglect and the last tenant's seemingly willful destruction I expect it'll be something maintenance related.
So far I have checked:
The unit size relative to the property (its about 2.5 tons for a 2,500 ft² property) which the internet seemed to say was fine. That said, its a bungalow with no attic and high-cielings, so Im not sure if that could have enough effect to account for this.
Intakes and outlets inside the out aren't blocked by furnature (although what I can see looking into them looks pretty dirty)
I tried removing the furnace filter (which, from my understanding, is also used by the AC inside the house) temporarily, although didn't notice a significant difference.
I checked the cooling fins on the unit outside the house for obstructions, but there was little more than a bit of webs
I'm not an expert on these things at all, but is there anything else I can check or try?
Edit: unfortunately there is some condensation and frost on the coil box, so sounds like its a leak. Guess I'm looking at a fight with my landlord.
Stick a thermometer in the vent. Should be around 50-60°F coming out. You’re potentially low on refrigerant. Any frost on the coil box (usually above the furnace)?
Unfortunately this is 100% not user fixable. Typically requires specialized tools to diagnose and then fix. You also can’t buy refrigerant without a license.
134a is for automotive ac units. Unless something has changed recently, household hvac systems use a different type. It used to be R22 for both, but that was a long time ago. Turned out freon (R22) was bad for the environment.
Not legal and definitely not easy to get local without a license. There’s always someone will to sell on the black market. Also, shit is dangerous if you don’t know what you’re doing. I was trying to give the OP sound advice, you know, what they’re asking for.
Another possibility is the starting capacitor for the compressor motor is bad.
If the capacitor is bad then the compressor motor won't actually start, but the fan will still turn on. This will make it seem like the AC unit is running, but there won't actually be any cooling going on. The fans will still blow air, and it'll feel slightly cooler because it's moving air, but it won't actually be cooler.
Replacing capacitors is pretty easy and not too expensive. However, it can be extremely dangerous so I recommend you leave it to the professionals unless you have some experience working with electricity.
Is the coil outside unusually hot or is the fan outside not running well? It should be moving a lot of air, not like a jet but not like a warm fart either. If that's the only problem then you're in luck.
You said there's cool air from the vents but less than you expect.. less cool or less air? If the blower motor isn't working right that's a fix you can do, you'd just need a new one of the same motor that is in there now. Then it's just a few bolts and screws, maybe a few wire nuts.
Is there icing up anywhere? Particularly at the coil inside the furnace. You may need to turn off the power and open an upper panel to get access to see. If that's happening then the other guy is right and you're low on refrigerant. A combustible gas tester is not super pricy but even if you find the leak you won't be able to fix it yourself.
If it suddenly got really shitty, then it's a big leak and no way around it.
If it's slowly gotten shittier and shittier, so slow you're just now really worrying about it. Then it's likely a tiny pinhole leak. The environmently right thing to do is still to get the leak repaired, depending on your state laws you may not have a choice.
But for a pinhole you can charge it back up and could be good for years, could be good a week.
Now you're a renter, so if you're in a good state you maybe able to report the suspected leak, and then they have to get it checked?
It's one of those things where any one person has a negligible effect, but if everyone goes one way or the other it's a huge effect, so some states say you can't charge without doing a leak check and then they have to fix it before charging.
Check your breaker for the ac. If it's off the central blower will turn on but the ac unit (the part outside of the house won't turn on). Go outside and look if the fan out there is spinning.