Air Conditioner help need. Need answers fast

SD,
it 90 here in south west Ohio and my A/C unit decide it was a great time to stop working. I know almost nothing about how it works so could use some help. The fan on the condenser unit outside is running fine but there is no air whatsoever coming out of the vents inside the house. What can I check that could be the culprit?

The unit is a Lennox and is at least 16 years old(was here when I bought the house in 2000).

Thanks for any help you can give,

CnCdad

Check breaker box, first.

If you can get to the blower motor, there might be a reset button somewhere on the housing.

Thanks Burpo, breakers are all good. So the blower is in the outside unit, correct?

Could be a couple of things.

First, what kind of AC unit do you have? Window unit? Central air (with the compressor/condenser unit outside sitting on a concrete slab)? Some other type of unit?

Second, is the thermostat working? How you would test it would depend on what kind of AC you had, but generally, if you set the temperature high (above current temperature), the unit should turn off. If you set the temperature low, the compressor should turn on and air handler should begin blowing air out the vents.

When it turns on, does the compressor come on, or is it just the outside fan? This can be a little tricky to tell, but the compressor is pretty noisy and it can be heard over the fan. There is a capacitor and a set of contacts that starts the compressor, either of these components could be bad.

The quickest and easiest fix is to call an AC professional. If it is just a capacitor or contacts, it will probably cost less than $200 or so. Being a 16 year old unit (or older), it might just be dying.

Ex,
its central air. So I tried setting the temp above what it is and I can hear a click in my attic as something turns off and then back on when I lower the temp. The way its set up is the duct work(and maybe more stuff) is the attic. the house is a tri-level and there are only vents for the top 2 floors. The condenser unit is outside but that is about all I know for sure. Could the blower be in the attic?

And yea, it may just be dying. sadly$$$

Have you checked craigslist if it does die? You’d assume late september would be a good time to buy a used one.

Except there has been a heat wave lately, pushing 90.

Hell, the new ones are cheap this time of year.

http://www.sears.com/kenmore-5-000-btu-window-mounted-mini-compact-air/p-04286050000P?sid=IDx01192011x000001&gclid=CMrl__LRps8CFVc6gQodeSsPKw&gclsrc=aw.ds

Well, if you’re interested, type the make and model into Google and see what comes up … study what does come up and chase down all the components and their respective reset buttons.

Or call an AC guy …

Generally speaking (and in no way always) when the reset button needs pressed, the days are numbered for whatever unit we press the reset button for. Sixteen years in getting a bit long in tooth, if the AC tech buys you some time maybe start saving money up for your replacement.

It sound like the blower is in that attic. Actually called the AHU (air handling unit). If you are not getting any air blowing in the house, your problem is with this unit.

Can’t take long, but it’s probably the capacitor for the fan in the inside unit (air handler). If you know what you’re doing you can inspect it, if there’s oil coming out of the capacitor that’s a telltale sign. Even with power off at breakers and at the unit itself, capacitors can still carry a charge.

Is the fan running inside?

If yes, the “coils” inside could be frozen into a block of ice, not allowing air to flow. Leave it off 24 hours, then see if it works. If that is the problem, check the drain and air filter for the inside unit.

Could look like this inside the inside unit…

Check to see if you have a local Habitat for Humanity “Re-Store.” Many wealthy people buy a new house and immediately replace the standard builder’s appliances/HVAC units with higher grade ones. The builders swap it out for them and donate the “new” standard units to HfH.

It’s a great way to get what you need for very little. And if you truly can’t afford it, talk to the manager, they are generally willing to give you a break on things they think will be just sitting around for a while.

There’s two parts to central AC: The outside compressor and the inside air handler. The outside has a fan, but it’s to cool off the freon. The fan inside your attic is what moves the air around your house and over the cool coils in the air handler. It sounds like the blower in the air handler isn’t coming on.

From the thermostat, turn off the AC and wait until everything goes quiet. Most modern thermostats have a switch or button for Fan On. This turns on just the fan in the air handler to move the air around your house. Turn just the fan on and see what happens. It could be the blower fan or the electronics which aren’t working. Those can be a little tricky to diagnose for a novice, but they should be relatively easy for a tech to replace.

If you instead decide to get a new AC, wait until the winter. Patch up your system so it works for now. If you wait until the off season, you’ll be able to get more competitive rates for a full AC replacement.

Look at your outside unit. Does it have any ice on it? If so then your inside coil is probably iced up. Turn unit off for 24 hours to let ice melt.

When was the last time you changed the air filter? Check the condition of the filter.

Check air handler in the attic. Can you hear the fan turning? Is there a local circuit breaker or fuse on or near the air handler?
Also if you decide on a new AC unit get 3 bid. Make sure the contractor does a load calculation on your house, stay away from contractors that SWAG the load and size of the unit.

I’m going to say that it’s the fan relay in the air handler. The fan has two speeds, one for cooling and one for heating. A typical test would be to turn the heat on and if the fan turns on then it’s for sure the relay.

I’s also suggest looking at the dataplate on the air handler, which will be the big box in the house somewhere, and see if this is a common problem. I had this same issue at a condo I used to own and so many others were paying people to come out, told them all what it was since we had the same HVAC system and same symptoms and no one believed me. Then, one guy listened…

Either way, it’s an easy fix, just buy a new relay online and replace. Ten years ago it was like $30 with shipping and was fairly easy to replace with a flat head screw driver to reconnect the terminal wires.

As others said and it’s my guess, that it’s icing up. You really need to get up there (even poking your head up in the attic) and listen to hear if it’s running. Turn your T-stat UP so it doesn’t call for AC and just tell it to turn the fan on. Then poke your head up there and see if you can hear it spinning. A bad cap will usually result in a sort of grinding/buzzing sound every few seconds until it times out, probably not the case.
It’s also probably not a bad t-stat since the compressor (outdoor) unit is coming on. I can go into detail, but, I’ll rule that out.

I also doubt it’s a blown fuse since it probably (but I won’t promise) be able to call for the compressor to turn on with 120v service to the air handler (furnace).

Assuming you can hear it running, it’s very likely iced up. You’ll want to find the root cause, scratch that, you’ll hope it’s due to a dirty filter*, so check the filter, if it’s dirty, change it. Someone up thread mentioned just leaving it off for 24 hours. That will let it thaw. A faster way is to let the fan (and the fan only) run for a while. The moving air will clear the ice much faster. Hour(s) instead of a day. Since this isn’t in the basement, you’ll probably want to keep an eye on the drain pan/tube. Both because if it’s iced up, you’ll see it draining and also because if it’s iced up you’ll be seeing a lot of water coming out and if the tube is clogged it’s going to over flow. Overflowing on a concrete basement floor isn’t that big of a deal, overflowing in the attic might be.

If you can get up there, you can check the code on the board by pulling off one or more access panels and looking for a blinking light (and a legend), though, off the top of my head, I’m not sure how much info it’ll give you for AC, it’s mostly designed for furnace switches/faults.

*Couple more things. If there is ice, it’s either a blockage (usually dirty filter or dirty evap coils) or you’re low on refrigerant. The filter is easy. The coils are harder. Low charge requires a pro.

electronbee mention that it could be a fan relay. That’s on the board and could require a new board. You might get away, if you have the option, of switching it to a different speed, but if you have a bad board, they can be pricey to swap out. Sometimes, enough that it’s worth (at least) getting quotes on a new unit. If you’re current one is old.

If it’s a bad cap, they’re very easy to swap, but take pictures before you remove it, especially if it’s a combined start/run cap, so you put all three wires in the same place. If you have the know-how, do that yourself. It’ll take 20 minutes and $30 or repair guy 20 minutes and $150.

As I re-read this thread that I realize is several days old, I see that you mentioned you can hear a click when you move the t-stat up and down. That’s good. It likely means the relay is working. But I’d still want to know if the blower comes on when you set it to fan-only, that’ll go a long way in troubleshooting the problem…short of you opening up the plenum (there’s usually an access hole) and checking for ice.

This is one of those things that difficult to diagnose over the internet. We can help you, but only with the information you give us. OTOH, I could be standing there with the case wide open and say 'look, this wire is totally burned up, there’s your problem. Or, while I’m comfortable just hooking a motor directly up to line voltage to rule it out, many people aren’t.

So, are you still having this problem? If you are:
1)have you checked the filter?
2)any thoughts on the ice situation?
3)Do you have a voltage detector and are you comfortable working with it?
In the end, as long as you have a full charge (difficult for a novice with no meters to tell, I know) and you’re comfortable poking around and replacing parts, you can probably fix this yourself, either something needs to be cleaned or replaced. Just cross your fingers that there isn’t a leak.

FTR, shadetree (and mostly commercial) HVAC is what I do on a regular basis, forgive me if I got any details wrong in the middle of the night trying to walk my way through this without a lot of info.