I'm so ignorant about HVAC systems! I'm hoping some folks can help me with not getting rooked by some HVAC service guys.

I had my best friend (now deceased) install a brand new HVAC system in my house in the summer of 2002. I've never had it serviced, and tonight I discovered it won't put out cold air anymore.

Who should I call?
What should I look out for?
Could it be as simple as just needing to be recharged with Freon?

Any advice will be extremely appreciated.

This message has been edited. Last edited by: synthplayer,

My AC guy who did a checkup on my system said the first thing to test when my ac stops producing cold air are the caps. But be careful as they are big and dangerous.

Mine went out a few weeks ago. Turned out I needed to replace the batteries in the thermostat. Something simple I didn’t check after running back and forth trying to reset everything.

I suspect since you have not had it serviced for ... 16 years you are screwed.... even with servicing the unit is way past its expected life....

but here is one suggestion which has worked more than once.... go outside to the compressor unit... take the cover off and look for the metal box with the most wires running into it... take a special tool (hammer) and wack that box.

Oh and there is no way you are going to get freon in that thing.... I suspect where you live you will be hard pressed to get any type of gas put in it if it is leaking.

then again, batteries in the thermostat can do that too but usually the thermostat will say low battery but often when you replace them there is a resect button inside the cover that you need to make sure is pushed.

If you're lucky it will just be a bad capacitor. As I understand it, they overheat and swell up and no longer make contact internally. They aren't terribly expensive. The service call probably will cost more than the part.

quote:

Originally posted by synthplayer:
I'm so ignorant about HVAC systems! I'm hoping some folks can help me with not getting rooked by some HVAC service guys.

I had my best friend (now deceased) install a brand new HVAC system in my house in the summer of 2002. I've never had it serviced, and tonight I discovered it won't put out cold air anymore.

Who should I call?
What should I look out for?
Could it be as simple as just needing to be recharged with Freon?

Any advice will be extremely appreciated.

Give us a little more information and we may be able to help you.

When your thermostat calls for cold air what happens?

Does the fan on the HVAC unit kick on? (whirring noise inside the house)

Does the AC compressor kick on? (clunk followed by a grinding noise)

Does the AC condensor fan kick on? (Whirring sound outside the house)

If all of the above happen and its just not cool air, then yes you may need a recharge. If it worked last season just fine, and now doesn't work it's likely not a leak, but a component.

If no whirring inside then your HVAC fan isn't turing. This could be a few things. No power, or fan motor went.

If no thunk and grinding noise then your compressor isn't working. This could just be a fuse, or a capacitor, or the compressor itself.

If no whirring outside then your condensor fan is out. Could be a fuse, could be something chewed the wiring, could be the motor is bad.

Also have you checked the coils to see if they're clean? We've had a heck of a cottonwood bloom this year and ours was caked with the crap. I hosed it out and it made a big difference.

As others have said, if you know nothing be careful poking around as the capacitor even if bad can pack a mighty jolt, not to mention there's line voltage in there too.

There are lots of good videos out there for repairs these days. Search for your symptoms from the above descriptions, or search your make and model.

quote:

If no thunk and grinding noise then your compressor isn't working. This could just be a fuse, or a capacitor, or the compressor itself.

Or the starter relay. I've seen several that had a bug or small lizard keep the contacts from closing.

quote:

Originally posted by arfmel:
If you're lucky it will just be a bad capacitor. As I understand it, they overheat and swell up and no longer make contact internally. They aren't terribly expensive. The service call probably will cost more than the part.

That's what was wrong with mine last year - it was pretty easy to spot and fix.

If you turn off power to the AC unit (you should have a switch outside next to the unit), remove the cover and look for a large capacitor - is it bulged or leaking fluid? If so, that's likely the issue. Very easy to replace and not expensive. Again - make sure you cut the power before you remove the cover.

Can't help on the diagnosis/resurrection.

I will give a recommendation for after you get it up and running (or replaced) though:

Like every mechanical system on the planet (or the galaxy) these beasties need preventative maintenance. Have a pro come at least once a year and take care of the system. Or read up on the system you have, and learn to do what your system needs on your own.

Mine quit working this year and I figured out the coils had just iced up. I shut it off for about 12 hours and turned it back on and away we go.

I did have a bad capacitor once also. Part cost about 16$, they are usually marked on them so easy to replace. Make sure cap is grounded first before you try to remove it, they "store" a charge.

As a tenant in Florida I have learned to check 2 thing before calling.
#1 replace thermostate batteries with Enegizer Lithium batteries once a year.
#2 under the AC handler in the home, see if there is a drip pan. If so and it fills with water it will trip a float sensor that shuts it off. If this has happened, go outside with a shop vac and such the scum out of the drain line.

After that, I have no idea.........

quote:

Originally posted by ShouldBFishin:

quote:

Originally posted by arfmel:
If you're lucky it will just be a bad capacitor. As I understand it, they overheat and swell up and no longer make contact internally. They aren't terribly expensive. The service call probably will cost more than the part.

That's what was wrong with mine last year - it was pretty easy to spot and fix.

If you turn off power to the AC unit (you should have a switch outside next to the unit), remove the cover and look for a large capacitor - is it bulged or leaking fluid? If so, that's likely the issue. Very easy to replace and not expensive. Again - make sure you cut the power before you remove the cover.

I am not a EE for sure, I learned that caps will retain a charge and I have heard stories of electricians who cut power and forget to discharge the cap and get sent across the room when they upset the cap.

All that mentioned as I am wondering from out pros here, what the recommendation is to properly discharge the cap?


HK Ag

 
I was faced with this a couple of years ago, and it turned out that it had sprung a leak in the coolant lines. The telltale on that is oil all over the pad beneath the compressor. If you take the top cover it is even more evident. The issue then is fixing the leak, if they can pinpoint it. And then the whole system needs to be recharged. 16 year old coolant is no longer used and is very expensive to purchase, which means you are probably looking at $700+ just for the coolant, plus the labor to repair the leak. This puts you into the realm of weighing that against just replacing the system. The new one will come already charged with the currently used coolant. At 16 years, it may be the wiser, if more expensive, option. I hope it's not a leak, but you are still at or near the expected life of that system.
 

quote:

Originally posted by HK Ag:

quote:

Originally posted by ShouldBFishin:

quote:

Originally posted by arfmel:
If you're lucky it will just be a bad capacitor. As I understand it, they overheat and swell up and no longer make contact internally. They aren't terribly expensive. The service call probably will cost more than the part.

That's what was wrong with mine last year - it was pretty easy to spot and fix.

If you turn off power to the AC unit (you should have a switch outside next to the unit), remove the cover and look for a large capacitor - is it bulged or leaking fluid? If so, that's likely the issue. Very easy to replace and not expensive. Again - make sure you cut the power before you remove the cover.

I am not a EE for sure, I learned that caps will retain a charge and I have heard stories of electricians who cut power and forget to discharge the cap and get sent across the room when they upset the cap.

All that mentioned as I am wondering from out pros here, what the recommendation is to properly discharge the cap?


HK Ag

Yes, I forgot to mention that ...

I'm not an HVAC guy, but I did short out the terminals with a screw driver multiple times - similar to what this guy did:




Link to original video: https://www.youtube.com/watch?v=ZTQi5rTJIw8

One of ours went out on Thursday, was just lowing ambient air.
Thought it was the capacitor, turned out to be a bad fan motor on the outside unit.

We have semi-smart thermostats (able to adjust via phone), so I went outside & turned it on, compressor kicked on but no fan.

Luckily was still under warranty, so just had to pay for labor.

I usually check the outside box with the fan on top.
Last week, the upstairs until was not cooling and the outside box top fan was not spinning.

Called the AC people and they came out and changed the capacitor and all is well.
200 bucks.

quote:

Originally posted by synthplayer:

Who should I call?
What should I look out for?
Could it be as simple as just needing to be recharged with Freon?

Ask friends, neighbors, co-workers, church members, relatives and other aquintences who they use and see if they are happy with the service they receive.

Shady incompetent companies, if things don't make sense or things get expensive, get a second opinion.

Simple repair would be a worn out contactor, capacitor or the stat batteries.

* There's some very interesting replies...
For all the 'service it yearly comments', do you have your refrigerator serviced yearly too?

quote:

Originally posted by Blume9mm:
I suspect since you have not had it serviced for ... 16 years you are screwed.... even with servicing the unit is way past its expected life....

but here is one suggestion which has worked more than once.... go outside to the compressor unit... take the cover off and look for the metal box with the most wires running into it... take a special tool (hammer) and wack that box.

Oh and there is no way you are going to get freon in that thing.... I suspect where you live you will be hard pressed to get any type of gas put in it if it is leaking.

then again, batteries in the thermostat can do that too but usually the thermostat will say low battery but often when you replace them there is a resect button inside the cover that you need to make sure is pushed.

16 years with no service tells me his friend did a proper install and the problem is likely something simple.

I wouldn't want a system that requires yearly service to operate correctly.
It amazes me what people think is normal, when it couldn't be further from the truth.

*If someone hears something wrong several times, that doesn't make it normal or correct. It just means the person is repeating inaccurate information.

Last week, I came home to a hot house. The fan was running, though. I was 99% sure of the problem, because it happens every couple of years-and to my water well.

Anyway, ants got between the contacts in the magnetic switch, as I suspected. I shut the A/C down, removed the switch and scraped the points. I powered it back up, and it's working fine.

That said, I do keep a capacitor around, as it's a fair distance to a store, shit like this happens at the worst times (night/weekends/record heat), and you get an appointment for late in the week.

I just want to say thank you to all your responses. I purchased a new capacitor ($38.00) and the house is cool again.

Seriously, thanks to the Sigforum, my wife and I are going to survive the heat! I hope I can be of help to you sometime in the future!