Air Conditioner / Furnace Troubleshooting (2 Viewers)

[PAToyota]

So, yesterday I went to turn on the A/C (whole house - turned on from thermostat) and just heard a buzzing from the basement. Turned it back off and went down to take a look. Checked the fuse and then pulled the covers off the furnace to take a look at anything. Nothing seemed out of order and no weird smells (magic smoke released) or anything. Went back upstairs, turned it back on, it buzzed for a moment and then stopped before I could get back down to the basement to see what was going on. Went down to the basement again and nothing was happening - no noise, no smells, no nothing... Went back upstairs and turned the fan over to "on" from "automatic" and still got nothing.

I had other things that needed to be done, so I turned things off and left it. Today I had some time (well, not really, but this took precedence over the other things on the list) so I did some online reading to confirm my suspicion that the capacitor for the blower motor was the likely culprit. Looked everything over in the basement again. The capacitor didn't look obviously damaged. Turned off the power at the furnace, went upstairs, turned the a/c on, went back down to the basement, and while watching things flipped the power on... And everything worked as it should...

Stood there watching it for awhile. Nothing out of the ordinary. Finally went upstairs and worked on other things for awhile. After awhile I cycled it off, waited awhile, and cycled it on again - no issues. Did this a couple times - still no issues.

Considering that initially it buzzed, stopped buzzing, and absolutely nothing worked at all, I'm a bit confused. So if it is the capacitor I'm figuring I'm living on borrowed time and should replace it. However, before I go and do that is there anything else that could be the issue? I don't want to replace the capacitor and then find that it is something else. Particularly since I've been here for the long weekend but will be back to work tomorrow and don't want something going on with things while I'm not here. The whole system (furnace and a/c) was installed before I bought the house thirty years ago and hasn't had any issues other than routine maintenance and replacing the fan motor on the a/c condenser unit outside about twenty years ago.

While googling, I see recommendations to budget $150 to $450 to replace the capacitor - which I find ridiculous considering a capacitor is $10~$20.

 

[greenbeast]

Just paid $95 to have capacitor replaced Parts only). Talking out my butt here could it possibly got hot then had opportunity to cool down and function correctly? Like yours the trailers AC unit would only make a buzzing sound, it was sure nice to get it fixed, trailer was 93 degree's by time it was fixed.

 

[Waorani]

Get the specs on the capacitor(s) and get off ebay/amazon. After too many times w/o AC only to need a $15 capacitor replaced, I watched youtube videos, read specs off existing caps and bought spares to keep on hand. Gotten my AC back a couple of times for fraction of having a tech do it.

That said, you really are on borrowed time at 30 yrs. I just replace my whole house system this year and one of my shop units at a cost of $16k - ouch!

 

[PAToyota]

Talking out my butt here could it possibly got hot then had opportunity to cool down and function correctly?

That doesn't seem to be the issue because it was when I first went to turn it on yesterday that it happened. The weather has been decent, so I haven't run it for awhile.

I've got a capacitor coming from Amazon tomorrow - $8.

Yeah, I've been looking into upgrading to a heat pump, just wasn't ready to do it right now. Other than replacing the condenser fan, it's always run without trouble before this. It's been years since I even had them out for refrigerant. I do the maintenance myself and it still blows cold.

 

[Waorani]

Final straw for me was holiday weekend (probably Labor Day now that I think about it) in rental house in Phoenix while on a job. Four days in AZ summer heat w/o AC waiting on repair guy that took all of 10 minute once he finally got there and simply replaced a capacitor.

DIY isn't hard at all if you have the correct capacitor(s). Mark wire colors on new one before pulling off old and keep your fingers off the terminals in case still holding a charge.

 

[PAToyota]

Yep. Should be a pretty simple swap.

The A/C has been running fine all evening. It just started up again and this time it buzzed a bit as it turned on.

Other than the capacitor, the only thing I could think of would be the relay. I wish I could get it to do it when I'm in the basement so that I could see what the noise is coming from.

 

[PIP]

HVAC is such a racket.

Electric motor rewind shops have every size capacitor there is usually for reasonable prices.

If something goes electronically wrong in your air handler there's a control board in there with relays and safety junk. If you google the number on that board you can usually buy the entire board for under $100.

 

[pb4ugo]

Thru the yrs, my capacitor failed a couple of times. The 1st time a hvac guy came and replaced it. The last time I did. A lot of capacitors are found in the unit outside. I found testing procedures and resistance #'s for the one on my unit on the internet to confirm it was the issue.

 

[PAToyota]

So, time for an update.

Replaced the capacitor and then the buzzing lasted long enough for me to get down there and determine that it was the relay...

When I ordered the capacitor, I debated just getting a relay too. Well, now they've both been replaced and everything is functional again.

However, while buttoning things back up and putting the cover panels in place I hear a noise and the humidifier falls off the other side of the ductwork.

Take a look at that and find that the "professional" who put it in - either from his own butchering or the butchering of the previous humidifier installation - basically had the humidifier duct taped in place. The hole for the humidifier was too large, so only one of the screw holes in the humidifier frame lined up with actual sheetmetal in the ductwork. So he put the one screw in there and then duct taped around everything to hold it in place... Without knowing what was really going on, it just looked like the duct tape was to seal the humidifier to the duct.

I do have to say that as I had the humidifier replaced in 2004 it did last nearly two decades like that, so at least he used good duct tape...

So I went out to the shop and cut a piece of sheetmetal so that it would cover the entire hole, cut a hole in that to fit the humidifier, screwed the sheetmetal in place to the duct, and screwed the humidifier to real sheetmetal.

HVAC is such a racket.

Over the years I've seen so much of this kind of stuff that it isn't even a surprise any more. It just makes me

Years ago a "businessman" told me how I was stupid for doing stuff myself - that I could make more money "working" for that time and just pay someone to do the "labor" stuff for me. Between the rates the "professional laborer" charges, the markup on parts, the time it takes to get them to do it, and the fact that I end up spending more time fixing their work afterwards than it would have taken me to do correctly in the first place and I think less and less of that "businessman" with each passing year...

 

[Rugy]

While I was away on vacation, working on my cabin client phoned me that his AC isn't working.
Told him he woiuld have to wait till I'm back in Sept.
It's to hot, told him my AC guy isn't taking on any more work as he is getting ready to retire.
"A friend has a really good ac guy , will ask him to take a look."
Week later he told me that the compressor and the air handling unit in the attic both need to be replaced. Plus we have to open up the roof and the ceiling to get the new gear in place.
Got back to the city, called my # 2 guy to have a look.
He diagnosed the situation , new filter for the unit in the attic and the capacitor needed to be replaced.
Total time on site plus windshield time was a bit over 2.5 hours.
Invoice was $381 CDN.
Owners friends AC guy saw the address ( first Shaugnessy ) and figured he could charge what ever he wanted.
First Shaugnessy is a very prestigious area 8 min from downtown Vancouver. When a property comes up for sale it is typically 10- 30 million.