Outdoor unit fan not tuning on sometimes

[dogdad]

Noticed lately that when I come home later in the (hot) day my house is warm. Air is coming out of the ceiling vents, but not cool. When I walk outside the outdoor unit fan is not running. Turning the inside thermostat switch from cool to off , then back to cool starts the outside unit on and the house cools off. I've had to do this about 4 times.. Last year I had to change the outside unit capacitor. Going to change it out again....any other things to look at? It's a Trane ac unit.
Thanks in advance

 

[usa#1]

When you catch the indoor unit running and the outdoor unit isn't on ( don't mess with the thermostat or anything else) go outside and check that the contactor is pulled in. Also confirm that you have voltage on the load side of the contactor. If the fan isn't running you should be able to hear the compressor running unless the thermal limit in the compressor has opened.

 

[stage20]

could be as simple as a start capacitor depending on your unit. check for clean and properly connected female spades as well. sometimes its just the little stuff.

 

[pop pop]

Ants on the contactor.

 

[boo coo tracks]

USA#1 has it , I use insulated screwdriver to push it back in.
Tracks

 

[Forsythe04]

Ran into the same thing this evening when i came home

opened up the unit and there were a pile of ants in between the magnets of the contactor.
When i cleared the ants away my fan still wouldnt kick on. Could they have fried the contactor? When engaged i hear the buzzing

 

[zmaxmotorsports]

When you catch the indoor unit running and the outdoor unit isn't on ( don't mess with the thermostat or anything else) go outside and check that the contactor is pulled in. Also confirm that you have voltage on the load side of the contactor. If the fan isn't running you should be able to hear the compressor running unless the thermal limit in the compressor has opened.

 

[zmaxmotorsports]

Ran into the same thing this evening when i came home

opened up the unit and there were a pile of ants in between the magnets of the contactor.
When i cleared the ants away my fan still wouldnt kick on. Could they have fried the contactor? When engaged i hear the buzzing

Reminds me of a time when I got jolted really good by a piece of conduit in a grocery store.
They had lost a neutral on a circuit feeding a commercial freezer in the meat dept but there were enough dead roach bodies piled up inside of the box the outlet was in that it was actually going through the dead bugs and using the box/conduit as a neutral back to the panel.
That was until I knocked that loose piece of conduit going up the out of its fitting when I grabbed it,That one really hurt!

 

[Forsythe04]

Reminds me of a time when I got jolted really good by a piece of conduit in a grocery store.
They had lost a neutral on a circuit feeding a commercial freezer in the meat dept but there were enough dead roach bodies piled up inside of the box the outlet was in that it was actually going through the dead bugs and using the box/conduit as a neutral back to the panel.
That was until I knocked that loose piece of conduit going up the out of its fitting when I grabbed it,That one really hurt!

ouch! luckily the second time around of cleaning the ants away the unit kicked on. i hate ants!

 

[stage20]

if you verified you have power after the contactor, i would still lean towards a start capacitor for your fan motor if its equipped with one.

 

[LS6 Tommy]

if you verified you have power after the contactor, i would still lean towards a start capacitor for your fan motor if its equipped with one.

Just an FYI, condenser fan motors do not have start caps. They have run caps. Chances are if he doesn't hear the compressor running it's not a fan capacitor issue anyway.

Tommy

 

[dogdad]

Thanks for all the replies...will do some testing..

 

[toyodajeff]

Just an FYI, condenser fan motors do not have start caps. They have run caps. Chances are if he doesn't hear the compressor running it's not a capacitor issue anyway.

Tommy

hey your on maliburacing too arent you? Ive got an 82 el camino so i get lurk on there somtimes

 

[LS6 Tommy]

hey your on maliburacing too arent you? Ive got an 82 el camino so i get lurk on there somtimes

Yessir.

Tommy

 

[dogdad]

When you catch the indoor unit running and the outdoor unit isn't on ( don't mess with the thermostat or anything else) go outside and check that the contactor is pulled in. Also confirm that you have voltage on the load side of the contactor. If the fan isn't running you should be able to hear the compressor running unless the thermal limit in the compressor has opened.

Just came home today and finally found the outside fan again not on but the attic fan was. I went outside and checked the contactor. It was pulled in. Went back inside and turned the thermostat from auto to off back to auto and the outside fan came on. Then turned the thermostat off and checked the outside contactor again and it was pulled out as should be.....sooooooooooo how do I check my white Rogers 1f56-444 thermostat to see if it is the problem? Any wires to play with to check it?? still need to get myself a multimeter...
Thanks again.

 

[Fixin'Stuff]

Without a voltmeter, you're flying blind. Just because the contactor moves doesn't mean that it is transferring power to the load side. Lizards, snakes, bugs and just plain worn out contacts can prevent the power from getting to where it needs to go.

 

[zmaxmotorsports]

Another possibility is a pressure switch wired into the fan side of the condenser wiring,I usually only see that on commercial equipt though.
But ya never know how other people wire things.

 

[justinjoyal]

Compressor maybe shutting down..

Clean filters? Clean condenser?

 

[2Big2Ride]

The earlier advice gives me something to check in the morning.

Murphy's law. Just happened to walk outside and heard a faint electrical hum and a slight hot electrical smell coming from the outside unit (Trane XL14i). Flipped the breakers off and then checked the thermostat, yep, house was warmer than the setting. Pulled the covers of just to look - I know nothing about HVAC equipment. Knocked the wasps nest out of the area below cavity with the electrical components. Contacts seemed moved freely. Flipped everything on and noticed a spark at the contacts when it clicked on, but the fan did not come on and this time there was a louder hum. Flipped all the breakers off for the night.

Last Sunday was devoted to installing a new water heater.

Oh joy!

 

[MFolks]

We had to sleep in a warm house last night,as the outside unit's fan died,so first thing I did this A.M.,was to see if the fan rotated when the compressor started,nope,so called the AC guys. After they replaced the failed fan,everything is good.

 

[2Big2Ride]

Fixed!

240VAC across the contactor and could push start the fan. Found a place open today, that had the rated cap, that would sell to a home owner. Replaced the dual capacitor. Starts now and blows out approx. 18F degrees cooler air than temp inside the house, 91F outside.

 

[Git]

The first thing you should do and probably is the easiest - is just look at the capacitor. Usually involves removing a couple of screws to remove an access cover. If the top is bulged up = bad

Here is mine from last year - it was 12 years old when it blew. Easily replaced by one from Amazon

 

[dogdad]

Fixed!

240VAC across the contactor and could push start the fan. Found a place open today, that had the rated cap, that would sell to a home owner. Replaced the dual capacitor. Starts now and blows out approx. 18F degrees cooler air than temp inside the house, 91F outside.

I've bought extra capacitors and a contactor just in case it's needed down the road....good to have on weekends and late at night if needed....

 

[dogdad]

The first thing you should do and probably is the easiest - is just look at the capacitor. Usually involves removing a couple of screws to remove an access cover. If the top is bulged up = bad

Here is mine from last year - it was 12 years old when it blew. Easily replaced by one from Amazon

I'm still waiting on it to act up again now that my fluke has arrived so I can do testing. I don't think it's the capacitor as its not expanded as bad ones do...and its relatively new....but you never know.

 

[2Big2Ride]

I've bought extra capacitors and a contactor just in case it's needed down the road....good to have on weekends and late at night if needed....

Funny - I bought two caps so now I have a spare. Thought about getting a contactor to have just in case, but stuck with just the capacitors.

 

[manwithtools]

Just encountered a failed cap three days ago. Fan was running, I could here the compressor try to start for a few seconds, but no go. $12.05 later we were back up and running, probably saved $200.

 

[Doc]

My AC was just doing this last week. It was the small fan capacitor. The large cap for the compressor was fine. The fan cap was new last year. not swollen/bulging. Now it was failing but not bad. It was pulling too many amps causing the compressor and fan to overheat causing it to shutdown by the thermal protection built into the compressor and fan.

Good luck.

 

[MFolks]

Capacitors can survive for many years,or just up and quit the next day. In the 1970's,I worked in Ca,at a company that made large electrical power conditioning equipment. Some unite were 3 phase,but most were single phase,both used capacitors of several types;oil filled,or with the foil wrapped layers inside the housing.

During testing,caps could fail,squirting the oil,or shooting the foil layers out like a fourth of July fireworks. It made for a somewhat messy clean up,as the oil was slick,and some caps contained cancer causing PCB's (PolyChlorinatedByphenols).

 

[dogdad]

Really like this sight as it so informative with all the knowledge of the members and willing to help the rest of us out..greatly appreciated!!! As stated previously by members on this post, one needs to check the outgoing voltage of the contactor. So after looking at some YouTube videos...some say check the voltage, another says check the continuity (?). One requires live juice , the other doesn't. Is the continuity test conclusive in showing whether the contactor needs replacing?

 

[Doc]

mine was tested disconnected from the ac unit.

 

[dogdad]

mine was tested disconnected from the ac unit.

Wasn't it your capacitor you changed? I'm asking about the contactor...