# Ac runs for a few seconds, then shuts off



## jbjones

My ac unit turns on for a few seconds, then shuts off. I'm not sure if the actual outside unit kicks on, but I can hear the blower turn on inside. Shuts right back off. I had a repair man come out a month or 2 ago and he replaced the blower motor and capacitor. He also charged the freon saying it was low. The house is staying cool and the ac doesn't seem to be running excessively. The short cycles seem to only happen in the early morning. What could be going on? Thanks


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## jbjones

I meant to say the condenser fan motor was replaced.


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## HVAC1000

jjones1020 said:


> I meant to say the condenser fan motor was replaced.


It could be a pressure switch in the outdoor unit. Your refrigerant charge COULD still be low (or possibly leaking). There are other possibilities too may need more info


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## jbjones

Is something I need checked right away? I already paid a guy quite a bit to do what he did. I don't want to keep sinking money into it if gonna end up needing replaced. Maybe I can do some troubleshooting myself.


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## biggles

if it is cool in the morning might be short of Freon again did he do a leak check at all soap bubbles on lines into the condenser and at the air handler?hi pressure trip would happen in the hottest of the day...is the condenser fan cycling along with the compressor...off the same contactor?if the condenser is short cycling one morning take a garbage can top and put it on top of the condenser/with a brick if the condenser stays on longer with this ...the unit is short of Freon.:wink: reason it does this restricted air will raise the pressures on both sides of the system...don't worry it won't explode...grab that raw thin copper line just out of the condenser...should be warm to hot with this stunt...if not again your short on freon


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## PoleCat

You can also jump out the low pressure cut off switch to verify that is what is shutting you down. You need gauges to determine whether it is a low charge, line obstuction, or faulty LP switch.


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## jbjones

Ok... I tried what biggles said and covered the condenser with a piece of plywood instead of trash can lid. First 2 times, it still shut right off. 3rd time, it stayed running. Not sure if it would have continued even without the wood. Sometimes it does run full cycle. The line that is insulated felt cold, the line not insulated got hot. Once I pulled the wood off, the raw line cooled to ambient temp right away. Covered it back and it got hot again within a minute or 2. If it is low on freon again, should the repairman take some responsibility for it. The unit has never had an issue or been charged in the 6 years I lived here. The day he was here, he mentioned if it leaked out, I might be looking at a new unit. Any thoughts or suggestions?


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## PoleCat

I would at least look for the leak first. It may be in plain sight. Oily residue on the surface of the plumbing is a dead give away. The origin of the leak could be anything from deliberate sabotage to natural causes so don't fret about that.


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## beenthere

jjones1020 said:


> Ok... I tried what biggles said and covered the condenser with a piece of plywood instead of trash can lid. First 2 times, it still shut right off. 3rd time, it stayed running. Not sure if it would have continued even without the wood. Sometimes it does run full cycle. The line that is insulated felt cold, the line not insulated got hot. Once I pulled the wood off, the raw line cooled to ambient temp right away. Covered it back and it got hot again within a minute or 2. If it is low on freon again, should the repairman take some responsibility for it. The unit has never had an issue or been charged in the 6 years I lived here. The day he was here, he mentioned if it leaked out, I might be looking at a new unit. Any thoughts or suggestions?



If you didn't authorize and he didn't charge you to find and fix the leak. Then he isn't responsible for the leak still existing.


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## jbjones

Is it safe to assume it is low on freon then


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## SeniorSitizen

jjones1020 said:


> Is it safe to assume it is low on freon then


It's safe to assume anything and it's done every day, but unless the assumption is followed by a valid test those assumptions can become mighty expensive in some instances.


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## jbjones

I called him back out. Lets see how much he nails me for this time


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## biggles

putting the wood over the condenser and the raw copper getting hot tells me the charge is still there and runs in the hot sun baked days but cycles in the cool mornings in the shade.... slight Freon leak might be there but he needs to check the typical fittings...and your not in need of a new unit....installing both ends new doesn't solve the leak...tell him that when he tries to BS you on the repair...if techs put gugaes on the unit every sping and disconnect them that is your Freon being blown off and the charge is being taken out on a pressure check running over the years...


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## jbjones

So, your saying its not low freon. What are some other possibilities? He's coming out tomorrow now, since its raining. The pipe doesn't get hot without the wood on top.


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## biggles

it could be slightly short in the cooler part of the day cycling off...that heat on the raw copper out of the condenser(liquid line) tells me the charge is there...when you do the blocking trick...:wink: tell this guy you want to see temperature splits....18F on the air handler and 10F on the condenser after his work note the amperage on the compressor and the outdoor temp at the time on his invoice and sign it off unit is working as designed....he will step back and say who have you been talking to.i am taking for granted the filter,coil and supply fan squirrel ROUNDS are mint clean?:thumbsup: he will do a leak check with the exsisting Freon pressure which is slightly OK but not on a major leak as you don't have.for him to recover the Freon in the system and pull a micron test is big bucks in time to you...work him on the other guys showing up and not doing anything...but get those splits:yes:


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## beenthere

> he will step back and say who have you been talking to


I would. And then I tell the customer that who ever it is. Is giving them really bad advise.

Some systems will do more then 18, others won't do close to it. 10 degrees across the condenser may be too little. Having a tech try to meet specs fro someone on the internet isn't a good idea. Too much taken for granted(assumed).


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## countingcoup

Sounds like a little low on charge still. FYI, if your ac quits running after years of use because its low on charge, you got a leak. Freon doesn't go bad(not in our lifetime anyway).


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