Help...Air Conditoner experts

steveinaz

Having a problem with our home AC unti. Last year it would occassionally trip the breaker (at the main box), and a simple reset got it going again. When it started happening more often (but still intermittent) we called the AC guys. They tested it extensively, replaced al the huge capacitors on it. Couple days later, the ckt trips again. The guy came back out, and admitted he wasn't really sure what was causing it. He decided to try adding a soft-start unit to the AC to see if that might address the problem.

FFoward to this summer, it's tripping the breaker again--but still intermittently. It does it in the heat of day, and when it's a cool night, so ambient temps aren't the issue. The house/AC unit are 7yrs old this year.

Could I have a bad breaker? Any ideas? I'm thinking I need to call an electrician, not the AC guy?

disneyjoe7

Do you have an amp probe? If so check the amperage on that breaker which is tripping. If not try to replace the breaker, it could be bad also.

Polkie2009

Sounds like your a/c man installed a 521 compressor saver to the unit. I'm taking when you say it tripped the breaker, you're referring just to the 40 amp(or whatever amp rating CB is recommended by the manufacturer of your unit) breaker just for the A/C condesing unit outside? I have seen where a condesing unit caused a MAIN BREAKER to flip before also. Does the unit shut off immediately upon start or after it has been running? Without knowing how old the house is or if the circuit breakers are original, doesn't hurt to go ahead and try installing a new circuit breaker of the exact same amperage in it's place. Seems like over the past 5 or 10 years, my area has had more and more brown outs,power interruptions, surges etc... and it takes it toll on electrical components such as these.

nadams

disneyjoe7 wrote: »

Do you have an amp probe? If so check the amperage on that breaker which is tripping. If not try to replace the breaker, it could be bad also.

Yep... if the A/C seems to be checking out, replace the breaker. They can get weak over time.

steveinaz

It's the breaker at the Main house box (200a service) that is tripping, not the dedicated breaker out by the AC unit. It seems to be tripping at start-up, not in the middle of an AC cycle. The house and AC are 7yrs old this past August. It's very intermittent; for example this summer it's only tripped twice.

Do breakers just pull straight out?

disneyjoe7

steveinaz wrote: »

It's the breaker at the Main house box (200a service) that is tripping

:eek::eek::eek:


Yes this could be bad also, and yes you need to call someone.

steveinaz

Not the "Main" breaker, but the 40amp breaker for the AC unit IN the main box.

RickTfromAZ

Steve,

It is very possible that it is the breaker. Even if it isn't, I would replace it. Every time a breaker trips, it's rating becomes lower and lower. Also check all of the connections at the breaker, as well as the unit itself to make sure that they are tight.

It could also be the compressor contactor. These can occasionally hang up and not make a solid connection between the contact points causing a high current condition.

How long does your unit typically go between start and stop cycles? It may need a time-delay installed to allow the system to equalize before another start cycle. Since it is also happening during cooler ambient temps, this may not be the problem. I'm assuming that you have a split system and not a package unit. Hard start kits are rarely needed on a package unit unless the complressor is nearing end of life.
If you would like, I could drive down there and check it for you. I'm an A/C guy.

amulford

^^^what he said^^^

Do breakers just pull straight out?

You pull the cover, disconnect the black wire, and pull it out. It should click onto some sort of rail and swivel in and click to make contact with the bus. With the breaker off, reconnect the wire and secure it. Simple as pie...

disneyjoe7

Question "Can a Handyman" change a main breaker? Or does the main meter be removed first?

amulford

Nah, you could do it. Just respect you have 220V in there. No poking around with metal thingys...

Polkie2009

Rick is right, I've also seen where ants got into the compressor's contactor and shorted the contactor out. Compressor was fine, lol, but ants and contactor was annihilated

disneyjoe7

Ok never had replace one of those before just checking.

steveinaz

Rick, the house is really well insulated so generally I would guess it's probably at least an hour/ hour and half between cycles on really hot days; probably longer in the cool desert evenings.

During the day we're both at work so turn the ac off. When we're home, I generally set it between 72-74 degrees, depending on how hot it is outside.

I really appreciate the offer, but I don't want to inconvenience you---that's a heck of a drive. Let me try a few things first, see if can resolve it. If these local knuckleheads can't figure it out, I'll definitely pay you well to get this pup running right. It's so intermiitent, that it's really hard to peg down--so I know it's hard for the AC guys to pin-point it too.

steveinaz

Polkie2009 wrote: »

Rick is right, I've also seen where ants got into the compressor's contactor and shorted the contactor out. Compressor was fine, lol, but ants and contactor was annihilated

If the AC runs fine otherwise (once the breaker is reset) could it still be the contactor?

amulford

Yep. if the contacts are going, it could still make a connection.

jimsvm

Anyone ever clean the condensing unit??

RickTfromAZ

One more thing. Check to see if your wiring between the panel breaker and the unit disconnect is copper or aluminum. If it is aluminum, there is a very good possibility the conections will need to have NoOx applied to the wire ends and the connections retightened.

Well, two more things. If you have a "stab" Disconnect at the unit,check to see if any of the knives are discolored from a poor connection or if the fuses are loose. If so, you will need to replace this disconnect.

No, three. Another remote possibility is that something is dragging the control voltage down. This would not allow the compressor contactor to pull in fast enough or not pull in fully. A lot of times the factory control transformers are marginally sized. I've had to end up replacing or adding a second control transformer after a contactor replacement because the replacement contactor coil pulled just enough more current to drop the control voltage.

steveinaz

All copper wiring; local code doesn't allow aluminum wiring anymore (thank God). I'll check the stab disconnect.

Jim--if you're talking about making sure the fins are clear, yes--I keep that clean, and the are around the AC has nothing but gravel; no bushes/plants etc; nothing restricting flow.

jimsvm

In the heat of the day its dropping out. Im calling dirty or condensener fan stopping from too much heat. Short cycling on high pressure contol if equipped with one. Bare bones units don' t have them.

steveinaz

It's also tripped the breaker at night--in cooler outdoor temps.

Thanks guys, really appreciate the advice. I'll check the contactor; stab disconn; re-check to make sure the condenser fins are clear, etc. If that looks to be operating properly, I'll put a new 40A breaker in.

I'll also look at the last work Berg's did on it to see if they may have replaced the contactor. I know he told me that when he was finished, I pretty much had all new "electronics." He checked the fan operation, and said the fan was fine; he also did add a little refrigerant, but he said it didn't need much.

Again, THANKS GUYS!

BlueFox

I had a spa issue that kept tripping the breaker. It appears that when it happened there was arcing in the panel where the breaker connects, and it resulted in pitting at the contact point. Ended up getting the entire panel replaced, which actually was a good thing.

steveinaz

Yep, I've wondered about the integrity of the connections; if maybe some wiring needs to be cinched down. This is a small town, and construction/attention to detail isn't the best I've seen by a long stretch.

jimsvm

The temperature of the breaker in question is hot to touch while ac is on will also indicate if the breaker in toast. A lazer thermometer could also be used. Tuun on stove or range to compare breakers

Polkersince85

Don't overlook the house and unit's grounding wires and rods. Poor grounding can also cause a lot of issues.

rpf65

I would start by rechecking the capacitor. If that thing is weak, the start assist unit isn't going to helpvery much. Heat kills those things. I would also make sure a kick-start brand hard start was installed. That's all I carry on my truck. Some high end Carrier/Bryant and Trane/American Standard condensers only like the factory ones.

Also Trane/American Standard condensers have a little "stick type" crankcase heater. It's located under the compressor casing, and those wires are notorious for insulation break down.

obieone

Steve, OPEN the breaker manually, check voltage to ground on both legs, then across both terminals feeding the condensor. Once you've ensured you have no voltage coming out, take a screwdriver, and check the tightness of the lugs where the wire attaches to the c.b., AND check the tightness of the lugs outside, on both your inlet(coming from the panel), and outlet(going to the condensor). You may just need a new disconnect. They're like <$30 at HD, or Lowes.

steveinaz

Will do, thanks.

westmassguy

Compressor contactor would be my first guess. The contacts can become pitted/scored, and cause higher current draw. A dirty coil can cause this as well, but since it's happening at night, doubtful.

jimsvm

How did you make out with ac?

steveinaz

So far I've only checked the bladed disconnect. It looks fine; no discoloration,etc. This weekend I'll start digging in.

Been busy prepping the master bath for some upgrades.