My A/C circuit breaker tripped two nights ago (after a huge rain shower in the evening), and each time I reset it, it tripped within 3 seconds. I then, shut OFF the Main, reset the A/C circuit breaker, and then turned ON the Main. The A/C has been working fine ever since. What do you think was the problem?

My A/C circuit breaker had tripped once last year, but I reset it and the problem went away; I did not have to turn OFF and ON the Main at that time.

Regards,
K

Problem can be any one of several reasons, such as a defective breaker, or loose connections at the breaker causing heat that is being conducted into the breaker and causing the tripping, or a short in the wiring that is intermittent, or a device in the AC unit that is failing.

Without doing a visual check and checking the wiring and devices,ie: compressor or fan motors, all can be done is speculate.

Even after inspecting, there still may be no conclusive reason found, and the problem may need to be allowed to get worse to be able to find the cause.

I will copy this over at the HVAC forum, see if any of the resident HVAC experts can offer any additional advice.

Problem can be any one of several reasons, such as a defective breaker, or loose connections at the breaker casuing heat that is being conducted into the breaker and causing the tripping, or a short in the wiring that is intermittent, or a device in the AC unit that is failing.

Without doing a visual check and checking the wiring and devices,ie: compressor or fan motors, all can be done is speculate.

Even after inspecting, there still may be no conclusive reason found, and the problem may need to be allowed to get worse to be able to find the cause.

I will copy this over at the HVAC forum, see if any of the resident HVAC experts can offer any additional advice.

Thanks tkrussel! I shall save you the trouble and post it myself.

Q: I do have an annual HVAC contract. Would the HVAC company be able to find the problem during their inspection or does it have to be a service call?

Regards,
K

My A/C circuit breaker tripped two nights ago (after a huge rain shower in the evening), and each time I reset it, it tripped within 3 seconds. I then, shut OFF the Main, reset the A/C circuit breaker, and then turned ON the Main. The A/C has been working fine ever since. What do you think was the problem?

My A/C circuit breaker had tripped once last year, but I reset it and the problem went away; I did not have to turn OFF and ON the Main at that time.

Regards,
K

This,


Q: I do have an annual HVAC contract. Would the HVAC company be able to find the problem during their inspection or does it have to be a service call?

Regards,
K

Will depend on how the contract is written. An annual inspection most likely is just that, one visit per year to clean and inspect the unit.

Any problems found during the inspection may or may not be included. Most likely not be included, and any repairs will be extra.

This problem, unless checked out during the inspection, and if you can bring them in now, most likely will need a service call.

Even if done during the time of inspecting, I believe this would fall under extra work, and be billable over and above the inspection.

Read your contract.

Tkrussel:

I really appreciate your prompt response. Will read the contract this evening when I get home. I have Home Warranty Service, so hopefully they should be able to cover this.

Regards,
K

What do you think was the problem

You might have answered your own question.

My A/C circuit breaker tripped two nights ago (after a huge rain shower in the evening),

It might just be that simple so check over all the wiring in the outdoor disconnect and unit for starters.

BTW on problems such as these you really need to be ON SITE to figure them out.

What do you think was the problem

You might have answered your own question.

My A/C circuit breaker tripped two nights ago (after a huge rain shower in the evening),

It might just be that simple so check over all the wiring in the outdoor disconnect and unit for starters.

BTW on problems such as these you really need to be ON SITE to figure them out.

Thanks for your reply.

What do you think was the problem

You might have answered your own question.

My A/C circuit breaker tripped two nights ago (after a huge rain shower in the evening),

It might just be that simple so check over all the wiring in the outdoor disconnect and unit for starters.

BTW on problems such as these you really need to be ON SITE to figure them out.

Here's an update. The A/C's circuit breaker tripped again last night, and this was without any rain at all. I shut off the Main, reset the A/C circuit breaker, and then turned ON the Main. The A/C circuit breaker tripped again. So, one more time, I shut off the Main, reset the A/C circuit breaker, BUT this time waited for 30 seconds and then turned ON the Main. A/C's working fine since then.

Eager to troubleshoot with my subpar electrical skills, I decided to replace the A/C circuit breaker today because if that was the problem, it would save the $100 trade call fee on my Home Warranty service. The circuit breaker was 20 yrs old. When I removed the old A/C circuit breaker, I noticed that there was a thick grey liquid where the A/C's two wires were connected to the screws... seemed like something had overheated and melted. I checked the wires and screws of all the other circuit breakers and they all seemed fine. So, I wiped the end of A/C's wires, and replaced the A/C circuit breaker. The A/C's working fine... it's been only 1 hr so far since the replacement.

But my question is that now that we know about the thick grey liquid as a result of possible melting, was the A/C circuit breaker the root of the problem? Or does this overheating/melting indicate a serious problem and requires a HVAC specialist to check it out?

Please advise.

Thanks,
K

Here's an update. The A/C's circuit breaker tripped again last night, and this was without any rain at all. I shut off the Main, reset the A/C circuit breaker, and then turned ON the Main. The A/C circuit breaker tripped again. So, one more time, I shut off the Main, reset the A/C circuit breaker, BUT this time waited for 30 seconds and then turned ON the Main. A/C's working fine since then.

Eager to troubleshoot with my subpar electrical skills, I decided to replace the A/C circuit breaker today because if that was the problem, it would save the $100 trade call fee on my Home Warranty service. The circuit breaker was 20 yrs old. When I removed the old A/C circuit breaker, I noticed that there was a thick grey liquid where the A/C's two wires were connected to the screws... seemed like something had overheated and melted. I checked the wires and screws of all the other circuit breakers and they all seemed fine. So, I wiped the end of A/C's wires, and replaced the A/C circuit breaker. The A/C's working fine... it's been only 1 hr so far since the replacement.

But my question is that now that we know about the thick grey liquid as a result of possible melting, was the A/C circuit breaker the root of the problem? Or does this overheating/melting indicate a serious problem and requires a HVAC specialist to check it out?

Please advise.

Thanks,
K

Is the A/C wiring aluminum?

Is the A/C wiring aluminum?

I am almost certain it is aluminum, but how do I confirm it for you?

Regards,
K

That thick liquid as you call it was probably DeOx compound. It is usually used on aluminum wire to prevent corrosion. I will post back a bit later the dinner bell just went off. LOL

If the wires are loose on breaker, or a burn buss(what breaker plugs onto), it can trip breaker.
Inside breaker for Air Handler stays on, but circuit to outside disconnect is what's tripping?
If so and no short, could be compressor or fan,
An Amprobe can show where the high current is going.

This is why a fee is needed, for a professional with all the expertise needed to do this trade.

Good thing your getting advice here.

The generic name of the gray liquid is an anti-oxidant compound, it prevents aluminum from oxidizing from water and moisture in the air. Aluminum oxide is less of a conductor than bare aluminum, and can create a heated connection, and where there is heat, well you get the point.

The gray compound needs to be replaced.

Thanks for all the replies. However, I'm a little confused now.

Did I royally screw up by removing the old A/C circuit breaker, wiping off the deoxy liquid from the wires and putting in the new circuit breaker without ant deoxy on the wires?

Should the next step be to call the HVAC guy even if the A/C circuit breaker is no longer tripping?

Good job on investigating this.

Was it an actual liquid or more of a paste? Were the wires aluminum?

They put an antioxidant on aluminum wires to help prevent the connection from oxidizing and overheating.

Good job on investigating this.

Was it an actual liquid or more of a paste? Were the wires aluminum?

They put an antioxidant on aluminum wires to help prevent the connection from oxidizing and overheating.

They were silver so I am guessing they were aluminum. It was more of a grey sticky paste. Actually, I just confirmed from my Home Inspection report from last year that this anti-oxidant paste was applied to this exact circuit breaker (from the pictures that I have).

So basically, I am nowhere close to troubleshooting the A/C circuit breaker tripping problem! I just replaced the circuit breaker for no reason and (even worse) removed the anti-oxidant paste that was put in place for protection!! :(

Please guide me on the next course.

1. Should I reapply the paste? I guess I should, eh? Would Home Depot have this?
2. Do I call HVAC only when the A/C circuit breaker trips the next time, or should I do that right away since my circuit breaker has tripped twice in the last 2 weeks?

Thanks,
K

Hi,

It still could have been a bad breaker so give that a try. They do wear out.

Yes, HD should have the paste. Just clean and put it on the terminals. You should be all set.

Do you have an outside disconnect? Can you check that for water/damage? With the power off course.

If the new breaker trips, I'd call the A/C guy. Unless you have reason to suspect the wiring is at fault.

Hi,

It still could have been a bad breaker so give that a try. They do wear out.

Yes, HD should have the paste. Just clean and put it on the terminals. You should be all set.

Do you have an outside disconnect? Can you check that for water/damage? With the power off of course.

If the new breaker trips, I'd call the A/C guy. Unless you have reason to suspect the wiring is at fault.

Should the paste be applied only on the exposed part of the wire or even on that part of the wire which is under the screw?

Regards,
K

Coat the end of the wire and put under the screw.

Pick up an inexpensive clamp on ammeter... you can find one for about $10. Then after you re-apply the anti-oxidant and reconnect the wire, you can check the load on the circuit while running. That will tell you if things are in order. How tight were the connections when you changed the breaker? And next time there is a rain, shut off the main and open the HVAC box and see if it has any water in it. There probably would have been some evidence of mositure when you were looking around in the box if that was the case.

OK guys. My turn.

You mentioned rain. With rain you have power failures while the system is running.

If the system experiences a power failure when running, the surge current in the system can me extremely large. I've seen fuseholders self-destruct under these conditions. The AC is trying to start under high head pressure and draws lots of current trying to do so.

Manufacturer's don't put protection in the compressors where it should be, but rather in the new electronic thermostats. After an off cycle, the tstat usually will not let the AC turn back on again until 2-5 minutes has elapsed.

Replace the tstat with an electronic one or add an anti-short cycle relay to the AC.

Thank you everyone for your replies. So the general consensus from all is:

1. Get the antioxidant paste from Home Depot and apply it to the tip of A/C wires before screwing them in the NEW A/C circuit breaker.
2. Get a HVAC guy the next time the A/C circuit breaker trips because very clearly the problem is not with the circuit breaker AND beyond my troubleshooting realm.

What say?

1. True

2. If your thermostat is not digital and programmable, change it.
You'll get energy savings to boot.

Coat all exposed Aluminum conductors with the paste. Get the GB brand (Gardner Bender) if possible available at Home Depot. This paste is electrically conductive and also stops corrosion on aluminum conductors.

Cut sheet for OX-Gard Grease

http://www.gardnerbender.com/pdf/msds/GB_MSDS_Ox-Gard.pdf

See last page on this pdf for picture

http://www.gardnerbender.com/pdf/products/wire_connectors.pdf

As far as the digital programable thermostat goes if you are not going to use the set back feature for get it.To many people buy these thermostats and never actually use them and if you have a heat pump system they are all but worthless for saving energy. But if not changing the thermostat do purchase a time delay relay (delay on the break type) and wire it into the low voltage circuit for the contactor in the outside unit. Simple to wire and the directions should come with the item.

Coat all exposed Aluminum conductors with the paste. Get the GB brand (Gardner Bender) if possible available at Home Depot. This paste is electrically conductive and also stops corrosion on aluminum conductors.

Cut sheet for OX-Gard Grease

http://www.gardnerbender.com/pdf/msds/GB_MSDS_Ox-Gard.pdf

See last page on this pdf for picture

http://www.gardnerbender.com/pdf/products/wire_connectors.pdf

As far as the digital programable thermostat goes if you are not going to use the set back feature for get it.To many people buy these thermostats and never actually use them and if you have a heat pump system they are all but worthless for saving energy. But if not changing the thermostat do purchase a time delay relay (delay on the break type) and wire it into the low voltage circuit for the contactor in the outside unit. Simple to wire and the directions should come with the item.








Thanks, hvac1000 for your detailed reply.

I shall get the GB brand from HD.

I don't plan to change my thermostat since I have a programmable one. This exact Honeywell model [Model # RTH7600D]: 7-Day Programmable Touchscreen Thermostat - Honeywell Your Home Expert (http://yourhome.honeywell.com/Consumer/Cultures/en-US/Products/Thermostats/Do-It-Yourself/Programmable/7-Day/Touchscreen/Default.htm). Is there some setting here that you want me to change?

Regards,
K

Your thermostat incorporates a 5 minute delay. If the power off condition was very brief, then the delay may not work. I've designed quick responding reset circuits in the past, so I know. Most need at least 50-100 ms to work. My circuit was less than 10 mS.

Under special features in the below link it talks about a wait period which is the time delay function built into your thermostat. You can test this feature to see if it is working by turning on the A/C then turning it back off in a minute or two. Then turn it back on right away and see if the WAIT sign shown on the thermostat and the outside unit is not running. If you get the WAIT sign and the outside unit is not running then the thermostat is working as it should. More than likely your thermostat is working fine and the power off time mentioned by kiss is so short it will probably never happen in real life at your location. We monitor the power generation end at Duke Energy Utilitys at the university for cycles per second variation (CPS), Line Voltage Anomalies (LVA), and almost all other power factor corrections and containment items. We have never experiences a micro second reading so small according to my checking of our computer records this day.

I hope you get it all figured out.

BTW here is a manual that addresses the wait period. Se page 20, and 17.

http://customer.honeywell.com/techlit/pdf/PackedLit/69-2207ES.pdf

Whatever you do forget about using the automatic changeover feature on this thermostat. In most areas it will cost a lot more money on your utility bill for the use of that feature.