help with home a/c and circuit breaker

[BigTroll]

while I was gone today the women called me and said the a/c isn't working and the breaker is buzzing so she turned off the breaker. The a/c is a old 1993 model York so its nearing the end of its days, on really hot days the a/c will trip the breaker.

I visually checked the cap and contactor and they looked okay, I also pulled the 250v ac fuses and switched the main ac breaker on and got no buzz. I did get buzz when I put the ac 250v fuses back in and flipped on the breaker nothing but buzzing. could it be a shorted wire or did the circuit breaker just finally give up the ghost?

how hard is the breaker to replace if that is the problem I noticed its a 30 amp breaker on a old murray panel.

[Curious.George]

Re: help with home a/c and circuit breaker

how hard is the breaker to replace if that is the problem I noticed its a 30 amp breaker on a old murray panel.

Most breakers are relatively easy to replace. The first hurdle is almost always FINDING a replacement as panels are often older than "spares supplies"!

Usually, the hot ends of the breaker will clip onto a bus bar in the panel while the load ends are (obviously) discrete wire pigtails that connect to the breaker under a screw.

With this in mind, you'd first turn off the thermostat (no chance of it calling for cooling). Then, open the breaker to ensure the load side connections are "safe". (you can open the MAIN, as well, if you are nervous). Then, "unclip" the old breaker. Now, even in the event of a shorted breaker, you KNOW the load wiring is "safe"! Disconnect the two load pigtails (note which goes where though there is usually no significant difference on most 240VAC BALANCED loads).

Connect the two pigtails to the new breaker. OPEN the new breaker (!!!). Clip the new breaker in place. Dress the pigtails and any wiring that you may have disturbed in the process (take care as there are live connections there!). Then, close the breaker. Turn on thermostat.

[sam_sam_sam]

Re: help with home a/c and circuit breaker

You need to check the UF on the capacitor for the compressor it might be low or none at all use a capacitor checker not a ESR meter this might not help you

[CapLeaker]

Re: help with home a/c and circuit breaker

You need to check the UF on the capacitor for the compressor it might be low or none at all use a capacitor checker not a ESR meter this might not help you

that's where I'd go first. Replace that AC starting capacitor.

[ChaosLegionnaire]

Re: help with home a/c and circuit breaker

yea, what if u replace the breaker but the buzzing sound still persists? i'd check first to see if the buzzing sound occurs only when the ac is on. if so, it could be some electro-magnetic resonance from one or more of the ac fan motors causing the breaker to buzz.

[eccerr0r]

Re: help with home a/c and circuit breaker

I visually checked the cap

I visually checked the Fuhjyyu and it looked ok, so it must be fine...

[BigTroll]

Re: help with home a/c and circuit breaker

Circuit breaker is okay actually as soon as you turn the circuit breaker on the ac is buzzing also and my friend saw electrical sparks that looked like the end of the evaporative coil going to the chassis I think the compressor might have a internal short so I was thinking of pulling the red wire to the compressor and applying power to see if it still getting chasis electrical shorts.

[BigTroll]

Re: help with home a/c and circuit breaker

I visually checked the Fuhjyyu and it looked ok, so it must be fine...

anyway I can check it with just a harborfreight centech multimeter I honestly don't know how to check caps. also it is a gentech which I guess was a spinoff of GE so its a decent quality cap I put it in 4 years ago.

[stj]

Re: help with home a/c and circuit breaker

the centec afaik does not test caps well

[sam_sam_sam]

Re: help with home a/c and circuit breaker

How long compressor capacitor last depending on how bad your electrical supply is coming from the power supply company

If you have a lot of brown outs - voltage spikes and the like these of capacitor do last long
Also depending on what country these capacitors can also make a difference how long they last

Where I work I had replaced the compressor capacitors about 3 or 4 years ago and just recently they had to be replace again because the power supply company gives us not very clean supply voltage dipping voltage spiking and what ever else

These capacitors were made here in the USA

This why I made the comment earlier that you need to check the UF value of this capacitor and if it lower than 5% replace it I would replace them if they were 2% lower in value

The problem when the capacitor UF drops it causes a couple of things to happen
One is if value drops a little bit it can cause the compressor motor to run hotter than normal and in some case if it is a dual capacitor it can cause the fan motor to run hotter than normal and shut down

If the value goes down enough it can cause compressor to not always start reliably each time and causes the fan motor to overheat

[Logistics]

Re: help with home a/c and circuit breaker

I have been humorous the idea of replacing my breaker as it looks old, and it's not difficult to trip as my entire apartment is a single 20A breaker so if the air conditioning is on, the fridge can run, but if I use the microwave it breaks, if I have the rice cooker or instant pot running with the AC, the microwave will make it break even faster obviously. And naturally all.those kitchen appliances are at the very end of the circuit.

Is there a rule of thumb for good brands to replace breakers with? I'm in California mind you so I won't be able to source brands from you out of country chaps/mates.

[budm]

Re: help with home a/c and circuit breaker

Are you sure your entire apartment has only ONE 20A circuit breaker.
You are over loading the circuit with all those loads.
The surge current for the AC and the Fridge can be 3 ~ 5 times running current.

[Curious.George]

Re: help with home a/c and circuit breaker

I have been humorous the idea of replacing my breaker as it looks old, and it's not difficult to trip as my entire apartment is a single 20A breaker so if the air conditioning is on, the fridge can run, but if I use the microwave it breaks, if I have the rice cooker or instant pot running with the AC, the microwave will make it break even faster obviously. And naturally all.those kitchen appliances are at the very end of the circuit.

You may find that you actually have TWO 20A circuits -- if it's a duplex breaker. It's not uncommon to run a 3-wire "240V" feed around a small apartment and wire half of the loads to "one leg" with the other half on "the other leg".

Is there a rule of thumb for good brands to replace breakers with? I'm in California mind you so I won't be able to source brands from you out of country chaps/mates.

You likely won't have much choice in the matter. Every panel is slightly different. So, a breaker that isn't intended to fit your panel simply won't fit! (they may be electrically compatible but not MECHANICALLY)

[sam_sam_sam]

Re: help with home a/c and circuit breaker

This is very important

“ You likely won't have much choice in the matter. Every panel is slightly different. So, a breaker that isn't intended to fit your panel simply won't fit! (they may be electrically compatible but not MECHANICALLY)”