Do I have an HVAC issue or an electrical issue ?

Post a pic of name plate. It will list min circuit ampacity and max breaker size.

When it’s running, how does it sound? Could be the fan cap or the fan itself, those are relatively cheap/easy fixes!
This!

You may be fine with #12 NM cable with a higher ampacity breaker.

The breaker serves only for short circuit protection for ACs. The unit itself has internal overloads for the compressor to prevent it from overworking itself.
 
Post a pic of name plate. It will list min circuit ampacity and max breaker size.

When it’s running, how does it sound? Could be the fan cap or the fan itself, those are relatively cheap/easy fixes!
This!

You may be fine with #12 NM cable with a higher ampacity breaker.

The breaker serves only for short circuit protection for ACs. The unit itself has internal overloads for the compressor to prevent it from overworking itself.
You seem familiar with 430-440. ☝️
 
Funny you posted this today. Just this AM I cycled the breaker on our A/C as the fan on the condenser for the first floor wasn’t coming on/and it was 80+ down there. Manually power cycling it did it, so I’ll be ordering a new Starter Cap at the suggestion of a friend of a friend who has an HVAC company since they seem cheap enough.
 
Don't breakers start to get "weaker " the more times they are tripped?
I'm sure there might be more to it, but I'd replace the breaker anyways
Well, yes and no.

The breaker has two separate trip mechanisms. The overload mechanism is based on thermal: the current runs through a bi-metallic coil, which bends with temperature, and with enough current and time, it will trip the breaker. The dead short mechanism is magnetic and it trips immediately.

Aging has less effect on the trip mechanisms than it does on the breaker points. Every trip -- and every actuation of the breaker as a switch -- causes an arc across the points if done under load. The resultant damage to the points will increase the resistance of the breaker, which can in turn alter the breaker's effective overload rating.

Most folks will give you two rules on breakers: (1) don't use them as switches, and (2) replace them if the breaker has tripped a handful of times.
 
Most folks will give you two rules on breakers: (1) don't use them as switches,
Oh, oh.

I use the breaker in my basement to turn the pool pump on and off. It is a GFCI one. Saves tripping around in the dark at night. Maybe need to rethink this?
 
None of this is correct the breaker is tripping for a reason
Breakers never fail? That's not a possibility? And My Condenser is on 30A circuit, OP said his was on 20, most of the systems I have seen (not a lot) have been on 30s as well. Not trying to be a smart ass but I have had many breakers replaced by our electricians simply because they have failed internally in some way, especially those friggin AFCI breakers
 
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Licensed electrician here. I’ve wired condenser’s that range from 20A-50A. The size of the unit is determined by how many BTU’s is needed, with each requiring their own specific amperage. Just upgrading the breaker to a higher amperage could cause an immediate fire if the wire isn’t rated for that breaker.

Palladin and Mr. Brownstone’s comments are 100% correct and necessary for us to move on to your next step.
I second this. Conductors are not based off breakers in HVAC equipment, they’re based off MCA, (minimum circuit ampacity) This is exactly why increasing a breaker size is dangerous unless it matches or is under the MOP.

OP, whats the nameplate ratings?
 
Breakers never fail? That's not a possibility?
Breakers do fail but if they are tripping it’s for a reason and most likely working properly.
In the last 20 years I can count on one hand the amount of residential breakers I have seen fail. When the do fail I mostly see them not close or open properly. I do get a lot of service calls from homeowners that say they have a circuit tripping and they changed the breaker and that did not solve the problem.
 
I second this. Conductors are not based off breakers in HVAC equipment, they’re based off MCA, (minimum circuit ampacity) This is exactly why increasing a breaker size is dangerous unless it matches or is under the MOP.

OP, whats the nameplate ratings?
Never mind, the other sparkeys have this covered...
 
Funny you posted this today. Just this AM I cycled the breaker on our A/C as the fan on the condenser for the first floor wasn’t coming on/and it was 80+ down there. Manually power cycling it did it, so I’ll be ordering a new Starter Cap at the suggestion of a friend of a friend who has an HVAC company since they seem cheap enough.
So I was going to start my own thread asking for HVAC advice but this post is pretty similar to my problems so hoping you all will tolerate me adding my questions to this thread....

5 year old house with Geologix geothermal HVAC ... Overall very happy with it. 2 zones on 1st floor on 1 unit in the basement (pump, air handler.. not sure what you call it) 2nd floor has it's own unit in the attic.

For the past few days the first floor zones just stop working. I can restart them by manually power cycling the unit from the breaker panel. (They aren't tripping spontaneously). When on, they run for a few hours, then stop again, sometimes when they reach the target temp from the thermostat, sometimes prematurely.

When running, the air coming from the vents is nice and cold but the air flow is noticably weaker than normal.

2nd floor on separate unit functions normally.

Sorry for the long post... Just trying to not leave important diagnostic details out and I have no idea what is or isn't important.

Thanks in advance for any thoughts/advice.
 
So I was going to start my own thread asking for HVAC advice but this post is pretty similar to my problems so hoping you all will tolerate me adding my questions to this thread....

5 year old house with Geologix geothermal HVAC ... Overall very happy with it. 2 zones on 1st floor on 1 unit in the basement (pump, air handler.. not sure what you call it) 2nd floor has it's own unit in the attic.

For the past few days the first floor zones just stop working. I can restart them by manually power cycling the unit from the breaker panel. (They aren't tripping spontaneously). When on, they run for a few hours, then stop again, sometimes when they reach the target temp from the thermostat, sometimes prematurely.

When running, the air coming from the vents is nice and cold but the air flow is noticably weaker than normal.

2nd floor on separate unit functions normally.

Sorry for the long post... Just trying to not leave important diagnostic details out and I have no idea what is or isn't important.

Thanks in advance for any thoughts/advice.
Ever changed the filters in the air handler?? If no, change them.
 
All I know is the OP better not leave us hanging here!!!
Apologies for the slow response guys....didn't realize I was kicking off a "My A/C Shit The Bed" mega thread ;-)

Ok, it's a *30* amp circuit feeding the condenser, not a 20....not sure how that slipped by me while typing. Attached a pic of the plate/label on the unit if anyone thinks it's still relevant given this new info. I was away this weekend, so no in depth trouble shooting performed. I continue to "use the breaker like a switch"...sometimes it's a few times a day, sometimes it a lot of times a day....no rhyme or reason. Woke up this morning @ 2:30AM feeling clammy...down to the basement I go ;-)

As I mentioned briefly, the unit has barely shut off (normally) throughout this bullshit Louisiana swamp weather we're been experiencing...so it's not a matter of tripping the breaker when the unit spins up...as it almost never spins down...until the breaker trips.

I'll give it a closer look tonight if I can get out of work at a decent hour.
 

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Apologies for the slow response guys....didn't realize I was kicking off a "My A/C Shit The Bed" mega thread ;-)

Ok, it's a *30* amp circuit feeding the condenser, not a 20....not sure how that slipped by me while typing. Attached a pic of the plate/label on the unit if anyone thinks it's still relevant given this new info. I was away this weekend, so no in depth trouble shooting performed. I continue to "use the breaker like a switch"...sometimes it's a few times a day, sometimes it a lot of times a day....no rhyme or reason. Woke up this morning @ 2:30AM feeling clammy...down to the basement I go ;-)

As I mentioned briefly, the unit has barely shut off (normally) throughout this bullshit Louisiana swamp weather we're been experiencing...so it's not a matter of tripping the breaker when the unit spins up...as it almost never spins down...until the breaker trips.

I'll give it a closer look tonight if I can get out of work at a decent hour.
You should have #10 conductors on a 40A breaker.

Low refrigerant can also cause it to overwork itself if it hasn’t been checked in awhile.
 
Another vote for the start or run cap. On an old (1970s vintage) industrial HVAC unit we would actually have an internal breaker trip because a resistor on the 40 year old through-hole soldered circuit board was loose. Re-soldered it and it ran like a top.
 
It's 12 yrs old....ever clean the condensor coil? Put your hand over the condensor when it's running, the air coming out should feel warm but not hot. If it feels hot your coil is dirty and your head pressure is running way high. Running with high head will trip the breaker because the compressor is working hard. Sometimes when they are dirty you can hear the air pulsating through the condenser and the fan will bounce on the stamped metal tops. Weather will be cooling down on Wednesday, see if the breaker stops tripping.
 
The sad part, 20 - 25 years is the life expectancy for central AC systems. Just had mine serviced a couple months ago, "just so you know, you have like 5 years left on these" Just what i wanted to hear on 2 large carrier infinity systems.
That's crazy.
We have a commercial building with ~7 separate systems.
4/7 have the original Williamson Condenser / compressors from the early 1980s, over 35 years old.
7/7 have the original Williamson Air Handler Units from the 1980's.
My HVAC guy happily just keeps replacing small parts off of them when they break.
I guess he knows, some day, the place will be a gold mine when I finally have to replace them. [laugh]
 
Hose out the condenser coils. Dont need a lot of pressure, garden hose is fine. Turn power off and gently spray water through the coil

I will confess that I did not clean mine for 15 years out of ignorance. A few YouTube videos later I had the top off to get all the crap out of the inside, sprayed it from the inside out to clean a bit, use special A/C coil cleaner from Amazon for $25 a can, rinsed well and all back together. I had the cap fail and replaced 5 years ago and learned the hard way to turn on the A/C the first hot day in May to make sure it works and get a service person if needed. I imagine a service call today would have the person show up just in time to clean the snow off.
 
That's crazy.
We have a commercial building with ~7 separate systems.
4/7 have the original Williamson Condenser / compressors from the early 1980s, over 35 years old.
7/7 have the original Williamson Air Handler Units from the 1980's.
My HVAC guy happily just keeps replacing small parts off of them when they break.
I guess he knows, some day, the place will be a gold mine when I finally have to replace them. [laugh]

R22 - they likely cool better than a new unit. Also those sound like baack when things were engineered to work. Today everything is engineered to just barely work at the lowest possible cost point and just long enough to get through the warranty.
 
28.4 amps on a 30A breaker ......should be on a 40A. Inrush current is 34A minimum
Meh, 28.4 is minimum circuit ampacity, not full load. 40 would be fine but I don’t think that’s the problem.

It could be contactor/fan/cap/even a failing safety switch. I would inspect all those first, but without eyes I think you need an hvac tech.

If it’s tripped a bunch of times recently, replace the breaker even if it doesn’t need to be.

Shit, it could be failing bus bar behind the breaker, I’ve been embarrassed by that before!!
 
It's 12 yrs old....ever clean the condensor coil? Put your hand over the condensor when it's running, the air coming out should feel warm but not hot. If it feels hot your coil is dirty and your head pressure is running way high. Running with high head will trip the breaker because the compressor is working hard. Sometimes when they are dirty you can hear the air pulsating through the condenser and the fan will bounce on the stamped metal tops. Weather will be cooling down on Wednesday, see if the breaker stops tripping.

Never cleaned the coil.....I would call the air coming out as *very* warm.
 
Oh, oh.

I use the breaker in my basement to turn the pool pump on and off. It is a GFCI one. Saves tripping around in the dark at night. Maybe need to rethink this?
Some are switching duty rated. I think all the Cutler-Hammars are SWD.
 
Meh, 28.4 is minimum circuit ampacity, not full load. 40 would be fine but I don’t think that’s the problem.

It could be contactor/fan/cap/even a failing safety switch. I would inspect all those first, but without eyes I think you need an hvac tech.

If it’s tripped a bunch of times recently, replace the breaker even if it doesn’t need to be.

Shit, it could be failing bus bar behind the breaker, I’ve been embarrassed by that before!!
Contactor would do it. Troubleshot one the other day where the breaker was tripping multiple times a day.

Breaker was junk and the contactor’s contacts had evidence of arcing/high resistance connections.

Opened the breaker and it was very obviously overheated many times and the busbars had some heat discoloration so moved it elsewhere in the panel.

You may also want to see what sort of rebates you can get from MassSave. I think they’re doing 75% rebate off certain size units or something, which is huge.
 
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