Some friends of ours called today and had an unusual issue. Earlier this morning they had their upstairs HVAC system running for some heat, and two kids back-to-back showers. The dad happened to hear a slight hum coming from the laundry room where the breaker panel is located. He found it coming from the breakers, but it quit before he could find the exact location. Also, he found the hot water heater 220 breaker was almost too hot to touch. I went over to have a look. He tried to make the sound happen again and recreated the conditions but nothing. First thing I noticed was (there are two HVAC systems, upstairs and downstairs) two double 60amp breakers and two 30 amp breakers. He had mentioned a Home Inspection had hinted to him something about those breakers “wasn’t right”. I thought they were a bit too heavy, so I looked at the tags on the units—both Tranes from about 2006–and one tag noted max fuse of 30 amp and the other noted 20amp. Supposedly this house was built in 1991 and the breakers could be that old as far as he knows. I’m sure that there should be the 30 and 20 amp breakers instead of the 60s, but I plan on contacting Trane for maybe a confirmation. As far as the air handler, I don’t have a clue what they are or specs at this point…
On the water heater breaker (30 amp double) he had noted that earlier this morning he had touched it, and it was almost hot enough to burn fingers. I found an unused matching breaker and swapped it, thinking that the old breaker was weakening. Was doing fine when I left, and I believe my little cheap amp meter didn’t show anything high to be alarmed about.
How does this scenario sound? Again, many thanks for advice, hints, chastising, etc.

 

I did also check for tightness of screws in all the double breakers and found about 3 just slightly loose, maybe an eighth of a turn to tight.

 

Time for a clamp-on ammeter check, see what the actual load is, if within a suitable number,
For a start anyway!

 

Time for a clamp-on ammeter check, see what the actual load is, if within a suitable number,
For a start anyway!

With my little cheap HyperTough clamp ammeter, I got about average of 18 amps.

 

Following morning, when the upstairs heat pump was running the sound was back. I don’t believe he was able to pinpoint exactly where the noise was but I believe it had to be from the 60amp breaker, since it only sounded when the unit was running. I’m not able to attach video but I heard it and it’s a “constant buzzing” that sounds when the unit is running…

 

It is probebly wise to to take the precautionary path at this point and replace the breaker!

 

UPDATE: last night I dug into the panel. Had to spend a lot of time reassessing the panel, units, etc. Ended up being mistaken about which breakers were associated with which units. Found that each condenser unit had 30 amp breakers—not 60s. But the air handlers had the 60s on them. So I changed out the condensers to a new 30 and a new 20. (Went by the requirements listed on the tags)
Could not easily get to the attic unit to look at, but managed to struggle under the house to see the other. Found that it was labeled American Standard from 1991, and contained two breakers, a 25 and a 60 amp. But the 25 was turned off. Doing more “testing” and found the Emergency Heat position on the thermostat did not produce any heat, so we assumed that OFF breaker was associated with it. So with that, we left things as they were…my main focus was on that buzzing (again only at a few time periods, in mornings) so I figured the old breakers needed freshened up anyway. So far so good. The new water heater breaker I had installed a couple days back was fine—no heat on it whatsoever…
Probably won’t be long and may be looking at replacements for these 91 and 06 year units…a home inspection a couple months earlier had revealed a ton of problems or concerns and looking closer last night, I was shocked to see the actuality of them. Looks like the builder did a lot of shoddy things and maybe the previous owners. My poor friends don’t have a clue about most of it but willing to learn. Luckily, they have a close friend that is a real electrician, and he’ll start helping them fix a lot of things with their sweat equity.
Thanks to all of you again.

 

Congrats on having a '91 still in running if it still is. a lot of reasons for a buzzing breaker.
if the motor run caps are bad the compressor or blower motors will draw a lot of current
until the motor fries. The emergency heater is all electric and runs when the heat pump
can not meet demand. they typically will draw 30, 40 or 50amps depending on size if the
heating system. based on your breaker comment about the larger breaker being on and
the smaller 25A being off it is possible that the system no longer works and you are heating
with just the electric heaters which would be bad. That '91 unit is probably not higher than a
10SEER unit with HSPF around 6-7 replacing with a new Trane high efficiency 18-20Seer unit
and matching variable speed air handler will pay back the upgrade expense in electric costs in
just a few years.
Your '06 is 20 years old and probably nearing its end of life. Heat pumps generally last between
15-25 years. My builder put in too mall units in originally and the downstairs unit dropped dead
in 15 years the upstairs unit failed at 19 years but they used to run really long to meet temperature.
Those 60A breakers may be bad also but best to get a current clamp measurement to see that it is
not buzzing because the load is near maximum. My two Trane units pull 15A each when running on
a 208 service and electricity cost nearly half going from one 10 seer and one 12 seer Rheem unit to
two Trane XL18i's when I upgraded. Now they make an XL20i they have been running flawlessly with
annual maintenance so I can recommend Trane highly.

 

Congrats on having a '91 still in running if it still is. a lot of reasons for a buzzing breaker.
if the motor run caps are bad the compressor or blower motors will draw a lot of current
until the motor fries. The emergency heater is all electric and runs when the heat pump
can not meet demand. they typically will draw 30, 40 or 50amps depending on size if the
heating system. based on your breaker comment about the larger breaker being on and
the smaller 25A being off it is possible that the system no longer works and you are heating
with just the electric heaters which would be bad. That '91 unit is probably not higher than a
10SEER unit with HSPF around 6-7 replacing with a new Trane high efficiency 18-20Seer unit
and matching variable speed air handler will pay back the upgrade expense in electric costs in
just a few years.
Your '06 is 20 years old and probably nearing its end of life. Heat pumps generally last between
15-25 years. My builder put in too mall units in originally and the downstairs unit dropped dead
in 15 years the upstairs unit failed at 19 years but they used to run really long to meet temperature.
Those 60A breakers may be bad also but best to get a current clamp measurement to see that it is
not buzzing because the load is near maximum. My two Trane units pull 15A each when running on
a 208 service and electricity cost nearly half going from one 10 seer and one 12 seer Rheem unit to
two Trane XL18i's when I upgraded. Now they make an XL20i they have been running flawlessly with
annual maintenance so I can recommend Trane highly.

Wow! Thanks for the great info. I’ve told them too, that I think they need to be preparing for replacements, as these have served their time, and could quit at any time. But that’s a financial hurdle for them so it’s going to get interesting. They do have one thing in their favor—they have a good friend who’s a bonafide HVAC guy, and can do all the work for them. (I suggested some good dinners for him and to add their own sweat equity )
I’m still puzzled with the downstairs unit and its air handler in the crawl space…when the pump thermostat is turned on to normal position I feel the usual “lukewarm” heat at the registers. But in the Emergency Heat mode we get nothing but cool air (after turning on the fan.)
Maybe it has a small strip that is supposed to run on that 25A breaker? Seeing what I’ve seen on a lot of other stuff I don’t know what’s “normal” on these units…
So far, the two new 30 and 20A breakers installed everything is fine and no noises. I’m going to suggest they get their friend the pro to come take a deeper look.

 

Heat pumps generally last between 15-25 years.

I live in Phoenix. Our home must be magic or something. Built in 1973. A heat pump that heats/cools an addition that was probably built in the 1980s or early 90s.

It literally cools one room that is about 30x20x8 feet in size; due to where and how the addition was built, they couldn't run ducting from the main house unit - so what I think they did was move the old house unit to the addition, and then put in some kind of swamp cooler in place of that, for the rest of the house.

Then at some point, they switched the swamp cooler back to a heat pump; that heat pump is newer, from sometime in the late-1980s to early 90s. Obviously I'm not completely sure about timing; for all I know that heat pump was used when they bought it.

That old heat pump was from the 70s, because it still has it's original paint job: Classic Avocado Green.

I know this color well, because it was the color of my parent's house which was built in 1971 (they later had it stucco'd and repainted in the 1980s - to a weird yellow and mica flake; strangely, we didn't have the popcorn ceiling/mica flake look - just the popcorn - they also removed the loose rock roofing that was popular in the 60s and 70s and replaced it with asphalt shingles).

That - and the tag shows it was a 1973 model, same age as the house. We bought the house in 2002. In that time, the only problems we've had with that old '73 Goettl has been it needing a new run capacitor for the interior blower motor. It has no leaks - if it ever did, we'd need a new unit - because it runs R12.

The other unit, we've had to replace a couple of delay relay/contactors in it - and that's it. It likely also needs a new fan motor, as our service guy said it was pulling a bit high of current, but we couldn't afford to replace it at the time...that was 3+ years ago. I keep thinking I'd go up there and pull the panel off and squirt some 3-in-1 motor oil on the bearings (probably oilite, so it should soak it up); it isn't anything outside of what I can do (I replaced the relay that died the first time, but it was in cooler weather; the next time I called for the service, and diagnosed it being the same relay from inside the house with the interior wiring diagram - but it was the middle of summer, and a rooftop in 120 degree heat was worth paying someone else for).

I always make sure the breaker is off and pull the fuses off the side so there is zero chance of any kind of surprise death happening. Really, the trouble with doing anything on these units - is getting the parts; here in Arizona (and probably elsewhere) - they'll only sell parts for HVAC systems to licensed repair people. I get why they do it...but most of these old units are just relay logic for the most part; and as long as I don't go stupid trying to flame solder on the coils (and potentially unaliving myself with an accidental phosgene exposure)...the only other danger is mainly electrical (or being stupid enough to leave the electrical connected, and stick a part of my body into a spinning fan or something).

Anyhow - I found ways around that back then (sometime in 2004 or 5?) - but nowadays, many if not most parts can be bought on Amazon, and I don't have to go to a specialized AC parts shop.

So yeah - my systems or home must be magic - because all of it is 40-50+ years old, and all running mostly great. I have no desire to replace any of it - because every person I know who has done such a thing - either to save money in manner, or because they had no choice - seemingly needs to spend money on repairs every year or two.

Oh - and the first time we had that run capacitor problem on the Goettl unit - I called the company (local to AZ), explained to them what the problem was, told them I had the installation paperwork with the mechanical drawings and wiring diagram - and they told me they had nobody who could fix it. We ended up calling a cheap 24/7 repair guy who had it running in about 12 hours; he told me it was the run capacitor, but that he had to wait until morning to get a new one. I went on the roof with my meter (at night, when it was -only- 105F), made sure the power was off, and checked the capacitor myself - and it was bad. So I knew he was legit.

He fixed it, parts and labor were decent, considering his time and effort and the heat - and I had no problem paying it. That was probably 15-20 years ago, no other problem with the green monster since.