Battery Powered 2 Ton AC

JUGHNE

No AC call late last night.
Owner said he put new fuses in disconnect and still no go outside.
Went there today and looked at the 30 amp cartridge fuses.
They said "Duracell" on the label!!
He did say he could not find any AA fuses in his collection that were time delay.

The batteries did test good at 1.58 VDC. They fit perfectly into the fuse clips.
But no continuity as they have a plastic wrap on them, fortunately.
Without the wrap they may have run the AC until the clips heated up.
Luckily the 2 ends of the AA were not touching the fuse clips.
If so that may have been an explosion as he pushed the pull out back into the box.

He might be +80ish, maybe a minor stroke in the recent years.
He is of the type that is handy and "fixes" everything he can.
I will talk to his son about this soon.

But 1982 Lennox still running good, both caps test good, contactor OK and
cond fan motor seems originial. A weakness in these units was the compression
O ring connections at the line set hook up, they would usually be leakers.
But added only 1/2 LB of R 22 so not too bad.
Would any AC we install today be still running after 38 years, without repairs?
My guess is no.

SlamDunk

GASP!

ChrisJ

Wow.

JUGHNE

He also had a lattice cover (about 6" squares, quite open design) around the unit with lattice top cover.
You could hear the air flow disturbed when I put it back on.
Had the owner watch the high side with it on and off.
Without cover 245 PSI.......with cover 290 PSI.
This is with clean coil and only 85 amb air temp.

He washes the coil himself once or twice a year, back flush from inside out.
I explained again, carefully, to pull out the disconnect....do not assume it is off by the tstat......he has a single pole contactor.
I drew him a simple plan to show that every wire in the unit is still energized, he understood it........today anyway.

mattmia2

The outer casing of the battery is probably more than enough to conduct the starting and running loads of the condenser if the label wasn't on it...

JUGHNE

Probably, if the steel was really clean. But they go into brass clips and might over heat eventually. Unit pulls about 14 amps.
But it is not impossible that the "AA" fuse/battery positive tip come in contact with the brass clip.

Also noticed a 1 1/2 KO open in the side of his meter socket.
It has some straw/string hanging out of it.
That is the attraction hole size for Purple Martins.
Pulled the meter and cleaned out a well compacted nest built around all the lugs. No cooked birds, just dry nest material.
Fortunately, the birds found no foil or tinsel for nest material.
Did install a KO plug.

I have seen pictures of bird nests build out of barbed and bailing wire. This was during the 30's dust bowl when nothing grew.

ChrisJ

I mean......
I'm betting the AA batteries would be fine.

But there's supposed to be fuses in there..............to protect things and stuff.

ratio

I was in a job once, a half-dozen or so rooftops, the plumber has turned the gas line horizontal right out of the unit & slotted the door to slide down over where it entered the unit. I called 'em bird condos. I pulled a 5 gal bucket of dried grass etc. out of the burner compartment of each one. Surprising to me, only one showed signs of burning.

I shut off the gas, turned off the valve & pulled the heat calls; then spent a week or so trying to convince them to do something about it.

JUGHNE

Usually I do not put fuses anywhere unless absolutely required.
Had I wired this originally, I would have put a 25-30 CB in the main panel, run 10 or 12 romex, and then a non fused disconnect at the unit. Simplest troubleshooting and fuses are quite expensive and just more stocked items to have.

But, well meaning family member does the electrical work for the old couple. So the new (too small, only 20 spaces) CB panel is full. Then a 240 circuit added to feed free standing garage.
Install a new 60 amp for the garage, cobble in the existing AC # 10-2 romex on the 60 also........this is definitely beyond the allowed 25' tap rule, which is another discussion in itself.

So the 30 amp fuses at the disconnect are a good thing and needed there.
There is a fair amount of this hack work around here and probably everywhere else.

EBEBRATT-Ed

Think 1/2" copper tubing will fit the fuse clips in an emergency lol

My old boss was an electrician and was home asleep. It was just before Thanksgiving and the turkey farm down the street called him out for a blown 200 amp fuse. They were processing turkeys and needed power.

He pulled his clothes on and not having a fuse cut a piece of copper tubing pounded it down flat and jamed it in the fuse holder.....then went back to sleep

HVACNUT

You can tell it's old when it's a fused disconnect and not a pullout or breaker. The system is more like the Energizer Bunny.

ChrisJ

> @HVACNUT said:
> You can tell it's old when it's a fused disconnect and not a pullout or breaker. The system is more like the Energizer Bunny.

They still sell and use fused disconnects.

HVACNUT

> @ChrisJ said:
> They still sell and use fused disconnects.
>

Of course they do. Just saying by me on LI, it's breakers or pullouts. It's rare for me to see a fused disconnect on a residential condenser up to 5 tons. Thought that was everywhere. Guess not.

JUGHNE

You have to remember that this was 1982 or so.
Non fused disconnects were not as common as now.
Also the cable feeding the disconnect is CBed at 60 amps.

There was older equipment that stated fuses for protection....CB's were not an option.
Eventually HCAR breakers were developed and the AC people caught up with this advancement in design.

Another unheard of today installation practice was to run 600 volt conductors in the power whip with tails going thru the wall with the cable into the basement. The 18-2 was connected in the basement to the tails.
Then in the AC unit you would wire in a standard toggle wall switch to kill the 24 volts. You would tape up the screws on the switch to avoid any contact with hots or ground.
This was considered a legal disconnect for the AC in the early 70's. Did this many times in the city that had inspections.
Of course all contactors were 2 pole so the only hot was on the top lugs. To change contactor or water wash the coil you would/should have to go to the basement and shut the CB off.

So safety has come a long ways...It takes a lot of kicking and screaming to get something like this changed in the NEC.
A lot of dogs in the fight......electricians want to sell disconnects.....HVAC probably wanted them unless it was in their bid price then not a good idea.......real estate sellers want nothing to raise the price of a house that the customer can not see.....they want countertops, flooring etc for selling points. A disconnect would not impress any buyer.
Real estate people were initially against GFCI breakers/outlets, multiple interconnected smoke detectors and still, and probably always, against residential fire sprinkler systems....no glitter in those things.

JUGHNE

I talked to the homeowner's son today, told him the story and it was depressing to him. His dad was one who could clean the flame sensor, change the HSI and knew when the air inlet of the furnace would frost over causing no heat. Also cleaned the ice machines in his businesses.
I recall him calling for no heat a couple of years age and shortly called back saying it was the batteries in the T-stat. That made the furnace work. I am thinking he remembered weak batteries would stop the furnace from working. But was able to test a fuse with an ohmmeter last night to find the bad one.
Him with the knowing of the need for fuses and the previous need for batteries combined the 2 issues. The fuseholders looked like they would accept batteries and this all came about.

The son said that dad is going to a doctor tomorrow about this.
The old couple have 3 of their children living in this little town.
They will probably be more diligent of the situation from now on.

As this happens with old ageing, if you are around someone nearly every day you do not notice the slippage.
And I learned from personal experience with my mother that at certain stages of this progression the mind becomes quite sharp and is able to produce answers that seem to be coherent.

But coming upon this situation with the batteries there could be no logical answer.
I hated to tell the family this but the son does appreciate the heads up.
(This is what you do in a small town).
I have called other kids who's 90+ father was storing tupperware in the oven and could have easily have turned it on.
Or grandma has a serious leak in the basement she never visits.
Or grandma is told she needs a complete new 7K system and it is only a blower motor. She is 90 or so. ROI?

mattmia2

What makes a breaker hacr rated?

I think the fused disconnect is still cheaper to install than the circuit breaker enclosure, especially if you buy the cheapest you can find.

mattmia2

oh, there it is:
https://www.mikeholt.com/forum/Forum1/HTML/004078.html

basically it has a standardized trip curve. older units marked for fuses were only tested with fuses because fuses had standardized curves.

SlamDunk

The family, usually, appreciate the extra eyes on the situation even if it tough to hear.

My wife and I found a little old lady wandering the neighborhood looking for a cemetery we never heard of. Clearly had dementia. It took awhile to find where she lived but we got her there and found she lived alone. We went through her things and found a niece's number and told her what was going on. The niece cried but was grateful. She took care of the lady and sold the house.

ratio

SlamDunk said:

The family, usually, appreciate the extra eyes on the situation even if it tough to hear.

My wife and I found a little old lady wandering the neighborhood looking for a cemetery we never heard of. It took awhile to find where she lived but we got her there and found she lived alone. We went through her things and found a niece's number and told her what was going on. She cried but was grateful. They took care of her and sold the house.

Thanks for doing that.

SlamDunk

Could have easily been my Mom. She suffered from dementia too.

jumper

I'm not an electric guy. I use redundant shut offs for piping. And I recommend redundant safeties like low level, max temperature,etcetra. So perhaps multiple fuses/breakers and shut off for electric is not so crazy. Look funny in belt plus suspenders but pants don't fall down. I s the issue with batteries that conductivity is too high or too low?

JUGHNE

They are wrapped in a tough plastic sheath.

mattmia2

The nec has a rule requiring "coordinated protection", which requires if there is a fault that the downstream device opens. Hard to do that when you have equal rated circuit breakers or fuses on the circuit.

EBEBRATT-Ed

Breakers can do some wonky things. Fuses are a little more straight forward but it's a problem if you don't have spares available.

I have seen specs for jobs with fuses that requires spare fuses to be included in the bid. I sometimes leave a spare set of fuses and just charge for them.

Fuses are much better for high interrupting capacity at a much lower cost than breakers

ChrisJ

> @EBEBRATT-Ed said:
> Breakers can do some wonky things. Fuses are a little more straight forward but it's a problem if you don't have spares available.
>
> I have seen specs for jobs with fuses that requires spare fuses to be included in the bid. I sometimes leave a spare set of fuses and just charge for them.
>
> Fuses are much better for high interrupting capacity at a much lower cost than breakers

I think fuses have two problems.

#1 People.
#2 they blow for no reason if used close to their rating.

I've always preferred them.

JUGHNE

I certainly agree with #1.

#2 can happen when the fuse clips get hot, lose their temper, get hotter then that heat is conducted into the fuse.
Or if time delay and has been "punched" too many times by hard motor starts.

ChrisJ

> @JUGHNE said:
> I certainly agree with #1.
>
> #2 can happen when the fuse clips get hot, lose their temper, get hotter then that heat is conducted into the fuse.
> Or if time delay and has been "punched" too many times by hard motor starts.

If you look up data sheets to fuses you'll see what I'm talking about

The cartridge fuses you use are already sized for the load. When you're choosing glass fuses etc for a circuit you can't just go by the current. If you run a 8a fuse at 7a it won't last long.

Point being, even one sized properly will likely fail after years for no reason were a circuit breaker will not.

To me that's not a deal breaker but it is a negative of fuses.