Window a/c tripping breaker on dedicated line

[K8MHZ]

Some thoughts here-

If you have some kind of "start assist" wouldn't you actually increase the initial demand --- but since you have faster acceleration it would be for less time. Kind of robbing Peter to pay Paul kind of thing.

Also wouldn't a worn compressor have more "slip or leakage" in the compressed media making it actually demand less torque to get it started? Once running it may not perform to original specs and is probably less efficient than it once was but would probably be easier to start. Now if a bearing is what is worn, that will add load, but will also continue to get worse and eventually cause thermal failure of something.

What does having a clean condenser coil have to do with starting current? High pressure in the condenser because of a plugged coil will not happen until it has been running long enough to build such pressure, starting is over with long before this kind of pressure is reached.

A compressor with worn internals may be pooling oil. Trying to pressurize oil until it's dispersed will increase inrush current.

Usually, the bearings in the compressors wear, causing parts that were not meant to touch to do just that.

We also have the motor to think about. Besides bearings, it's entirely possible that the winding's insulation may be losing integrity.

A plugged expansion valve may cause the compressor to have to work harder, too. Without a place to connect gauges, there is really no way to check for a partially plugged valve. One completely plugged off will cause the unit not to cool air.

And let's not forget about the motor that drives the fan. If that is at it's end of life and drawing too much current, that will add to the inrush of the compressor motor for total current at the OCPD.

None of the above is really repairable. Small AC units are not made to be repaired or have any scheduled maintenance done on them. There is no place to add or release the freon and thus, no place to measure pressure or check for oil.

 

[K8MHZ]

And the newer one is going to be more efficient. 10 years newer may not pay off as fast from energy saved as one that is 20-30 years newer though.

I just bought a 10k for about 200 bucks. It's very efficient and blows literally ice cold air. There are two downsides to the new units. One, they don't remove as much humidity as the older ones do, and two, they are quite loud. Mine is so loud I have to put it in the kitchen as it's hard to hear the TV over it. But, it works so good it easily cools the living room which is adjacent to the kitchen.

 

[kwired]

I just bought a 10k for about 200 bucks. It's very efficient and blows literally ice cold air. There are two downsides to the new units. One, they don't remove as much humidity as the older ones do, and two, they are quite loud. Mine is so loud I have to put it in the kitchen as it's hard to hear the TV over it. But, it works so good it easily cools the living room which is adjacent to the kitchen.

Maybe you have a unit that is oversized for the application? If it is not dehumidifying enough then it must be reaching setpoint temperature too quickly leaving the room cool but clammy.

Another disadvantage of a self contained unit like that is the supply and return air are so close to one another you do not get circulation through the room like you will with a well designed permanent installation. The larger the area you are trying to condition the bigger this problem becomes.

 

[StarCat]

Hard Start Gear

Hard Start Gear

Single phase hard start gear is very often installed on split systems. It is not really a trade off, they do lower the peak current and reduce starting time.
They are either PTC, or potential relay and start capacitor.
Some window ACs have PTCs from the factory, but not commonly.
Window AC units in this age are not TXV systems but fixed restrictor type.

 

[kwired]

Single phase hard start gear is very often installed on split systems. It is not really a trade off, they do lower the peak current and reduce starting time.
They are either PTC, or potential relay and start capacitor.
Some window ACs have PTCs from the factory, but not commonly.
Window AC units in this age are not TXV systems but fixed restrictor type.

Does it really reduce peak current?

I have never really checked it out for certain. Logic tells me that since you are in effect increasing the acceleration time that you will increase peak current, but you also are reducing the duration which may be what actually keeps you from tripping breakers.

You are making the same acceleration in less time so the same work is done in a shorter time, the voltage doesn't change (disregarding voltage drop) so the extra input needed to get power out has to come from increased current.

 

[K8MHZ]

Maybe you have a unit that is oversized for the application? If it is not dehumidifying enough then it must be reaching setpoint temperature too quickly leaving the room cool but clammy.

Another disadvantage of a self contained unit like that is the supply and return air are so close to one another you do not get circulation through the room like you will with a well designed permanent installation. The larger the area you are trying to condition the bigger this problem becomes.

I think it's the new design, which uses the water from the humidity in the house to cool the condenser. Instead of just draining out, it pools up about a half inch and allows the fan to mist the condenser with the humidity. That keeps the condenser very cool, almost ambient temperature, even when on high.

The downside is that some of the inside air is exposed to the water and makes for a higher humidity. The upside is that it's real cheap to run.

As for sizing, I have a 10k for about 700 sq. feet. About 1200 if you count the basement, which has an open stairwell from the kitchen. So I am pretty sure I am not over sized.

 

[kwired]

I think it's the new design, which uses the water from the humidity in the house to cool the condenser. Instead of just draining out, it pools up about a half inch and allows the fan to mist the condenser with the humidity. That keeps the condenser very cool, almost ambient temperature, even when on high.

The downside is that some of the inside air is exposed to the water and makes for a higher humidity. The upside is that it's real cheap to run.

As for sizing, I have a 10k for about 700 sq. feet. About 1200 if you count the basement, which has an open stairwell from the kitchen. So I am pretty sure I am not over sized.

You really think it is adding humidity? That water should be fairly chilled and needs some heat to assist in evaporation. Not saying a little doesn't find its way back into the air but is probably not significant enough to notice. If anything the air being so cold means less run time before the thermostat cycles it off. This is what is nice about two stage units, but you are not very likely to find that in a portable unit. They run most of the time on low stage which consumes less energy, but is still cooling and dehumidifying, where a single stage unit reaches set point quicker and shuts off.

 

[K8MHZ]

You really think it is adding humidity? That water should be fairly chilled and needs some heat to assist in evaporation. Not saying a little doesn't find its way back into the air but is probably not significant enough to notice. If anything the air being so cold means less run time before the thermostat cycles it off. This is what is nice about two stage units, but you are not very likely to find that in a portable unit. They run most of the time on low stage which consumes less energy, but is still cooling and dehumidifying, where a single stage unit reaches set point quicker and shuts off.

OK, maybe I didn't word that properly. It's not adding humidity, it's just not removing as much as the old one did. I live in an area that gets very humid in the summer.

I have a fairly accurate hygrometer so I can actually measure the difference. The old one would bring the humidity from 80 percent to 55, but it worked harder to cool the air and was harder on the electric bill. While running, a steady stream of water would pour out the unit. The new one won't pull 80 percent down to less than 65 percent, but cools way faster and is way cheaper to run. Also, no water pours from the new unit as it is used to cool the condenser.

Much more air passes through the new one, too. Even with the fan on low, it blows more air than the old one did on high. That's why it's so loud, the fan is high volume and you can tell that by the noise.

We don't use much AC here. Decades ago it was much cooler in the summer so AC was pretty rare. Now our cooling period is about mid June to end of September with July and August being the only two months where you would use it every day. So AC issues aren't life or death matters, but one would think that a 'better' design would also remove humidity better as well as removing heat better. Especially if it's considerably louder.

 

[kwired]

OK, maybe I didn't word that properly. It's not adding humidity, it's just not removing as much as the old one did. I live in an area that gets very humid in the summer.

I have a fairly accurate hygrometer so I can actually measure the difference. The old one would bring the humidity from 80 percent to 55, but it worked harder to cool the air and was harder on the electric bill. While running, a steady stream of water would pour out the unit. The new one won't pull 80 percent down to less than 65 percent, but cools way faster and is way cheaper to run. Also, no water pours from the new unit as it is used to cool the condenser.

Much more air passes through the new one, too. Even with the fan on low, it blows more air than the old one did on high. That's why it's so loud, the fan is high volume and you can tell that by the noise.

We don't use much AC here. Decades ago it was much cooler in the summer so AC was pretty rare. Now our cooling period is about mid June to end of September with July and August being the only two months where you would use it every day. So AC issues aren't life or death matters, but one would think that a 'better' design would also remove humidity better as well as removing heat better. Especially if it's considerably louder.

Sounds too efficient to me. By that I mean it cools the air too quickly, before much humidity has been removed. A smaller unit may actually provide more comfortable conditions.

 

[K8MHZ]

Sounds too efficient to me. By that I mean it cools the air too quickly, before much humidity has been removed. A smaller unit may actually provide more comfortable conditions.

Perhaps.

I went by the square footage in the specs. I am cooling a couple hundred more square feet than the specs call for.

 

[LEO2854]

What is the maximum fuse or breaker size allowed on the nameplate?
You may be allowed to run it on a 20 amp breaker.
What is minimum circuit ampacity according to nameplate?

I don't think you can do that.

240.4(D) Small Conductors. Unless specifically permitted in 240.4(E) or (G), the overcurrent protection shall not exceed that required by (D)(1) through (D)(7) after any correction factors for ambient temperature and number of conductors have been applied.

240.4 (D)(3) 14 AWG Copper. 15 amperes