A/C Went Out

[easysurfer]

My A/C went out yesterday.

Boy was it brutal trying to get a restful night of sleep. The temp got as high as 100 degrees during the day. I did my best with a ceilng fan and two portable fans blowing at me.

But got the A/C fixed this morning so I'm a happy camper. The problem was a capcitor (which controlled the compresso) that blew out and needed replacing.

 

[REWahoo]

The problem was a capcitor (which controlled the compresso) that blew out and needed replacing.

You are very fortunate as that's one of the least expensive components to replace.

 

[aaronc879]

I almost cracked and turned my A/C for the first time ever but I didn't. It got up to 96 for a high and only down to 76 with very high humidity for a low. People lived for centuries without a/c so it's not a neccesity, it's a luxury. Being unemployed for almost a year, I need to cut out luxuries. Hopefully I sell the condo before heating season because I won't be able to go without heat when it's below freezing. That's much worse than going without a/c when it's 100 degrees.

Glad to hear you got it fixed so soon. I've known people who had to wait almost a week.

 

[easysurfer]

You are very fortunate as that's one of the least expensive components to replace.

I was ready to just give the guy a blank check as I got sick of sweating it out last night.

 

[easysurfer]

I almost cracked and turned my A/C for the first time ever but I didn't. It got up to 96 for a high and only down to 76 with very high humidity for a low. People lived for centuries without a/c so it's not a neccesity, it's a luxury. Being unemployed for almost a year, I need to cut out luxuries. Hopefully I sell the condo before heating season because I won't be able to go without heat when it's below freezing. That's much worse than going without a/c when it's 100 degrees.

Glad to hear you got it fixed so soon. I've known people who had to wait almost a week.

The A/C repair place does a lot of work in my condo. They were quick and even gave 10% off.

It was just horrible last night. I had a ceiling fan, and two portable fans blowing right at me. Still I had to get up a few times just to drink some ice water to try and keep cool.

 

[ziggy29]

But got the A/C fixed this morning so I'm a happy camper. The problem was a capcitor (which controlled the compresso) that blew out and needed replacing.

Ah, that's a component that helps protect the (expensive) compressor from getting fried by power flickers, surges and spikes. It's essentially the A/C equivalent of a surge protector "taking one for the team" and dying to protect the components plugged into it. It always sucks when A/C goes out this time of year, but at least the cheap part "did its job".

 

[FIREd]

Glad your A/C is repaired!

When we lived in Alabama, our A/C broke down in the middle of July one year. It took a month to get the replacement part! After a week without A/C, I broke down and bought a window unit to keep at least one room in the house cool.

 

[ziggy29]

Glad your A/C is repaired!

When we lived in Alabama, our A/C broke down in the middle of July one year. It took a month to get the replacement part! After a week without A/C, I broke down and bought a window unit to keep at least one room in the house cool.

We've thought about getting one of those portable units that can be moved from room to room... just in case our A/C craps out in midsummer and it takes many days to fix.

 

[easysurfer]

Glad your A/C is repaired!

When we lived in Alabama, our A/C broke down in the middle of July one year. It took a month to get the replacement part! After a week without A/C, I broke down and bought a window unit to keep at least one room in the house cool.

All I got is balcony windows. No doubt if I could have installed a window unit, I would have yesterday .

I did learn a couple of things though. One was the 20 degree rule of thumb. That is that many A/Cs are only designed to cool up to about 20 degree cooler than the outside temp. For example, if it's 100 outside and you set the thermostat to 65 instead of 80, the A/C will keep on running and you are not only wasting money but asking for A/C trouble. Two, sweating at night with no A/C, a bottle of ice water, wrapped in a t-shirt works great on the back of the neck.

 

[Texas Proud]

All I got is balcony windows. No doubt if I could have installed a window unit, I would have yesterday .

I did learn a couple of things though. One was the 20 degree rule of thumb. That is that many A/Cs are only designed to cool up to about 20 degree cooler than the outside temp. For example, if it's 100 outside and you set the thermostat to 65 instead of 80, the A/C will keep on running and your not only wasting money asking for A/C trouble. Two, sweating at night with no A/C, a bottle of ice water, wrapped in a t-shirt works great on the back of the neck.

I do not know where you got the 20 degree rule.... our AC can get our house into the low 70s when it is 100+ degrees outside... I have not tried to go lower, but the AC is not running all the time, it is cycling...

 

[Rustward]

I do not know where you got the 20 degree rule.... our AC can get our house into the low 70s when it is 100+ degrees outside... I have not tried to go lower, but the AC is not running all the time, it is cycling...

I think the 20 degree difference is between the AC inlet temperature and the outlet temperature.

Not an AC guy here, but this might help:
If you start with the interior space at 100, the air coming out of the AC will be (within some range) about 80, and the interior space will slowly cool below 100.
Say the interior gets to 95, then the AC cools that air to 75, and the interior space slowly cools to below 95.
Assuming the AC is set to maximum cooling, this continues until the heat entering the space is equal to the rate at which the AC can remove heat.

I'm sure others can offer a much better explanation.

 

[easysurfer]

I think the 20 degree difference is between the AC inlet temperature and the outlet temperature.

Not an AC guy here, but this might help:
If you start with the interior space at 100, the air coming out of the AC will be (within some range) about 80, and the interior space will slowly cool below 100.
Say the interior gets to 95, then the AC cools that air to 75, and the interior space slowly cools to below 95.
Assuming the AC is set to maximum cooling, this continues until the heat entering the space is equal to the rate at which the AC can remove heat.

I'm sure others can offer a much better explanation.

Thanks for the explanation.

Here's an article about the rule:

Go easy on your air conditioner | The Columbus Dispatch

 

[Dimsumkid]

Glad to hear you got your AC fixed! I just replaced mine in the last 3 weeks due to a leak. The refrigerant R-22 is being phased out to R-134a (Puron), so my repair would've cost $400-500 on a 16-17 yr old system. Decided to get quotes and replaced it w/a new 4 ton unit for $2875 instead. I didn't see the point of dropping $500 on a system that would last 5 yrs tops and no guarantee the leak wouldn't happen again this summer since they couldn't easily find it. Apparently, you're allowed only 1 R-22 recharge under law.

Another thing people never seem to mention, AC units have 2 systems - cooling and dehumidifying. We had to go thru 3 straight days of 95+ temps and 90+% humidity. We closed all the blinds/curtains, ran 2 dehumidifiers and 2 high velocity circulating fans all 3 days. Internal temps were: 1st day 78-80, 2nd 80-82 and 3rd 82-85. With the humidity kept low, it wasn't uncomfortable inside until it got over 83+.

 

[Texas Proud]

Thanks for the explanation.

Here's an article about the rule:

Go easy on your air conditioner | The Columbus Dispatch

The article just does not make sense.... I have heard there is a limit with heat pumps, but not with AC units...

There is no facts behind this article.... and it just does not follow my actual house (nor my BS meter)....

IOW, let's say we have a REALLY insulated house... where the heat of the day does not get into it that much.... you turn on the air... it will cool it down... since there is not much heat being put into the system, why is there a 20 degree limit

Also, how do they get server rooms down to 65 degrees (I forgot about our server room when posting before, we keep it at 65 with outside temps over 100)...

I think this is an old wife's tale....



Edit to add.... it seems that the 20 degrees is just the sizing of the AC unit... IOW, putting in a bigger unit (like we have down here) is not efficient in cooler climates...

IOW, you can get better cooling, but you have to pay a price for it...


http://www.askthebuilder.com/central-air-conditioning/

 

[Rustward]

The article just does not make sense.... I have heard there is a limit with heat pumps, but not with AC units...

There is no facts behind this article.... and it just does not follow my actual house (nor my BS meter)....

IOW, let's say we have a REALLY insulated house... where the heat of the day does not get into it that much.... you turn on the air... it will cool it down... since there is not much heat being put into the system, why is there a 20 degree limit

Also, how do they get server rooms down to 65 degrees (I forgot about our server room when posting before, we keep it at 65 with outside temps over 100)...

I think this is an old wife's tale....

The article is a little iffy.

The article might be a little specific to the latitude of Columbus Ohio, which does not see the heat we see here, and to consumer home air conditioning, not server rooms. The home AC systems in OH are probably sized with less capacity than those in Texas. I was told that central systems in this area are sized so that they run just about all the time when it is 110 outside (I believe that 110 is correct, but don't put money on it). Thankfully we usually don't see 110 for more than a few hours per year.

 

[Texas Proud]

The article is a little iffy.

The article might be a little specific to the latitude of Columbus Ohio, which does not see the heat we see here, and to consumer home air conditioning, not server rooms. The home AC systems in OH are probably sized with less capacity than those in Texas. I was told that central systems in this area are sized so that they run just about all the time when it is 110 outside (I believe that 110 is correct, but don't put money on it). Thankfully we usually don't see 110 for more than a few hours per year.

I agree... after reading a bit more, it seems like it is how they size them in different locations...

In my house, the AC unit can actually cool the house down from 82 to 75 when it is 105 outside... I know because I have a setup/setback thermostat and have it set at 82 during the day and 75 or 76 for when I get home...

I do have the problem of the upstairs being hotter than down... but when the AC unit craps out I am going to see about getting two systems...

 

[easysurfer]

Here we go, another article referring to the 20-degree rule.

Hot Weather | What the heck happened to the A/C?! | KXAN.com

The article says, "The fact is, most home air conditioners are not sized to cope with triple-digit temperatures." So it seems, the 20-degree rule is a rule of thumb for most A/Cs. I guess as we say, YMMV. Maybe you have one that can handle the load. Or you might have one that konks out before the 20 degree rule.

 

[Dimsumkid]

I do have the problem of the upstairs being hotter than down... but when the AC unit craps out I am going to see about getting two systems...

I would check you insulation level in the attic. I added R-30 to the existing R-12 and it helped reduce the 1st/2nd floor temp variations. Also, check if your system has a variable speed AC/DC motor. I was told by every estimator to run the fan 24/7 which would cost me very little in energy use and it would reduce the temp variations too. With both of these changes, there's a 4-6 degree difference compared to 5-9 degrees last year.

I did have 2 separate HVAC systems in my old house, but you'll need to pay for additional duct and install costs for 2 separate systems/maintenance. The advantage will be precise control of temps for each floor/area and overall lower utility costs.

 

[meierlde]

The article just does not make sense.... I have heard there is a limit with heat pumps, but not with AC units...
I think this is an old wife's tale....

Its not true in the reverse sense for heat pumps either they provide a reasonable gain to the low 30s outside (no need for aux heat). Once you get to the lower 20s then the aux electric heat is needed. So a typical heat pump will run with reasonable efficiency with a 40 degree F temp difference in heating mode. Of course any refrigeration cycle works best (most heat moved per unit of electricity) when the inside outside delta is small. When you get to 40 degree delta temps in cooling the same issue applies that the cooling per unit of electricity goes down, i.e. the compressor has to run longer per unit of cooling. As an example on the Lennox units I have (I have the detailed performance specs from their web site) the unit produces in one configuration 30k btu/hr at 85 and 23.8k btu/hr at 115 (for a constant wet bulb temp). For heating to show the other side of the curve at 65 it is 34.6kbtu/hr at 45 26.6 at 25 18.2 at 5 12.7 and at -15 6.5.

 

[ziggy29]

Its not true in the reverse sense for heat pumps either they provide a reasonable gain to the low 30s outside (no need for aux heat). Once you get to the lower 20s then the aux electric heat is needed. So a typical heat pump will run with reasonable efficiency with a 40 degree F temp difference in heating mode.

Sounds about right.We have a heat pump and usually the temperatures have to persist below about 25º for several hours here before the aux heat kicks in (and I can feel my wallet getting lighter whenever it does). We get down to the mid to upper 20s fairly frequently in a typical winter (but not this winter; we didn't have winter this year) but not all that commonly in the low 20s or below. So last winter the aux never kicked on a single time. Usually I only hear it come on 3-4 mornings a year, and usually only for a few minutes at a time.

 

[Texas Proud]

I would check you insulation level in the attic. I added R-30 to the existing R-12 and it helped reduce the 1st/2nd floor temp variations. Also, check if your system has a variable speed AC/DC motor. I was told by every estimator to run the fan 24/7 which would cost me very little in energy use and it would reduce the temp variations too. With both of these changes, there's a 4-6 degree difference compared to 5-9 degrees last year.

I did have 2 separate HVAC systems in my old house, but you'll need to pay for additional duct and install costs for 2 separate systems/maintenance. The advantage will be precise control of temps for each floor/area and overall lower utility costs.

We have lots of insulation.... my difference is about 4 or so degrees, but that is noticable when you have the downstairs at a higher level to save money...

 

[timeasterday]

Ah, that's a component that helps protect the (expensive) compressor from getting fried by power flickers, surges and spikes. It's essentially the A/C equivalent of a surge protector "taking one for the team" and dying to protect the components plugged into it. It always sucks when A/C goes out this time of year, but at least the cheap part "did its job".

It's actually used to help create more of a rotating magnetic field by delaying one of the motor windings. Otherwise you can't turn a motor with single-phase AC power.

 

[Dimsumkid]

We have lots of insulation.... my difference is about 4 or so degrees, but that is noticable when you have the downstairs at a higher level to save money...

The comfort of a split system will spoil you, I miss having it in our current house. It's best to do it when you need to replace your current setup unless cost isn't an issue. I went from hot water heat/cold water cooling all water pipes to gas/AC using duct.

 

[LakeTravis]

Just to clarify a few points:

1. As someone pointed out, it's a "start capacitor" which enables the compressor to get going. It has limited use as a surge protector. When the capacitor goes out, the compressor can't start. Most systems have the fan motor wired into the same capacitor for the same reason, so when the capacitor goes out the fan isn't running either. All you hear from the outdoor unit is a faint hum.

2. Many recommend a "boost" capacitor, which helps to lower the initial electrical current required to start the compressor.

3. The longer an AC unit runs, the more efficient it becomes. It is removing humidity from the interior air, and dry air is easier to cool than wet air. It also reduces the heavy electrical draw required to start the compressor each time. If you've got a system that can cool your home down to 78 when it's 105 outside and then cycles every hour or so, it's most likely oversized for your home.

4. Zoning one unit can provide the same efficiencies as two units at much lower costs - both initial and ongoing. Besides, seldom are any of us in all rooms of our homes at all times. Why heat/cool the entire space if we aren't using all of it?

5. The other old "rule of thumb" of 1 ton of AC for every 500sf of space has been replaced with much more exact science. For instance, I have a 3400sf two story in central Texas that has a single 5 ton unit. And when it's 110 degrees outside, it's 78 degrees on the inside with only a 2 degree differential between first and second story. Most would have thought this house would have required 2 systems. But a Manual J calculation of the heat load of the house works out to 5 tons with a bit of capacity left. And in practice, it's proven to be very efficient. This month, our electric bill was less than $190 and that's with the AC set to cool down to 70 from 6am-8am, up to 82 until 5p, down to 78 until 10p, and 74 from 10p-6a.

 

[Texas Proud]

Just to clarify a few points:

1. As someone pointed out, it's a "start capacitor" which enables the compressor to get going. It has limited use as a surge protector. When the capacitor goes out, the compressor can't start. Most systems have the fan motor wired into the same capacitor for the same reason, so when the capacitor goes out the fan isn't running either. All you hear from the outdoor unit is a faint hum.

2. Many recommend a "boost" capacitor, which helps to lower the initial electrical current required to start the compressor.

3. The longer an AC unit runs, the more efficient it becomes. It is removing humidity from the interior air, and dry air is easier to cool than wet air. It also reduces the heavy electrical draw required to start the compressor each time. If you've got a system that can cool your home down to 78 when it's 105 outside and then cycles every hour or so, it's most likely oversized for your home.

4. Zoning one unit can provide the same efficiencies as two units at much lower costs - both initial and ongoing. Besides, seldom are any of us in all rooms of our homes at all times. Why heat/cool the entire space if we aren't using all of it?

5. The other old "rule of thumb" of 1 ton of AC for every 500sf of space has been replaced with much more exact science. For instance, I have a 3400sf two story in central Texas that has a single 5 ton unit. And when it's 110 degrees outside, it's 78 degrees on the inside with only a 2 degree differential between first and second story. Most would have thought this house would have required 2 systems. But a Manual J calculation of the heat load of the house works out to 5 tons with a bit of capacity left. And in practice, it's proven to be very efficient. This month, our electric bill was less than $190 and that's with the AC set to cool down to 70 from 6am-8am, up to 82 until 5p, down to 78 until 10p, and 74 from 10p-6a.

What do you mean by zoning one unit

How do you get the rest of the house cool when you need it? PS... we need it most of the time because my kids are in their rooms upstairs... my wife is in her studio upstairs, I am downstairs watching TV or in the bedroom...