Need AC operation explained ! ! !

My wife insists on setting the whole house AC thermostat at 70-72 at night. I've told her that if the outside temperature is 67, the AC won't work correctly. That the outside temperature has to be higher than the temperature you're trying to cool the house to. Can someone state this in an explanation that she will understand?

Also, during the night the circuit breaker that the AC is on has been tripping lately. Could this be because the unit is running for hours without shutting down? Putting a load on it and thus causing the circuit breaker to to trip?

Reply to
TOM KAN PA
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She understands everything she needs to, she knows you and knows you are crazy. :-)

Many times the outside temperature is less than the set temperature. One of two things happen. If the inside temperture is less than the set temperture, nothing happens since the thermostate will be happy. If the inside temperature is higher than the set temperature then the AC will start running and dump the excess heat outside. Since it is pumping the heat downhill, it will work less hard and save you money.

If anything running at night when it is cool would be less load on the AC (there are unusual circumstances that this may not be true, but it does not sound like it here). There are a number of possible problems that could cause the breaker to trip, but it sounds more likely that the breaker is going bad and needs to be replaced. Do you run the AC during the day? Does the breaker trip then?

Reply to
Joseph Meehan

When the outside temperature gets below 70 the more indoor heat load you get on the evaporator coil the better. This is because when the system heatload becomes too low the pressures drop below freezing on the evaporator coil which results in coil blockage. Which results in possible liquid flooding back to the compressor which can ruin it in no time flat. In lower temperature environments a control is needed to control the condenser blower motor so the condensing temperatures stays within tolerable specifications. The colder it gets in the conditioned space the more dangerous it is for the compressor. They used to have suction line accumulators and low pressure switches to help protect the compressor, which many units don't have these days. These days accumulators are rare on A/C units, --but they are critical for protecting Heat Pumps and therefore are installed on them. Where nights get cold strap on crankcase heaters are essential to keep refrigerant from condensing into the compressor's oil which leads to slugging and oil where it shouldn't be in the sealed system. Along with premature compressor failures.

Reply to
D-

She seems to understand . Your house warms up, and gets humid, at night she wants it kept comfortable. Besides cooling the house you are keeping the humidity under control ,which usually rises outside at night. Im not sure of the actual low temp it is damaging to run your ac, but I beleive for some units it is 55 or lower, you wont hurt your ac running it at 65 outside. And it will work fine. If Its hot and humid in the house run your AC . Your breaker problem is different, have a Pro check it out , it could be something serious is happening and should be repaired before more damage occurs

Reply to
mark Ransley

Sure. I'll explain it to her.

First, however, you explain to me how the outside temperature has anything to do with the air conditioner.

The air conditioner is controlled by the thermostat. The thermostat measures the inside temperature.

It does not matter of the outside temperature is 100 degrees or zero degrees. If the inside temperature is higher than what the thermostat is set for, the air conditioner turns on. The thermostat has no contact with the outside temperature. It cannot know what the outside temperature is. What's more, it doesn't care. It is only concerned with the inside temperature. That's its job. It's very single-minded about it, very focused. It has no imagination.

Perhaps your air conditioner has something on it that measures the outside temperature for some reason. This is not impossible. I have just never seen one nor could I fantom why it would. If it does, I want to go out and find one just like yours so that I can learn something new. Look in the manual that came with the air conditioner. I'm sure it would tell you all about how the air conditioner can sense the outside temperature. Quote me what it says.

Thank you.

Good luck.

Peter

Reply to
peter

I stand corrected.

Then why does a refrigerator in a garage quit working when the garage gets cold?

Reply to
TOM KAN PA

Alot of portable home dehumidifiers start to freeze up below 60f its their design. Regular home refrigerators have a low temp operating range also. They are designed for use in a heated area .

Reply to
mark Ransley

shut up retardo boi..

Reply to
Jack Lime

Same principle exactly, just at a different thermostat set point (typically

72-75 degrees for air conditioning a house, 38-40 degrees inside a refrigerator). Your air conditioner won't run when it's 40 degrees outside, either.

To put it a bit differently: if the garage is at 32 degrees, you don't even

*need* a refrigerator to keep your food cold, do you? You could unplug the fridge, and prop the door open.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

Reply to
Doug Miller

That's an explanation she's sure to understand! :-)

Reply to
PhotoMan

Not bad..

Wrong.

Why? So far, you are wrong.

60F...run the AC...its not going to hurt a thing..and its actually cheaper to run the lower the outdoor temps..

No.

You need to get a competent tech out to check it for you before you inversly trip the flux capacitor out of phase with the synchrometer..

Really...seriously...get it checked..

Reply to
CBHvac

== Did ya tell her? She's gotta love that :-) == ==

Reply to
gini52

If it is 67 outside, absent AC, it will be above 67 inside, since you have heat loads indoors. And depending on your locale, you also need to lower humidity, the 67 outdoors may be very humid and uncomfortable.

Just set it where you're comfortable. If she is most comfortable at 70-72, then fine.

There's no arguing with taste, or in this case, psychrometrics.

Reply to
Richard J Kinch

Get a programmable thermostat. Set it to 70-72 when you guys go to sleep...kick it up to 78 or so about an hour later.

As you've already read, you're incorrect.

Could be a lot of reasons. Get a tech to check it out.

Have a nice week...

Trent

Dyslexics of the world ... UNTIE !

Reply to
Trent©

Again...the cooling device...in this case, the refrigerator...doesn't care about the outside environment. It measures the INSIDE temperature...and cycles when the INSIDE temperature fluctuates.

But there is always infiltration. No refrigerator can be 100% insulated. So, if the outside temperature is very cold, the cold air will infiltrate (actually, in the other direction...depending on the temperature) into the refrigerator...which helps to cool the inside air and contents.

Have a nice week...

Trent

Dyslexics of the world ... UNTIE !

Reply to
Trent©

You're a facinating person. What do you do for a living?

Peter

Reply to
peter

What does it matter? Do you think the average person has any concept of the fundamental laws of thermodynamics and conservation of energy? Leave the guy alone. Anyone can make anyone else look stupid on the right subject.

All I know is that I know nothing.

Reply to
Bruce

Bravo Bruce...i bet he's well versed in everything!

Reply to
Dano

Except spelling, obviously! lol

Have a nice week...

Trent

Cat...the OTHER white meat!

Reply to
Trent©

A fridge runs until the temp in the refrig section gets to 40 (or whatever you've set it for). So, if the garage is 40, then the refrig stays at 40. Now, as it happens, without the compressor running, the freezer section warms up to 40 after a while, but that's not the refrigerator's fault!

Reply to
Stormin Mormon

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