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Discussion Starter · #1 ·
In the old days. Condensers wee rated at either 125, or 130°F condensing temp.

Now, most are rated at 105°F condensing temp.

Does anyone know why.
 

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Not sure what you mean by rated for condensing temp. If it gets to 100 deg F in Texas they allow the unit to get to 130 deg F by design/max temp? I would imagine that the newer units having larger condensor coils try keep the head pressure down which results in lower power consumption, higher SEER? I was taught that you added 20-30 deg above ambiant temp to get head pressure/temp before you started worrying about high head pressure. The newer units seems to run about 20 quite comfortably.
 

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Discussion Starter · #3 · (Edited)
ARI, now AHRI, rating conditions for air to air, are 95°F outdoor temp.

Capacity at that outdoor temp was for 130°F condensing temp at one time.
Then lowered to 125.
And now 105.

The 25 to 30 about outdoor temp was the condensing temp.
95+30=125.

look at the compressors in new high efficiency equipment.
You see it has a compressor in it that is probably rated at 41,000BTUs at 130° condensing temp.
And 49,000BTUs at 105° condensing temp.
 

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probably because today to achieve those numbers the unit's would be bigger than the house:laughing:,although most manufacturers have adjusted since the efficency change rather quickly and have now got somewhat reasonable physical dimensions of the equipment..............i thought it had something to do with the smaller compressors they are using per size of equipment,compression ratio or something?.....maybe because the smaller compressors pull less amps,thereby letting manufacturer meet energy efficency standards.....not real sure and i'm interested myself been.
 

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Discussion Starter · #5 ·
Yep. At lower condensing temp, the compressors amp draw is lower. And it makes it easier for them to reach 13 SEER min rating, without having to make the coil another 30 to 50% bigger then what they are.

Using a slightly larger condenser, with a smaller compressor is the lesser of 2 evils.

Add in a larger evap coil, And you get a lower compression ratio.
Keeping the amp draw a little lower yet.

If they used its 130° condensing rating. Then either the coils would have to be that much larger yet. Or they would need to make a major improvement to compressor technology. To meet 13 SEER min.
 

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Larger condensing coils spread the overall heat of extraction over a larger area making any given point of testing a lower temperature. If you were to put a box over a new 24K capacity unit and a box over a twenty year old 24K capacity unit, both boxes would wind up being the same temperature inside.
 

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Discussion Starter · #7 ·
Wouldn't the new units box be bigger. There for it would have a large surface area to dissipate heat. making it cooler. LOL
 

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Aw, just turn the lawn sprinkler on it then you have an evap condensor and a watered lawn with the remainder.:thumbsup:
 

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Discussion Starter · #9 ·
Aw, just turn the lawn sprinkler on it then you have an evap condensor and a watered lawn with the remainder.:thumbsup:
And lots of crude and scale to clean off next year.
 

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Discussion Starter · #16 ·
This helps out two fold. You have a unit in need of repair and the leaking refrigerant destroys the ozone layer so it will get hotter.
Judging by our current summer so far, we must have done too good of a job saving the ozone layer.
 

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Judging by our current summer so far, we must have done too good of a job saving the ozone layer.
Tis true, but the high humidity with the low ambient temps are slugging compressors pretty well. Hopefully, more that are out of warranty will be dying then those that are still under warranty.

Contractors can make out on warranty parts, distributors only lose money on warranty parts.
 

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Discussion Starter · #18 ·
Yea, I can make money on labor when a warranty part goes out.

Just hear more squawking about why it broke.
 

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condensers temp

In the old days. Condensers wee rated at either 125, or 130°F condensing temp.

Now, most are rated at 105°F condensing temp.

Does anyone know why.
Maybe because today's refrigerants boiling temp are higher than those used before, plus all this new devices been install today's days.
 

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Discussion Starter · #20 ·
R22 is the same today as it was 50 years ago.

Since its the saturation temp were talking about.
It doesn't make a difference weather its R22, or R410A.
 
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