Thread: AC Units Consuming More and More (did some due diligence)

1. Originally Posted by dan sw fl
OR if he doesn't like to be at the mercer of his utility company ...
Raise it to 78'F / 25.6'C .:. reduce electric cost\$ > _ 40%_
That's true, Dan. But I was attempting to "warm him up" to accepting a higher setpoint at a not so drastic jump.

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Originally Posted by Shophound
That's true, Dan. But I was attempting to "warm him up" to accepting a higher setpoint at a not so drastic jump.
78'F ought to Feel ABSOLUTELY TERRIFIC when it's 120'F outside. ..!...!!....!!!

3. Originally Posted by dan sw fl
1.732 ___ 1.732 .. SQRT 3 for 3-phase power
12 ___ ___ 12 Amps
208 ______ 220 V Nice try, did you think I would miss you changing the voltage from 240v down to 220v?
4323.1 ___ 4572.48 Volt-Amps

Voltages & Power Factor are not known with certainty.
There is nothing that even needs to be calculated.
The Measured power is stated as 4,400 Watts.

So , if OP wishes one to evaluate the performance as stated in post #1 ( copied below)
the air flow rate, supply air temperature, model numbers of the condenser and air handlers must also be provided.
Room temperature and outdoor temperature are provided.
Relative humidity inside would help, but one can assume it's ~40'F for discussion purposes.

Unit #1:

3-Phase, RLA 7.0, Min. Supply Circuit Ampacity 10
With AC running at 22*C with outdoor temp at 30*C the amp readings were 11-12 amps per phase
and 12 amps all together including fan

Wattage measurement with unit set at 20*C with outdoor temp at 30*C (night) = 4400 watts

Unit #2:

1-Phase, RLA 13.7, MSCA 19 amps
With AC running at 22*C with outdoor temp at 30*C the amp reading was
14 amps and 18 including fan
Wattage measurement with unit set at 20*C with outdoor temp at 30*C (night) = 3000 watts
I find it interesting that the power factors are so much different between units. Another oddity is the fact there is 3 phase service to a residential apartment unit, I have never seen 3 phase in house (not including mansions), much less an apartment. I'd be interested to see the watts test/meters/conditions. 3 phase wattmeters aren't exactly common.

The calculator you linked to is right, and once it proved you are wrong you had to go an fudge the line to neutral voltage from 120v to 110v to try and prove a point. Only after you actually used the calculator and it proved you wrong to you try to discredit the calculator. I even mentioned there are other factors in my previous post BEFORE you posted.

I wouldn't even care so much if your didn't come with with the flamethrower blazing, laughing at my calculations w/o providing any proof of yours. Highly unprofessional in the AOP forum. At our shop we have a policy never to correct another tech in front of a customer. We talk about it later if there is a disagreement.
Last edited by 54regcab; 11-02-2012 at 10:18 PM.

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Originally Posted by 54regcab
I find it interesting that the power factors are so much different between units. Another oddity is the fact there is 3 phase service to a residential apartment unit, I have never seen 3 phase in house (not including mansions), much less an apartment. I'd be interested to see the watts test/meters/conditions. 3 phase wattmeters aren't exactly common.

The calculator you linked to is right, and once it proved you are wrong you had to go an fudge the line to neutral voltage from 120v to 110v to try and prove a point. Only after you actually used the calculator and it proved you wrong to you try to discredit the calculator. I even mentioned there are other factors in my previous post BEFORE you posted.

I wouldn't even care so much if your didn't come with with the flamethrower blazing, laughing at my calculations w/o providing any proof of yours. Highly unprofessional in the AOP forum. At our shop we have a policy never to correct another tech in front of a customer. We talk about it later if there is a disagreement.
It's been an interesting thread observing this discussion that you are having with yourself on the methods and necessity of a calculation.

The real point is that the OP has not provided nearly enough information on the electric usage, building envelope, maximum environmental condition and unit model numbers to make an independent determination and overall validation of what one might expect in operating cost\$.

More than 7,000 total watts for 1,200 square foot residence is not what one would normally ( or ever?) see in the U.S.
The OP wishing for 68'F in the desert can not be achieved in an economical manner based on normal U.S. electric rates..

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