Yo Jeanius

Posted by The King on February 20, 2009, 9:12 pm

Lets plug your numbers into this and tell me what you get.

CFM = volts x amps x 3.412 / 1.08 x temperature rise

= 237 x 20 x3.412 / 1.08x 19

=16177 / 20.5

788 CFM

You need 400 CFM per ton so Id say your as good as it gets air flow
wise. 12 CFM isn't going to mean jack shit in over all performance.
You are more than welcome to look it up on a fan performance curve.

Air flow isn't causing your HP to be noisey while switching into and
being in defrost.

Moving along..

3.412 BTUH = 1 watt.

To find BTUH using the temp rise across a electric heat element
the formula is the Sensible Heat Equation.

BTUH = E x I x 3.412

Now that you know the BTUH you can find CFM by using the formula at
top

To find BTUH in heat mode;

BTUH = CFM x TD (db) x 1.08

To find BTUH in cooling mode;

BTUH = CFM x HD x 4.5

HD = total heat difference ie. Enthalpy DT measured in wet bulb
across the HX. You'll need a total heat chart to get those numbers
unless you post accurate wet bulb numbers in cooling I cant help.

4.5 is a constant, once again at sea level which changes with
altitude. A mute point in your case.

Now throw those shit equations in the trash and get to work.

Otherwise I will enjoy my morning bowl of Coco Puffs for breckfy and
thank God you helped to make it possible. :)

Hope this helps.

Posted by Jean on February 20, 2009, 10:07 pm

On Fri, 20 Feb 2009 21:12:20 -0500, The King

>Lets plug your numbers into this and tell me what you get.
>CFM = volts x amps x 3.412 / 1.08 x temperature rise
>= 237 x 20 x3.412 / 1.08x 19
>=16177 / 20.5
>788 CFM

Is your formula ordered as follows?

A) 237 x 20 x 3.412 / 19 x 1.08 = 919
which is the same as 237 x 20 x 3.412 x 1.08 / 19 = 919

or is it

B) 237 x 20 x 3.412 / (19 x 1.08) = 788

Remember your math rules from school?

Rule 1: First perform any calculations inside parentheses.
Rule 2: Next perform all multiplications and divisions, working from
left to right.
Rule 3: Lastly, perform all additions and subtractions, working from
left to right.

If your formula is right, then Goodman's printed installation &
operating sheets are good for shit. (Their heating performance data
sheet for my product is crap. It shows R22 data but labelled for R410.
My HVAC guy says to throw them out. They are worthless.)

>You need 400 CFM per ton so Id say your as good as it gets air flow
>wise. 12 CFM isn't going to mean jack shit in over all performance.
>You are more than welcome to look it up on a fan performance curve.

I know. I've had to "prove" my airflow. People keep pointing at other
reasons for their problems. I have no choice. Goodman insists on
knowing actual airflow. They have been picky about charge TO THE
OUNCE.

>Air flow isn't causing your HP to be noisey while switching into and
>being in defrost.
>Moving along..
>3.412 BTUH = 1 watt.
>To find BTUH using the temp rise across a electric heat element
>the formula is the Sensible Heat Equation.
>BTUH = E x I x 3.412
>Now that you know the BTUH you can find CFM by using the formula at
>top
>To find BTUH in heat mode;
>BTUH = CFM x TD (db) x 1.08

CFM = BTUH / (TD x 1.08)

If this is correct, then Goodman's formula is shit. See my post in the
other thread. I've given URL's to their data sheets.

Do you have a URL for your formula?

>To find BTUH in cooling mode;
>BTUH = CFM x HD x 4.5
>HD = total heat difference ie. Enthalpy DT measured in wet bulb
>across the HX. You'll need a total heat chart to get those numbers
>unless you post accurate wet bulb numbers in cooling I cant help.
>4.5 is a constant, once again at sea level which changes with
>altitude. A mute point in your case.
>Now throw those shit equations in the trash and get to work.
>Otherwise I will enjoy my morning bowl of Coco Puffs for breckfy and
>thank God you helped to make it possible. :)

You REALLY don't want to know what actually goes into making Coco
Puffs ;)

>Hope this helps.

Yep.

Posted by The King on February 20, 2009, 10:40 pm

>On Fri, 20 Feb 2009 21:12:20 -0500, The King

>>Lets plug your numbers into this and tell me what you get.
>>CFM = volts x amps x 3.412 / 1.08 x temperature rise
>>= 237 x 20 x3.412 / 1.08x 19
>>=16177 / 20.5
>>788 CFM

>Is your formula ordered as follows?
>A) 237 x 20 x 3.412 / 19 x 1.08 = 919
>which is the same as 237 x 20 x 3.412 x 1.08 / 19 = 919
>or is it
>B) 237 x 20 x 3.412 / (19 x 1.08) = 788

Neither. It's (237 x 20 x 3.412 ) / (19 x 1.08) = 788

>Remember your math rules from school?

>Rule 1: First perform any calculations inside parentheses.
>Rule 2: Next perform all multiplications and divisions, working from
>left to right.
>Rule 3: Lastly, perform all additions and subtractions, working from
>left to right.

Please don't lecture me on math rules. Thank you.

Posted by Jean on February 20, 2009, 10:57 pm

On Fri, 20 Feb 2009 22:40:29 -0500, The King

>>On Fri, 20 Feb 2009 21:12:20 -0500, The King

>>>Lets plug your numbers into this and tell me what you get.
>>>CFM = volts x amps x 3.412 / 1.08 x temperature rise
>>>= 237 x 20 x3.412 / 1.08x 19
>>>=16177 / 20.5
>>>788 CFM

>>Is your formula ordered as follows?
>>A) 237 x 20 x 3.412 / 19 x 1.08 = 919
>>which is the same as 237 x 20 x 3.412 x 1.08 / 19 = 919
>>or is it
>>B) 237 x 20 x 3.412 / (19 x 1.08) = 788

>Neither. It's (237 x 20 x 3.412 ) / (19 x 1.08) = 788

Which is identical to B)

>>Remember your math rules from school?
>>Rule 1: First perform any calculations inside parentheses.
>>Rule 2: Next perform all multiplications and divisions, working from
>>left to right.
>>Rule 3: Lastly, perform all additions and subtractions, working from
>>left to right.

>Please don't lecture me on math rules. Thank you.

Can you give me a URL that has your formula? I'll need it to back up
your calculations. "Some guy on a newsgroup" won't hold much sway.

I do appreciate your help. And I realize this air flow business is not
really consequential to solving my problem.

Posted by The King on February 20, 2009, 11:14 pm

>On Fri, 20 Feb 2009 22:40:29 -0500, The King

>>>On Fri, 20 Feb 2009 21:12:20 -0500, The King
>>>>Lets plug your numbers into this and tell me what you get.
>>>>CFM = volts x amps x 3.412 / 1.08 x temperature rise
>>>>= 237 x 20 x3.412 / 1.08x 19
>>>>=16177 / 20.5
>>>>788 CFM
>>>Is your formula ordered as follows?
>>>A) 237 x 20 x 3.412 / 19 x 1.08 = 919
>>>which is the same as 237 x 20 x 3.412 x 1.08 / 19 = 919
>>>or is it
>>>B) 237 x 20 x 3.412 / (19 x 1.08) = 788

>>Neither. It's (237 x 20 x 3.412 ) / (19 x 1.08) = 788

>Which is identical to B)

Exactly.

>>>Remember your math rules from school?
>>>Rule 1: First perform any calculations inside parentheses.
>>>Rule 2: Next perform all multiplications and divisions, working from
>>>left to right.
>>>Rule 3: Lastly, perform all additions and subtractions, working from
>>>left to right.

>>Please don't lecture me on math rules. Thank you.

>Can you give me a URL that has your formula? I'll need it to back up
>your calculations. "Some guy on a newsgroup" won't hold much sway.

Ahem.. some guy?? I'm the God damn KING here! You tell them I said
so.

Try Googling Sensible Heat Equation and Total Heat Equation or some
variable of such. I'm sure its out there somewhere. Check the
Engineering Toolbox they may have something.

>I do appreciate your help. And I realize this air flow business is not
>really consequential to solving my problem.

The problem is Goodman is just shit equipment. Its always been loud.
That's why they say its normal. Wanna fix it. Junk it and get
something better. I know you don't want to hear that and they will
never say it but that's the facts Jack.

It's either that or engineer a Cone of Silence for it in your spare
time. :)

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