- Thread starter tom baker
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My thoughts too. The 036 in the Model No. is a clueLook for the cooling capacity in BTU per hour. 12000 BTU per hour is 1 ton of cooling.

At a guess I'd say the unit is 36000 BTU per hour and thus 3 tons of cooling, just from the model number, not from any real knowledge.

https://dms.hvacpartners.com/docs/1009/Public/00/SS-PH12-07.pdf

Please search the web using the model #. My search yielded 34,400 BTUh rating (036-B) or a TC of 2.87 tons. Here.I have a Payne Heat pump and would like to know how many "tons" capacity it is. its a

Product PH12NA036000ABAA

Model PH12NA036-B

About ten years old and I have the manual but not sure what to look for

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Below 2-tons, you'll usually just see the BTUs listed, and these would typically be window or mini-split systems. After those, the residential world is divided into tonnage as 2, 2.5, 3, 3.5, 4, and 5. Multiply by 12 and that's the number you'll usually find in the model number.

Short pounds or long pounds?Last week wired up an 18,000 BTU mini-split and it only weighed about 300 pounds

Um, no. "12,000 BTU/hour" isn't even a measure of heat; it's a measure of power. The amount of heat that needs to be removed from a ton of water to turn it into ice is closer to 300 kBTU than twelve. And it's... 12,000 BTU/hr is the heat that needs to be removed from water to make a ton of ICE.

About a century and a half ago, in the early days of mechanical refrigeration, icehouse operators asked refrigeration salesmen, "What'll this do for me?" Their response: "This machine will provide the same cooling effect as consuming a ton of ice every day." And the refrigeration ton was born.

But we no longer use icehouses. It would be a good thing if we also quit using refrigeration tons.

(HVACR engineers are among the slowest to adopt new ideas ... if something introduced in 1799 can still be considered "new". Many of them still use Roman Numeral prefixes.)

<rant>

One more example of a good reason to ditch the British system of weights & measures and use metric.

In the metric system, there are only seven base units to learn and just ONE unit of refrigeration capacity, the Watt, (or kilowatt, megawatt, et at.) No confusion and no need for unit conversion.

(there's also ONE unit of efficiency, the dimensionless ε -- no need to fart around with EER, SEER, COP or kW/ton)

https://en.wikipedia.org/wiki/Intern...ystem_of_Units

</rant>

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Multiply torque (in kiloNewton-meters) by speed. (in radians per second) The result is the engine's power output in kilowatts.I don't understand how an engine is rated in Kw.

The Watt is a measure of power. All flavors of power, not merely electric power.

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Yes, thanks for the good clarification - I should have been more specific - e.g makes 1 ton of iceShort pounds or long pounds?

Um, no. "12,000 BTU/hour" isn't even a measure of heat; it's a measure of power. The amount of heat that needs to be removed from a ton of water to turn it into ice is closer to 300 kBTU than twelve. And it'sBTU, notBTU per hour.

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</rant>

Yes, it has it's merits and I've been advocating that on here for years!<rant>

One more example of a good reason to ditch the British system of weights & measures and use metric.

In the metric system, there are only seven base units to learn and just ONE unit of refrigeration capacity, the Watt, (or kilowatt, megawatt, et at.) No confusion and no need for unit conversion.

(there's also ONE unit of efficiency, the dimensionless ε -- no need to fart around with EER, SEER, COP or kW/ton)

Just one small correction. Although commonly, and incorrectly, called metric, it is SI. (Système Internationale d'Unités,)

You can't measure Joules by the metre.

Just one small correction: "its" has no apostrophe when used as a possessive pronoun.

Besoeker3 said:Yes, it has it's merits and I've been advocating that on here for years!

Just one small correction. Although commonly, and incorrectly, called metric, it is SI. (Système Internationale d'Unités,)

You can't measure Joules by the metre.

You are correct. No apostrophe. I don't normally make many grammatical mistakes. Please accept my apology.Nothing wrong with "metric system." Metrics are measurements of things, not necessarily lengths. You can use a formal foreign name if you wish, but it's not incorrect to use a name that more people actually understand.

Just one small correction: "its" has no apostrophe when used as a possessive pronoun.

But the term "metrics" has a different meaning to "metric system".

Anyway, I'm an old fellow. I grew up with Imperial measures. Yards, feet, inches, chains, furlongs, leagues, bushels, acres, etc. At secondary school (age eleven onward) science was in the CGS system. Centimetre, gram, second. Later, and at university, we had MKS. Then SI. All my engineering calculations used that.

But we Brits still want Imperial units for some things. Ask someone their height and you will most likely get an answer in feet and inches, their weight in stones and pounds.

An interesting anomaly is found at the British pub. If I have a beer, it is sold by the pint. My dear wife has a wine and that's measured in millilitres.

Right you are. I took a wild guess that this audience -- particularly the Americans here -- would vaguely recognize the "metric" system, but have an eyes-glaze-over moment were I to mention SI.... Just one small correction. Although commonly, and incorrectly, called metric, it is SI. (Système Internationale d'Unités,) ...

When I am told _use metric_ and then have to deal with 'pressure' in kg/cm^2, or speed in km/hr my CDO goes haywire (CDO, its kinda like OCD, but the letters are in proper order....)

And then I remember that while SI is a self consistent system of units, the units themselves are pretty arbitrary and their selection quite political. Think about our unit of length; given what we know now, using the distance light travels in 1/1,000,000,000 second _exactly_ as the unit of length would be much nicer than the distance light travels in 1/299,792,458 second.

Sorry, just rambling

Ramble on, sir.When I am told _use metric_ and then have to deal with 'pressure' in kg/cm^2, or speed in km/hr my CDO goes haywire (CDO, its kinda like OCD, but the letters are in proper order....)

And then I remember that while SI is a self consistent system of units, the units themselves are pretty arbitrary and their selection quite political.

Sorry, just rambling

But can you shed a light on why you think the units have a political aspect?

'The nice thing about standards is that you have so many to choose from.'Ramble on, sir.

But can you shed a light on why you think the units have a political aspect?

One critical aspect of units of measurement is how technically sound they are, how reliably they can be implemented or derived from basic physical quantities, how self consistent the units are, etc. By this metric, SI is hands down better than imperial units.

But a separate critical aspect is how well you can convince people to _use_ the same system of units. And convincing people to _use_ units is at its core a political act.

Is there any _technical_ benefit to making 0 longitude Greenwich rather than Paris? That selection was politics.

Is there any _technical_ benefit to the particular unit of length used in SI?

Sometimes the politics is in a very small group of people, eg. the recent vote to redefine the kilogram in terms of Plank's constant rather than something else.

IMHO technical standards are by their nature political things, and this is true for standards for units of measure.

-Jon