"Not with Copeland compressors.
I have built 2-ton DH's withe Copeland (coplemetec)
pumps, rated at 3 HP, R-12, 2 tons, medium-to-high temp.
Of course, that was many years ago, and these were salvaged from
But three phase exists all the way down to fractional horsepower, if
you need it. Price is the main stickler. Go with what is cheaper
(and cheaper to repair/replace, etc).
The reason you don't see too many residential 3-PH units under 5 tons,
is 3-PH power is rare in residential services, so there is little
call for it. But 3-PH motors and compressors are readily available,
all the way down to two tons or less. Fifteen to Thirty years ago,
3-PH motors were generally cheaper than single PH. Now, I dunno. I
don't do it no more.
Grab the latest Grainger catalog, and see what compressors are
available, and for what prices. "
Yeah he could build his own air conditioner from parts he got at
Grainger. But he wants to BUY one that is already made, from Lennox or
Trane or Carrier, etc. THEY don't make many 3 phase units less than
three ton. THAT was the question. I realize it COULD be done, but a
homeowner isn't likely to do it, it would make no economic sense. I
don't make my own units either. cheaper and easier and better to buy
one from a major manufacturer.