Water coil
Sized for the cold end of the loop
On a closed loop, output falls as incoming water gets colder. Polar Bear puts that
drop at 10–20% against 20–30% or more for other makes, because the water coils carry
more heat-transfer surface. The tube is formed in a clover-leaf with up to eight
convolutions — which also means that if it ever does freeze, it expands rather than
splits.
Air coil
Rifle tubing and lanced fins
Oversized across the range, 1 ton to 10 ton. More surface area is the whole trick: it
raises output and efficiency, and in cooling mode the oversized coil is what gives you
serious dehumidification rather than a cold, clammy house.
Fan
ECM, five speeds, twenty-second ramp
Super Low and Medium Low run for pennies a day, giving continuous filtration and even
temperatures. Fans ramp gently over about twenty seconds, so no banging ductwork. In
humid weather the fan deliberately slows to pull more moisture out.
Cabinet
Stainless condensate pan, 1″ acoustic lining
Galvanized pans rust and plastic ones crack; stainless does neither. The acoustic
lining is double what competitors use — you should not be reaching for the TV remote
when it starts. Pipe penetrations get rubber grommets, against vibration and against
electrolysis between copper and steel.
Circulators
Wilo, stainless shafts, brass flanges
Wet-rotor circulators with stainless steel shafts rather than ceramic, which break.
Brass flanges rather than cast iron, which rusts and can snap if over-tightened. Type L
copper — thicker wall than the usual — internally.
Hot water
Desuperheater, roughly half your water heating
A 6,000 BTU double-wall coil takes the hottest heat straight off the compressor into
your hot water tank. Supplemental in heating mode, effectively free in cooling mode.
Its circulator is 100% bronze because it is in the potable circuit.