Aprilaire Zone Board 4 Heat & 2 Cool 2 stage 3 Zone Heat Pump & Gas System Kit Model # 6403K

Description

The AA6403K is a heat pump from Aprilaire stocked by Buy Comfort Direct — full listing: Aprilaire Zone Board 4 Heat & 2 Cool 2 stage 3 Zone Heat Pump & Gas System Kit Model # 6403K. This page covers what it is, where it fits in a system, what to check before you order, and how it ships.

About the AA6403K

Where the AA6403K fits

A heat pump is an air conditioner that can run in reverse: in winter it pulls heat from outdoor air and moves it inside, which is far cheaper than resistance heat in most of the country. The AA6403K pairs with a matched indoor coil or air handler, and in cold climates it is often installed dual-fuel with a gas furnace that takes over below the balance point.

Inverter (variable-capacity) heat pumps modulate output to match the load, which keeps the house closer to setpoint, runs quieter and pulls the best efficiency numbers; single-stage units cost less up front and are simpler to service. Both need a matched indoor coil to hit their ratings.

Background reading: the U.S. Department of Energy heat pump guide.

What to check before you order

• Tonnage from a load calculation; SEER2 and HSPF2 for your climate.
• Matched indoor coil or air handler with the same refrigerant (AHRI-listed pairing).
• Thermostat with an O/B reversing-valve terminal, or a dual-fuel thermostat if pairing with a furnace.
• Electrical service, pad, disconnect and line set (sold separately).

Installation and service notes

Outdoor heat pumps sit on a pad raised above snow and grass level with clearance for defrost water to drain, a disconnect within sight, and a line set sized and run within the manufacturer’s length and lift limits. Commission it in both heating and cooling modes and confirm the reversing valve and defrost cycle operate before you leave.

Why buy the AA6403K from Buy Comfort Direct

We are a stocking HVAC distributor based in Winder, Georgia — not a marketplace reseller. Orders over $99 ship free, and financing is available at checkout through Affirm. If you are not sure this is the right part, call (877) 843-4822 before you order and we will match it to your equipment. Browse the rest of our Aprilaire Zoning, and see what customers say on our reviews page.

Ordering and delivery

In-stock items ship from our Winder, Georgia warehouse. Orders over $99 ship free; large equipment travels by freight carrier and parts by ground, and you will get tracking by email when it leaves. Need it matched to a system, or need a quantity that is not on the shelf? Use the contact page or call (877) 843-4822 and we will confirm availability before you pay.

AA6403K FAQ

Will a heat pump keep up in winter here?

In Georgia and most of the Southeast, yes, with backup heat for the coldest nights. Further north, dual-fuel with a furnace is the usual answer.

Does the AA6403K ship free?

Yes on orders over $99 — most orders that include it qualify. Large equipment ships by freight carrier; parts ship by ground.

How do I know it matches my equipment?

Send us your equipment model number through our contact page or call (877) 843-4822. We check the pairing before it ships.