Mark Pauletti suing a remote to check airflow for How to Install a Mini-Split Heat Pump
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How to Install a Mini-Split AC Heat Pump

An easy-install way to provide cooling and heating without ducts—and no window units

Q: How can we cool the room over our garage in the summer and warm it in the winter? No space heaters or window AC units, please! — Nadine Syrett, Williamsburg, Va.

A: Richard Trethewey replies: Sounds like you need a mini-split heat pump, which provides cooling and heating fairly unobtrusively without using ducts. It pushes refrigerant from an outdoor condenser directly to a wall-mounted air handler that blows hot or cold air into the room. Because there are no ducts to retrofit, the system is simple for a pro to install. And it provides excellent dehumidification, quiet operation, and great efficiency. Need to adjust the temperature or turn the unit off? Just use the remote control.

A single air handler can heat or cool up to 1,000 square feet, depending on the climate and system size. (In heating mode, it functions down to minus 13 degrees F, not a problem where you live.) For larger spaces, up to four independently controlled indoor units can connect to one condenser, for the ultimate in zoned comfort.

Pictured: Mark Pauletti of Arctic Mechanical, in Port Chester, New York, uses the remote to check the airflow from the indoor unit.


Steps // How to Install a Mini-Split AC Heat Pump
1 ×

Install the Condenser

 
Step One // How to Install a Mini-Split AC Heat Pump

Install the Condenser

Install the Condenser for How to Install a Mini-Split Heat Pump
Photo by Ryan Benyi

This unit should go in a shaded location outside the house where it can have at least 4 inches of clearance behind it and 20 inches of clearance above it and in front of it. The 119-pound unit can be mounted on brackets fastened to the wall, as shown, or bolted to concrete blocks resting on the ground.

 
2 ×

Locate the Air Handler

 
Step Two // How to Install a Mini-Split AC Heat Pump

Locate the Air Handler

Locate the Air Handler for How to Install a Mini-Split Heat Pump
Photo by Ryan Benyi

It mounts on an exterior wall no more than 33 feet from the outdoor unit, at least 2⅛ inches below the ceiling and 3 feet from a TV. First, the mounting plate is screwed to the studs, as shown. At the plate's lower-right corner, the installer drills through the wall with a 3-inch hole saw. Outside, a connecting hole is drilled ¼ inch below the one inside.

 
3 ×

Mount the Air Handler

 
Step Three // How to Install a Mini-Split AC Heat Pump

Mount the Air Handler

Mount the Air Handler for How to Install a Mini-Split Heat Pump
Photo by Ryan Benyi

With the cover off, the control wire, refrigerant lines, and condensate drain hose are attached to the unit and taped together, and a protective sleeve is fitted into the hole in the wall. The unit is hoisted up without its fins being touched, and the taped parts are fed through the sleeve, as shown. The unit then mounts to the plate.

 
4 ×

Set Up the Condenser

 
Step Four // How to Install a Mini-Split AC Heat Pump

Set Up the Condenser

Set Up the Condenser for How to Install a Mini-Split Heat Pump
Photo by Ryan Benyi

The outdoor unit is connected to the control wire from the indoor unit and to a jacketed power cable leading to the breaker panel. Then the ends of the refrigerant lines are fastened to the condenser with flare nuts, as shown. Flare nuts are also used to join these lines to the ones on the indoor unit.

 
5 ×

Hide the lines

 
Step Five // How to Install a Mini-Split AC Heat Pump

Hide the lines

Hide the lines for How to Install a Mini-Split Heat Pump
Photo by Ryan Benyi

A plastic channel screwed to the siding hides the lines, condensate hose, and control wire. After the hose is checked to make sure it drains freely, the end of the hole sleeve is sealed with silicone to prevent water infiltration. Then the channel is capped, as shown.

 
6 ×

Pump and Cover

 
Step Six // How to Install a Mini-Split AC Heat Pump

Pump and Cover

Pump and Cover for How to Install a Mini-Split Heat Pump
Photo by Ryan Benyi

A gauge manifold and a vacuum pump are hooked up to the refrigerant lines to detect leaks and dry the lines as refrigerant is pumped into them. The last step is to put the cover on the air handler, as shown. The system is then ready to heat and cool.

 
 
 

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