Week 4 Unit Mini Splits

List ways that mini-split systems differ from traditional ducted split systems.

• Traditional split systems split the unit into two parts. They are intended to condition a large area using ductwork to distribute the heating and cooling to different areas of a building. Mini-split systems are split into two parts like a traditional split system, but they are sized to condition areas between 9,000 BTU/hr and 36,000 BTU/hr. They do not use ductwork; the indoor coil is mounted in the room being conditioned.

• No ducts the evap is in the room

List the types of indoor units available for use in mini-split systems.

• Indoor units for mini-split systems are available in several styles to fit different applications, including wall mount, ceiling suspended, compact cassette, floor mount, low static ducted, and high-static ducted.

• Used as main ac source in most foreign countries

Where is the metering device usually located on a mini-split system?

• The metering device in most mini-split systems is located outside, not inside as with a traditional system.

• Short trip to head units usually. There are some mini splits with metering device on evap head.

Why are both lines of a mini-split system insulated?

• Both refrigerant lines must be insulated because they are both low pressure and cold in the cooling mode.

• yep

How are the refrigerant lines of a mini-split system connected to the unit?

• Flare connections are used on mini-split systems to avoid oxidation in the lines and also to avoid heating and destroying the sensitive electronic expansion valves used in the outdoor units.

• Use a torque wrench

What is the difference between a flare made for older refrigerants, such as R-22, and a flare made for R-410a?

• The flares on systems using R-410A are designed for high pressure. The flare nuts have thicker walls, a 45° angle, and the flared ends of the tubing are a little larger in diameter than regular flares

• Very few r22 in operation and can no longer be sold

Why do many mini-split system installations require a condensate pump?

• Tiny condensate pumps designed specifically for minisplit systems are required for installations where a gravity drain is not possible. Some indoor units, such as the ceiling mount or ceiling cassette cannot use a gravity drain because a gravity drain would have to come straight down in the middle of the room. These units typically come equipped with a condensate lift kit to lift the condensate out of the unit into a drain.

• Small version of a normal one, just fits in case of Head Unit

Describe how a two-piece condensate pump works.

• The reservoir installs in the back of the unit and the pump somewhere away from the pump, such as in the attic.

• For smaller system

How are a mini-split systems typically wired?

• All power for the unit is supplied outside. Power to operate the indoor blower and controls comes from the outdoor unit. Four wires are usually run from the outdoor unit to the indoor unit. One wire carries power, a second wire carries low voltage communication, while a third wire carries both line voltage power and low-voltage communication. A fourth wire is utilized for ground.

• There are some 120v mini splits, usually 1.5 tons or less

What type of controls do most mini-split systems use?

• Most mini-split systems use communicating controls. They do not operate by the absence or presence of 24 volts, but by the commands sent over the communicating wires. Most mini-split systems use infrared remote controls for temperature settings, blower speed, and programming setup and setback scheduling. Hard-wired controls are sometimes available as an option.

• TV remote like, and moderns have bluetooth or wifi for remote control