Duct Work
Ductboard duct sections are fabricated from which material?
The applied voltage (the voltage that the unit will actually be using) should be within ±_____% of the rated voltage of the unit.
10 +/-
On a new package system, the refrigerant charge is
added to the system at the factory
A float switch, located in an auxiliary drain pan, is typically wired to
open the low-voltage control circuit.
When installing the condensing unit of a split-system, it should be
set on a concrete or high-impact plastic pad.
Square duct or rectangular duct is assembled with
“S” fasteners and drive clips.
The standard wire size for light-duty low-voltage wire is
18 gauge.
When sizing and selecting air conditioning equipment, which of the following must be taken into account?
Moisture content
The condensing unit of a split-type air conditioning system is made up of the
condenser coil and compressor.
On a line set used to install a split-system, the ______ line is insulated.
suction
To help create an airtight seal between duct sections
mastic may be applied
The __________ provides installation standards, wire sizes, methods of routing wires, and types of enclosures for wiring and disconnects.
National Electrical Code (NEC)
Package-type air conditioning units are intended to be located
either on the roof of a structure or at ground level.
When measuring voltage across an open safety switch (like a tripped high-limit switch) while the system is calling for heat, what voltage should you read?
24V AC. (Because the switch is open, you are measuring the potential difference across the break in the line).
The condenser of a split-system typically contains enough refrigerant for ____ ft of line set.
25
When joining two sections of fiberglass ductboard
staples and tape are used.
In a standard single-stage heating and cooling system, which terminal controls the indoor blower fan, and what color wire is typically used?
G terminal, typically using a Green wire.
What refrigerant lines are field installed on the typical package-type air conditioning unit?
Package-type equipment has no field-installed refrigerant lines.
What is the industry-standard color and terminal designation for the continuous 24V power supply from the transformer?
Red (R).
After installing the refrigerant lines on a split-system, the next step would be to
pressurize the system with nitrogen for a leak test.
A typical multihead, ductless split system is configured with
multiple indoor units and one outdoor unit.
What is the difference between the O and B terminals on a heat pump thermostat?
Both control the reversing valve. O energizes the reversing valve in cooling mode. B energizes the reversing valve in heating mode.
The two types of heat transfer that are facilitated by the evaporator are
sensible heat and latent heat.
Question 3: What is the purpose of the "C" terminal, and why is it required for modern smart thermostats?
The Common (C) wire completes the 24V AC circuit, providing continuous power to the thermostat's internal electronics without relying on batteries or power-stealing.
Line sets typically come in standard lengths of
25 and 50 ft.