Types
A thermostat that can operate a cooling system and a heating system. Also called heating- cooling thermostat.
What is a combination thermostat?
A smaller version of an ECM motor that uses a permanent magnet rotor.
What is a brushless DC motor?
block DC because their plates are separated by an insulating dielectric. However, in AC, the alternating voltage causes the capacitor to charge and discharge repeatedly, allowing current to effectively “flow” as displacement current.
What is capacitor?
A simple circuit that has only one path for current flow, and the current travels from one load to the next.
What is a series circuit?
I am the first to create the electric battery.
Who is a Alesandro Volta?
A thermostat that can operate a cooling system and a heating system. Also called a combination thermostat.
What is a heating-cooling thermostat?
A motor that uses a high resistance (dc) start winding to split the phase.
What is a resistance-start, induction-run(RSIR)?
a heavy-duty electrical switch in your air conditioner or heat pump that acts as a remote-controlled bridge, using low-voltage signals from the thermostat to turn the high-voltage power on or off to the compressor and fan motor, managing the entire cooling cycle by allowing or blocking electricity flow.
What is a contactor?
The law that states the sum of the voltage drops in a series circuit equals the source voltage.
What is Kirchnoff voltage law?
I am the letter C on a schematic
What is the abbreviation for Contactor?
A thermostat that can remember an occupant’s desired set point and adapt the HVAC system operation to automatically program On and Off cycles and temperature set points.
What is learning thermostat?
A small resistance coil used by a thermostat to produce enough heat to keep the thermostat warmer than the ambient temperature so the thermostat will cycle off the heat before reaching the cut-out temperature and avoid system overshoot.
What is a heat anticipator?
crucial component that steps down high voltage (like 120V/240V) to low voltage (typically 24V) to safely power the system's controls, such as the thermostat, control board, and relays, while the high voltage runs the main motors and compressors, acting as an essential power converter for the entire system. They work via magnetic induction and are vital for system operation, often failing due to age, power surges, or overloads, and can be diagnosed with voltage or continuity tests.
What is a transfomer
A simple circuit that has more than one path for current flow.
What is a parallel circuit?
I am XFMR.
What is the abbreviation for Transformer?
A thermostat that typically operates using either 120 Vac or 240 Vac.
What is a line-voltage thermostat?
A type of large-value capacitor that can achieve very high capacitance.
What is electrolytic?
fan switching relay is an electromagnetic switch, common in HVAC systems, that uses a low-voltage signal (like from a thermostat) to control higher-voltage power for a fan.
What is a general purpose switching relay
Each individual path that makes up a circuit.
What is a branch?
Lock out/tag out
What is LOTO?
A thermostat that operates at 24 Vac supplied by a step-down transformer. It often uses relays to switch line voltage circuits on and off.
What is a low-voltage thermostat?
Capacitors with positive polarity.
What is polarized?
In a heating system, a safety control that ensures that a measured temperature does not exceed a certain level.
What is a temperature limit switch?
A combination of series and parallel circuits. Also known as combination circuits and series-parallel circuits.
What is a combination circuit?
I am 24v on this side only.
How many volts can the side of a contactor hold?
A heating thermostat that operates a small solenoid valve powered by a very small voltage produced by a thermocouple device sensing a standing pilot light. These may only be used in systems having a standing pilot.
What is a millivolt thermostat?
A single-phase motor capacitor that assists a motor in starting up.
What is a start capacitor?
electrically operated switches that open and close the circuits by receiving electrical signals from outside sources.
What is a relay?
Small diameter 18 AWG wires that are generally used in home and light commercial wiring.
What is solid wire?
In a wire bunch of thermostat wire, i am on the wire that should never lose power to it
What is the R terminal.
A thermostat that can control a system’s heating and cooling capacity through various means, such as modulating compressor and fan operation or varying fuel combustion or electrical power
What is a multistage thermostat?
In basic terms, a sensing device that reacts to temperature change. More broadly, a temperature control that starts and stops an HVAC system when preset temperature conditions are reached
What is a thermostat?
The tstat acts as a _________________between R terminal and the other the other terminals.
What is a switch?
An electronic thermostat that draws a small amount of electrical power from the low- voltage side of an HVAC system’s control circuit to operate the thermostat’s electronics.
What is a power-stealing thermostat?
a time-delay relay that controls the orderly startup of components in electric heating systems, like furnaces or heat pumps, preventing electrical overload by staggering the activation of heating elements and the blower fan, using internal bimetal elements and contacts to manage power flow over time. It ensures components turn on and off in a set sequence, with specific delays for each stage, enhancing safety, efficiency, and preventing system trips.
What is a sequencer?
During heating mode, the furnace tstat connects the R terminal to_
What is the W terminal
A thermostat that contains a microprocessor that functions as a clock and allows the user to select different conditions for different blocks of time.
What is a programmable thermostat?
A thermostat that can be controlled wirelessly from anywhere in the home or the world.
What is a Wi-Fi enabled thermostat?