Parts
This simple disposable part protects the evaporator from dirt.
What is a filter?
This common residential fuel source powers most furnaces in the U.S.
What is natural gas?
This type of packaged rooftop unit is common in commercial buildings and typically contains heating and cooling in one package.
In low voltage HVAC diagrams, this wire controls cooling.
What is the Y wire?
This is the first step when the system isn't cooling.
What is ensuring the system has power?
This motor type adjusts it's speed automatically to maintain airflow and is common in modern furnaces.
What is a Variable speed/ECM motor?
A split system has two main components, the indoor air handler and this outdoor component.
What is the Condenser unit?
VAV systems use these devices to regulate airflow at each zone.
What is a dampener?
This symbol on a wiring diagram represents a switch that opens on a high temperature.
What is a heating thermostat.
If a system trips on high pressure, this components airflow should be checked for blockage.
What is the condenser unit?
This devices restricts refrigerant flow and can be fixed or adjustable.
What is a metering device?
This component in a forced-air heating system circulates heated air throughout the home, often referred to as the "heart" of the system.
What is the indoor blower motor?
Economizer use outdoor air to provide "free cooling" based on this condition.
What is outdoor air being cooler than the indoor temperature?
Ladder diagrams read left to right for control power and top to bottom for this type of logic flow.
What is operational/logic flow?
Frost buildup on the evaporator coil indicates what?
What is low airflow or a refrigerant related issue?
In a heat pump, this outdoor component changes the flow of refrigerant.
What is a reversing valve?
This efficiency rating measures how well an air conditioner uses electricity during a typical cooling cycle.
What is the Seasonal Energy Efficiency Ratio (SEER)?
This type of mechanical chiller removes heat from water by mechanical refrigeration.
What is a water-cooled chiller?
This device shown in series with the compressor protects it from overheating.
What is a thermal overload.
When a compressor hums but doesn't start what component is likely to have failed?
What is the starting capacitor or relay?
Scroll compressors are preferred over reciprocating ones because they have fewer of these moving components.
What are sprial scrolls?
Two stage variable speed systems improve comfort by extending these.
What are heating and cooling cycles?
Large commercial systems often use this variable refrigeration approach allowing simultaneous heating and cooling in different areas.
What is variable refrigerant flow?
These diagrams show refrigerant and component layout rather than eletrical circuitry.
What are piping diagrams?
A system with normal suction pressure but low head pressure may be experiencing this.
What is a failed metering device?