Appendix A: Glossary - Crestron CHV-TSTAT Operation And Installation Manual

Thermostats

Appendix A: Glossary

34 • Thermostats: CHV-TSTAT and CHV-THSTAT
Crestron CHV-TSTAT and CHV-THSTAT
Anticipators – Used to anticipate the drop or rise in temperature and energize the
appropriate system before reaching the set point.
Balance Point – The lowest outdoor temperature at which the refrigeration cycle of a
heat pump will supply the heating requirements without the aid of a
supplementary heat source.
Blower (Fan) – An air-handling device for moving air in a distribution system.
BTU - British Thermal Unit – In scientific terms, it represents the amount of energy
required to raise one pound of water one degree Fahrenheit. One BTU is the
equivalent of the heat given off by a single wooden kitchen match.
Call – A call is when the thermostat requests the heating or cooling system to turn on.
Damper – Found in ductwork, this movable plate opens and closes to control airflow.
Dampers are used effectively in zoning to regulate airflow to certain rooms.
Dead Band – The minimal differential between Heating and Cooling.
Dual Fuel – A heat pump used in conjunction with an existing furnace.
Emergency Heat (Supplementary Electric Heat) – The auxiliary or emergency heat
provided at temperatures below a heat pump's balance point. It is usually
electrical resistance heat.
Forced Air – A type of heating system that uses a blower motor to move air through
the furnace and into the ductwork.
Furnace – Equipment used to convert heating energy, such as fuel, oil, gas or
electricity, to usable heat. It usually contains a heat exchanger, a blower and
the controls to operate the system.
Heat Exchanger – A device for the transfer of heat energy from the source to the
conveying medium of air or water. Most common combinations are:
Refrigerant to air or Refrigerant to water (DX), Water to air (hydronic),
Steam to air, Steam to water.
Heat Pump – A unit that both cools and heats. A heat pump system can be either a
split system or a packaged system. A heat pump can be used in conjunction
with a gas/oil/LP furnace (using the furnace instead of electric resistance heat
when temperatures fall below about 35 F).
Humidity – The total amount of moisture in air. Relative humidity (RH) is the
amount of moisture in air, relative to its total capability based upon its
temperature (dewpoint). Moisture will condense on surfaces that are below
this dewpoint.
HVAC – Heating, ventilation and air conditioning.
Setpoint – The thermostat temperature set to begin heating or cooling.
Time Delay (Timer Guards) – Refers to a safety device or circuit that will not allow
restart for 5 minutes.
Two Stage Heating/Cooling –The heating or cooling unit starts out running in its
first stage, and operates at about 68% of its capacity. When the temperature
outside goes very low or very high, the system adjusts to full capacity
(second stage) to meet the demand.
Operations and Installation Guide – DOC. 8163