When a thermostat displays ‘Auxiliary Heat,’ it indicates that an additional heating source is being activated to maintain the set temperature, typically because the primary heat pump system alone cannot meet the demand.
In the context of HVAC systems, ‘AC Hold’ refers to a setting on a thermostat that maintains a constant temperature regardless of a programmed schedule. It overrides automatic adjustments to keep the environment at a fixed set point.
Airwave is a specialized energy-saving feature on certain Nest thermostats that manages cooling by utilizing fan-only circulation. It aims to maintain comfort while reducing the active runtime of the air conditioning compressor.
In air conditioning, a “ton” is a unit of cooling capacity equal to 12,000 British Thermal Units (BTU) per hour. It originates from the amount of heat required to melt one ton (2,000 pounds) of ice over 24 hours. This measurement helps consumers and professionals size HVAC equipment appropriately.
The “Hold” function on an air conditioning unit (or thermostat) locks the current temperature setting indefinitely, overriding any programmed schedule. It is used to maintain a constant temperature regardless of the time-of-day or day-of-week settings, providing manual control over the HVAC system.
The dry mode on an air conditioner is a setting designed primarily to reduce humidity in a room without significantly lowering the temperature. Unlike cooling mode, the fan and compressor run intermittently to remove moisture from the air, making the environment more comfortable in humid conditions.
On MRCOOL HVAC systems, the code DF typically indicates Defrost mode. This is a normal operation cycle where the heat pump temporarily reverses to melt ice on the outdoor coil. It is not usually an error code requiring service.
CFM stands for Cubic Feet per Minute, a measurement of the volume of air a blower can move over a specific period. It is a primary metric used to determine the airflow capacity and efficiency of fans, blowers, and ventilation systems.
A blinking ‘Cool On’ indicator on a thermostat or HVAC control panel typically signifies a delayed start or a system fault. It often indicates that the system is in a protective time-delay mode or has encountered a mechanical error.
Heating auxiliary refers to a secondary or supplemental heat source used to assist a primary heating system. It is most commonly encountered in heat pump systems to maintain temperature during extreme cold.