Sequence of Operation
ReliaTel Control Cooling without an Economizer
When the system switch is set to the "Cool" position and the zone temperature rises above the cooling setpoint control band, the RTRM energizes the modulating eFlex compressor starting with the minimum compressor motor speed and runs through a start-up sequence for that compressor, provided the low pressure control (LPC4), high pressure control (HPC3), and the discharge line thermostat (DLT3) are closed. When the eFlex compressor and the outdoor fan motor are energized, they adjust motor speeds in order to maintain the zone temperature (Single Zone VAV) to within +/-0.5°F or Supply Air Temperature (Multi Zone VAV) to within ±1°F of the sensor setpoint at the sensed location.
If the modulating compressor at its maximum capacity cannot satisfy the cooling requirement, the RTRM energizes the first fixed speed compressor, provided the low pressure control (LPC1), the high pressure control (HPC1), and the discharge line thermostat (DLT1) are closed, while simultaneously reducing the modulating compressor motor speed to allow a smooth transition in system capacity. When the fixed speed compressor is energized, the ReliaTel control starts to maintain the zone temperature (Single Zone VAV) to within +/-0.5°F or Supply Air Temperature (Multi Zone VAV) to within ±1°F of the sensor setpoint at the sensed location by modulating the eFlex compressor speed and both ODM.
If the first two compressors cannot satisfy the load, the second fixed speed compressor is energized in addition to the first fixed speed compressor, provided the low pressure control (LPC1), the high pressure control (HPC2), and the discharge line thermostat (DLT2) are closed. Simultaneously, the modulating compressor speed is reduced for a smooth transition to the higher system capacity. When the third compressor is energized, the ReliaTel control starts to maintain the zone temperature (Single Zone VAV) to within +/-0.5°F or Supply Air Temperature (Multi Zone VAV) to within +/-1°F of the sensor setpoint at the sensed location by modulating the eFlex compressor motor speed and both ODM.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.