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. Refer to appropriate unit wiring diagrams for control connections. If during the the 90 minute period the refrigeration cycle changes from one state to the other based on a call from a temperature controller or humidity sensor, the timer is reset and starts counting again. During a cooling or dehumidification cycle, if the given cycle remains in that state for 90 accumulated minutes without changing to the other state, a purge time algorithm in the RTRM, will force the system to switch to the other state for three minutes. In addition to the normal sequence of events, there is a purge sequence in the ReliaTel RTRM module that changes the state of the refrigeration cycle. In other words, 2nd stage cooling take priority over a call for dehumidification. The three-minute minimum on and off times are still active during compressor operation. If 2nd stage cooling is satisfied and there is still a call for dehumidification, the reheat valve will once again be energized, as well as turning 2nd stage compressor back on. If there is a call for 2nd stage cooling, the reheat valve is de-energized, and the unit reverts to the cooling mode. If there is a call for 1st stage cooling while in the dehumidification mode, no action takes place. When the humidity control setpoint is satisfied, the valve is de-energized and both compressors are turned off. On a call for dehumidification, the reheat valve is energized and both compressors are turned on. This speed variation is only functional during the reheat mode. Once the reheat mode is terminated, or the temperature goes above 75 degrees, the condenser motor will revert back to high speed. For those applications, if the unit is in the reheat mode, and the outside air temperature is below 70 degrees, the motor changes to low speed. On certain units the use of a two speed condenser fan motor is required to maintain proper airflow. The three-minute minimum compressor on and off times are still active during compressor operation. zone sensor or thermostat while in reheat, the reheat valve is de-energized and the compressor continues to run. If there is a call for cooling from the space temperature controller, i.e. When the humidity control setpoint is satisfied, the valve is de-energized and the compressor is turned off. On a call for dehumidification, the reheat valve is energized and the compressor is turned on. Heating or 2nd stage cooling takes priority over dehumidification. Cooling takes priority over dehumidification on single compressor units. ĭehumidification takes priority over a single call for cooling on dual compressor units. A relative humidity sensor takes priority over a humidistat. In the absence of a zone humidity sensor input, an on/off input from a zone humidistat is used to initiate or terminate the dehumidification cycle. The economizer outside air damper is also driven to minimum position during dehumidification. If, during a dehumidification cycle, there is a call for heating, the dehumidification cycle is terminated. Dehumidification is not allowed if there is an active call for heating. Actuation of the reheat is accomplished by energizing a valve that allows refrigerant hot gas to flow through the hot gas reheat coil.ĭehumidification is allowed only when the outside air temperature is above 40F or below 100F. These connections are made through the low voltage terminal strip located in the unit control panel. Initiation of reheat is performed by an input to the RTOM module from either a relative humidity sensor or a humidi-stat type device. Dehumidification Sequence of Events for Voyager II and Precedent units.įactory installed hot gas reheat allows application of dehumidification.
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