Page 80
19.1.4.5. Heating Demand (General Operation)
The M3 Unit Controller directly monitors space temperature through the room sensor. Based on this information, the M3 Unit
Controller turns on or off the heating stages to maintain the desired temperature set point. Increasing heating stages
provides additional heating capacity while decreasing heating stages provides less heating capacity. The M3 Unit Controller
has direct control over rooftop unit mechanical heating staging operation. Some units feature four separate heating stages
that can provide up to four stages of mechanical heating operation. The specific heating capacity varies for each stage
depending on the heat source. Depending on the room sensor configuration setting, occupants in the space can change the
set point. The M3 Unit Controller automatically recognizes this change and instructs the unit to respond accordingly.
19.1.4.6. Heating Demand (Electric)
Energence units feature multiple electric heat sections available in sizes from 7.5 kW to 180 kW (depending on unit size and
voltage). Units can provide up to four stages of mechanical heating depending on the size of the electric heater. Staged
operation occurs similar to cooling operation, with the M3 Unit Controller activating or deactivating sections of the electric
heater as the demand for heat increases or decreases.
19.1.4.7. Humiditrol Dehumidification Operation - Dehumidification Demand
Upon a dehumidification only demand, the M3 Unit Controller activates various compressors depending on model for
reheating. At the same time, the M3 Unit Controller will use the solenoid valve(s) to divert hot gas from the compressor(s) to
the reheat coil.
The cooled and dehumidified air from the evaporator is then reheated as it passes through the reheat coil. The
de-superheated and partially condensed refrigerant continues to the outdoor condenser coil where condensing is
completed. The reheat coil is sized to offset most of the first and second stages of sensible cooling effect during reheat
only operation. This reduction in sensible cooling capacity extends compressor run time to control humidity when cooling
loads are light. The unit continues to operate in this mode until the dehumidification demand is satisfied. A heating demand
terminates reheat operation. The M3 Unit Controller relative humidity set point is set at the factory for 60% and can be
adjusted at the M3 Unit Controller or with the L Connection Network Unit Controller Software. For Network Control Panel
(Network Control Panel) applications, the humidity set point can be adjusted at the Network Control Panel. The M3 Unit
Controller also has an option for an external digital input for the dehumidification demand. This demand must be provided
from an external third-party controller.
For unit model specific details, refer to the unit installation instruction.
19.1.4.8. Humiditrol Dehumidification Operation - Cooling Demand Only
The unit will operate conventionally whenever there is a demand for cooling and no dehumidification demand. The unit can
provide up to four stages of mechanical cooling in this scenario. Free cooling is only permitted when an economizer is
present, there is no demand for dehumidification and the outdoor air is suitable for this function.
19.1.4.9. Humiditrol Dehumidification Operation - Cooling and Dehumidification Demand
Stage one cooling and dehumidification demand: The system activates various number of compressors depending on
model plus reheat. This provides approximately 75% humidity removal capacity plus 25% cooling capacity.
Stage two cooling and dehumidification demand: The system activates all compressors plus reheat. This provides
100% humidity removal capacity plus approximately 50% cooling capacity.
Stage three cooling and dehumidification demand: The system activates all compressors. If there is a fourth
compressor, it along with the reheat coil will cease operation. This provides approximately 75% of humidity removal
capacity and 75% cooling capacity.
Stage four cooling and dehumidification demand: The system activates all compressors. This will provide 100%
humidity removal capacity and 100% cooling capacity.
For unit model specific details, refer to the unit installation instruction.
To Next Page
Loading...
Need help?
General
