Dehumidification - Greenheck DOAS v8.1 Reference Manual

Control Variables

Dehumidification

Menu
Outside Enthalpy & Dry Bulb - Economizing is allowed when outside enthalpy
is less than the enthalpy set point (23btu/lb) and the outside temperature is less
than the temperature set point (65°F).
Comparative Dry Bulb - Economizing is allowed when outside temperature is
less than the space or return temperature.
Comparative Enthalpy - Economizing is allowed when outside enthalpy is less
than the space or return enthalpy.
e s
conomizer eTTings
There is a built-in hysteresis that disables economizer above the economizer
setpoint.
(Example: If economizer outside dry bulb = 65°F, economizer operation is
disabled above 67°F).
e r o
nergy educTion nly
If enabled, the OA damper and recirculation damper will not modulate during
economizer. Instead, only the energy recovery device will modulate to ensure no
energy is transferred from the supply airstream and exhaust airstream.
The Dehumidification menu allows the user to view and adjust dehumidification
control parameters.
d m
ehumidiFicaTion ode
Possible Modes:
• Outside Air Temp is greater than cold coil setpoint plus offset (10ºF)
• Inside RH*
• Inside dew point*
• Outside dew point
• Inside RH or inside dew point*
• Inside RH or inside dew point or outside dew point
• Inside RH and inside dew point*
• Inside RH and inside dew point or outside dew point
*Available during unoccupied mode.
There must be a constant call for dehumidification for the duration of the enable
delay for dehumidification mode to become enabled. The call remains active until
conditions are satisfied and dehumidification mode has been active for the min
active time. Reference Ctrl Variables/Advanced/Unit Config/Unit Configuration
Occupied Dehum Call for dehumidification method options.
d m
ehumidiFicaTion ode
If the unit is unoccupied while there is a dehumidification call, the unit will start
and dehumidify until the unoccupied dehumidification setpoints are satisfied.
The above dehumidification modes marked with an * indicate availability during
unoccupied mode. The unoccupied dehumidification mode can be set differently
than the occupied dehumidification mode. Reference Ctrl Variables/Advanced/
Unit Config/Unit Configuration Unoccupied Dehum Call for dehumidification
method options.
c
onTrol
- o
ccupied
- u
noccupied
Microprocessor Controller for DOAS 21