Valent Controls IOM 64 IOM-C1-0616
Part Number 474626
3.4. Heating
A. The controller shall enable heating under the following condition.
a. Temperature control PID loop determines heating required due to the difference between the supply air
temperature and supply air temperature setpoint.
B. The controller shall perform the following functions in heating mode.
a. [Wheel, fixed speed] Enable at full speed before enabling mechanical heat.
b. [Wheel, modulating] When the unit modulates out of the economizer function (if equipped) toward the
heating mode, the energy recovery wheel shall modulate from 0-100% capacity before enabling
mechanical heat.
c. [Flat Plate] When the unit modulates out of the economizer function (if equipped), the bypass dampers
shall begin to modulate 0-100% full face before enabling mechanical heat.
d. Modulate capacity to maintain supply air temperature setpoint.
C. Defrost Mode
a. [Wheel, fixed speed] If the exhaust air temperature drops below 36°F, the energy recovery wheel shall be
disabled until the exhaust air temperature rises above 46°F.
b. [Wheel, modulating] If the exhaust air temperature drops below 36°F, the energy recovery wheel shall
modulate to maintain 36°F.
c. [Flat Plate] The bypass dampers shall modulate to maintain 38°F exhaust air temperature.
3.5. Cooling
A. The controller shall enable cooling under the following conditions.
a. Temperature control PID loop determines cooling required due to the difference between the supply air
temperature and supply air temperature setpoint.
B. The controller shall perform the following functions in cooling mode.
a. [Wheel, fixed speed] Enable at full speed before enabling mechanical cooling, if ambient temperature is
greater than space temperature by 5°F.
b. [Wheel, modulating] When the unit modulates out of the economizer function (if equipped) toward cooling
mode, the energy recovery wheel shall modulate from 0-100% capacity, if ambient temperature is greater
than space temperature by 5°F.
c. [Flat Plate] When the unit modulates out of the economizer function (if equipped) toward cooling mode, the
bypass dampers shall begin to modulate 0-100% full face, if ambient temperature is greater than space
temperature by 5°F.
d. Modulate capacity to maintain supply air temperature setpoint.
3.6. Economizer
A. The controller shall enter the economizer mode under the following conditions.
a. Temperature control PID loop determines cooling required due to the difference between the supply air
temperature and supply air temperature setpoint.
b. [Reference enthalpy] The outdoor air enthalpy is less than the outdoor air enthalpy reference setpoint.
c. [Comparative enthalpy] The outdoor air enthalpy is less than the space air enthalpy.
d. [Reference temperature] The outdoor air temperature is less than the outdoor air temperature reference
setpoint.
B. The controller shall perform the following functions in economizer mode.
a. [Wheel, fixed speed] Energy recovery wheel shall jog based on a user-defined duty cycle.
b. [Wheel, modulating] The energy recovery wheel shall operate based upon user-selectable configuration.
1. [Off When Economizing] Disable energy recovery wheel rotation.
2. [On When Economizing] Energy recovery wheel shall rotate at a user-defined speed.
3. [Always On] Energy recovery shall always rotate at a user-defined speed.
c. [Flat Plate] Open heat exchanger bypass damper.
d. Modulate the outdoor air damper and return air damper positions to maintain the supply air temperature
setpoint.
4. DEHUMIDIFICATION
4.1. The controller shall enable the dehumidification control sequence when either of the following conditions is met.
A. [Supply air control] Outdoor dewpoint is greater than the outdoor air dewpoint setpoint AND the outdoor air
temperature is greater than the supply air temperature setpoint.
B. [Space temperature and humidity control with supply air reset] Outdoor dewpoint is greater than the outdoor air
dewpoint setpoint AND the outdoor air temperature is greater than the supply air temperature setpoint OR the
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