Reznor ZQYRA Unit Installation Manual - Manual (Page 29)

Form I-ZQYRA P/N 260414R5, Page 29
Energy Recovery Wheel
Control
Upon proof of the supply air and exhaust air fans, the controller will start the energy
recovery wheel. The unit controller will monitor the wheel discharge air temperature
and humidity and will calculate the leaving air dewpoint.
Heat Pump Control The heat pump is controlled to maintain the discharge air temperature. When the heat
pump is in a defrost state, electric heat coils (5kW on Size 8; 10kW on Size 10) are
activated to ensure the discharge air stays at a comfortable temperature.
There are four pre-configured types of control for the heat pump. Dewpoint control
(default); Dewpoint with heating/cooling setpoint with outside air changeover (heating/
cooling setpoints only used when dewpoint is below setpoint); Dewpoint with heating/
cooling setpoint with space temperature changeover (heating/cooling setpoints only
used when dewpoint is below setpoint); and Dewpoint with outside air temperature
reset (reset setpoints only used when dewpoint is below setpoint). The heat pump
control configuration can be found from the main menu under Service Menu/
Config/Edit Equipment Config. The setpoint to adjust is called Temp Cntrl and the
selectable options are Dp (Dewpoint), HtgClgOa (heating/cooling setpoint with
outside air changeover), HtgClgSpc (heating/cooling setpoint with space temperature
changeover), and OAReset (outside air temperature reset). The following sequence
defines each control type.
Heat Pump Control Using Dewpoint Only (Default Configuration) - Upon proof of
the supply and exhaust air fans, the unit controller shall monitor the wheel leaving air
dewpoint.
•
If the dewpoint is above the Dewpoint Changeover Setpoint ( DpCngOvrLt =
59°F/15°C), the unit will enable the heat pump and modulate the system to
maintain a unit leaving discharge temperature high dewpoint setpoint (DatSpHiDp
= 58°F/14°C).
•
If the dewpoint is below the Dewpoint Changeover Setpoint ( DpCngOvrLt =
59°F/15°C), the unit will enable the heat pump and modulate the system to
maintain a unit leaving discharge temperature low dewpoint setpoint (DatSpLoDp
= 70°F/21°C).
Heat Pump Control Using Dewpoint with Heat/Cool Setpoints with Outside Air
Changeover - Upon proof of the supply and exhaust air fans, the unit controller shall
monitor the wheel leaving air dewpoint.
•
If the dewpoint is above the Dewpoint Changeover Setpoint ( DpCngOvrLt =
59°F/15°C), the unit will enable the heat pump and modulate the system to
maintain a unit leaving discharge temperature high dewpoint setpoint ( DatSpHiDp
= 58°F/14°C).
•
If the dewpoint is below the Dewpoint Changeover Setpoint ( DpCngOvrLt =
59°F/15°C), the unit will enable the heat pump and modulate the system to
maintain a unit leaving discharge temperature low dewpoint heating and cooling
setpoint based on the OA conditions.
o Once the OA temperature is above the outside air changeover setpoint
( OaCngOvr = 65°F/18.3°C), the unit will maintain the leaving discharge
temperature cooling setpoint low dewpoint ( DatClgSpLoDp = 60°F/15.5°C).
space when the unit is in the occupied condition. This configuration also allows the unit
to monitor the CO
2
or VOC level and override the unit “on” when the level is above the
setpoint. Setting the sensor control setpoint to monitor will allow you to just monitor the
VOC or CO
2
levels but the unit will not react to the levels.
Required Setpoint Settings: Sch Cmd - On/Off
Occupancy - Type 8
CN Option - CN5
Schedule - [Local] or BAS
DI Override - [Off] or On
Sensor - [CO
2
] or VOC
CO
2
or VOC Level - Current Reading
CO
2
or VOC Setpoints - [800] / 60
CO
2
or VOC Off Diff - [50] / 15
Minimum Run Time - [5 minutes]
Alarm - [ Enable] or Disable