Return Air Temperature Alarm; Temperature/Humidity Control Operation; Cooling Sequence: Economizer Available; Economizer Operation In Orphan Mode - Bard FUSION-TEC WR35BPA Service Instructions Manual

8. The update will not take effect until the cursor is
moved out of the Offset parameter.
9. Once adjusted, press the ESCAPE key several
times to return to Main Menu screen.

Return Air Temperature Alarm

When the return air temperature sensor value is out of
range (-41.0 to 303.0°F), the controller will generate
a sensor failure alarm to indicate the sensor is not
working properly.
This alarm is fixed and cannot be adjusted.

Temperature/Humidity Control Operation

When the unit is connected to the LC controller, it
will receive all of its heating, cooling and ventilation
commands from the controller. When the unit is in
orphan mode, it will heat, cool and ventilate based on
the return air temperature measurement. The return air
temperature will be compared to the cooling setpoint.
Based on differentials above and below the setpoint,
the available cooling and heating stages will be utilized.
To change or view the unit setpoint:
1. From the Status screen, press UP or DOWN key
until Quick Menu displays Setpoints icon (
Press ENTER key.
Free Cooling Free Cooling
Available Not Available
Mechanical
Free Cooling
Cooling Stage 1
Mechanical Mechanical
Cooling Stage 1 Cooling Stage 2
Mechanical
Not Used
Cooling Stage 2
Heat Stage 1
NOTE: Deadband refers to a region where one end limit will turn the heating or cooling function on and the opposite end
limit will turn the heating or cooling function off.
Manual 2100-695C
Page 14 of 56
).
FIGURE 20
Staging
72°F 73°F 74°F 75°F
Off
55°F 56°F 57°F 58°F
Off
2. Press ENTER key to scroll to Cool Setpoint or Heat
Setpoint (see Figure 4 on page 8).
3. Press UP or DOWN keys to change the value to
desired heating and/or cooling setpoint.
Cooling Sequence – Economizer Available
NOTE: This description is based on the example shown
in Figure 20 and Figure 23 (page 16).
If the return air temperature is higher than 79°F
(Setpoint of 77°F + Stage 1 On Differential of 2°F) and
outdoor conditions are acceptable for economizing, the
unit will enable economizer operation (free cooling).
If the return air temperature is higher than 80°F
(Setpoint of 77°F + Stage 2 On Differential of 3°F),
the unit will enable mechanical cooling stage 1. If the
return air temperature is higher than 81°F (Setpoint
of 77°F + Stage 3 On Differential of 4°F), the unit
will enable mechanical cooling stage 2. Each stage
will then be disabled when the return air temperature
reaches the setpoint plus the stage off differential.

Economizer Operation in Orphan Mode

In orphan mode,there is a chance that the economizer
will not be given ample time to operate before the
heat load requires more cooling. In this case, there is
a delay that can be enabled in order to allow for the
most amount of free cooling to be utilized before the
compressor is staged on.
Setpoint
76°F 77°F 78°F 79°F
Deadband On
Setpoint
59°F 60°F 61°F 62°F
Deadband On
80°F 81°F 82°F 83°F
63°F 64°F 65°F 66°F