Freezestat; Freezestat Alarm; Indoor Airflow Operation; Blower Speed Control - Bard FUSION-TEC HR36APA Service Instructions Manual

Freezestat

These units are equipped with a switch that monitors
the temperature of the refrigerant line leaving the
evaporator coil. To prevent the coil from freezing
and potentially allowing liquid refrigerant from the
evaporator to enter the compressor, the switch will open
when the temperature at this sensor is between 26.5°F
and 37.5°F and close again when the temperature is
between 49.5°F and 64.5°F.
This switch can be verified by:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
TECHNICIAN password 1313.
3. Press UP or DOWN keys to scroll to I/O Config;
press ENTER key.
4. Press UP or DOWN keys to scroll to Digital In
Config (C1); press ENTER key.
5. Reference 5 Freeze row and Val column (see Figure
21).
6. This value will display ON when the freezestat
has tripped and OFF when the freezestat is in its
normal position.
NOTE: This input is automatically configured by
the model number and cannot be enabled or
disabled on this screen.
FIGURE 21
Verifying Freeze Switch Status

Freezestat Alarm

When the freezestat digital input indicates a low
temperature event has occurred for longer than 120
seconds, the controller will generate a freezestat alarm.
This will then change the blower to high speed and
turn off the compressor for a minimum of 300 seconds.
The blower speed will return to normal once the alarm
condition has been removed. The compressor will start
again when the freezestat indicates no alarm and 300
seconds has passed. Once the condition is no longer
present, the alarm will automatically clear.
To adjust the freezestat alarm delay:
1. Press MENU key to go to the Main Menu screen.

Manual 2100-670B

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2. Press UP or DOWN keys and ENTER key to enter
USER password 2000.
3. Press UP or DOWN keys to scroll to System Config;
press ENTER key.
4. Press UP or DOWN keys to scroll to Alarm Setup
(A7); press ENTER key.
5. Press ENTER key to scroll to FreezeStat Alarm
Delay (see Figure 22).
6. Press UP or DOWN keys to change to the desired
value.
7. Press ENTER key to save the value.
FIGURE 22
Adjusting Freezestat Alarm Delay

Indoor Airflow Operation

Blower Speed Control

The blower is capable of changing speeds to best match
the requirements of the system depending on which
mode the system is in (see Table 3A or 3B on page 15).
The unit will automatically switch to the required
speed for each mode. High sensible mode and
dehumidification mode are both communicated
separately from the LV. For more information on the
high sensible command from LV, please see LV1000
Service Instructions 2100-673.

Additional Indoor Airflow Alarms

Supply Air Temperature Alarm

When the supply 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.

Condenser Fan

Condenser Fan Components

Condenser Fan
The unit is equipped with a condenser fan that is
driven by an electronically commutated motor (ECM).
This fan is controlled by a 0-10v signal provided from
the controller. The fan operates between 100-1200
rpm.