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Blower Status Alarm
If the blower is commanded on and the fan status
switch (differential pressure) has not indicated the fan
is running within 45 seconds, the system will generate
an alarm.
Disabling the blower status switch in I/O Config
disables this alarm.
This alarm is just a notification and will clear itself
when the conditions are no longer present.
To adjust the air flow alarm delay:
1. Press MENU key to go to the Main Menu screen.
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
(A8); press ENTER key.
5. Press ENTER key to scroll to Air Flow Alarm Del
(see Figure 32).
6. Press UP or DOWN keys to change to the desired
value.
7. Press ENTER key to save the value.
FIGURE 32
Adjusting Air Flow Alarm Delay
Filters
The unit is equipped with two (2) 20" x 30" x 2" MERV
8 filters. The filters slide into position making them easy
to service. The filters can be serviced from the outside
by removing either the right or left filter access panel.
Dirty Filter Switch
These units are equipped with a differential pressure
switch to indicate when the filter(s) needs to be
replaced (see Figure 30). The dirty filter switch
measures the pressure difference across the filter
through silicone tubing routed to the blower and vent
areas of the unit.
The switch circuit consists of a normally open filter
pressure switch. The switch will open when the
pressure differential goes above the setting indicated
Manual 2100-670I
Page
20 of 47
on the dial. When the pressure difference returns below
the setting on the dial, the switch will close.
Adjustment of dirty filter switch may be necessary to
ensure proper operation. See Table 7 and Figure 33 to
aid in setting the filter switch to operate at different
percentages of filter blockage.
Dirty Filter Alarm
The wall-mount unit is equipped with a differential
pressure switch input to the controller (see Figure 30).
When the switch indicates a dirty filter, the controller
will generate an alarm. Once the condition is no longer
present, the alarm will automatically clear. Additionally,
an indicator light will be turned on with the alarm and
turned off when the alarm clears.
Disabling the dirty filter switch in I/O Config disables
this alarm.
The threshold of this alarm is adjusted by changing the
settings on the switch (see Table 7).
Filter Indicator Light
These units are equipped with a 24v indicator light
mounted on side of unit that displays the current status
of the filter (as shown in Figure 33). When the light is
on, the filter needs to be replaced. Once the filter(s) has
been changed, the indicator light will turn off.
Freezestat
Earlier units were equipped with a switch that
monitored 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 freezestat
switch was designed to 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 was used in units running software
version 1.0.4 and earlier and has been removed.
The evaporator coil freeze protection alarm is now
calculated using system temperatures (see Evaporator
Freeze Condition Alarm on page 17).
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 19).
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.
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Troubleshooting
