Specifications

To troubleshoot the error, check the operation of the sys-
tem heating and cooling equipment.
1. Check the economizer operation. The economizer could
be allowing more outside air into the system than the equip-
ment was designed to use.
2. The HVAC equipment has internal controls that can au-
tomatically shutdown the heating or cooling capacity based
on operating limits. When this occurs, the monitor ther-
mostat relay pack remains energized, but the equipment
cannot provide conditioned air to the zones.
3. Check the capacity of the HVAC equipment to handle the
building load. If the equipment is undersized, it may not
be able to provide supply air that is either warm enough
or cold enough to meet the system need during design
conditions.
4. Reset the monitor thermostat.
Heating Mode Error Set Point — The Heating Mode Error
Set Point establishes the supply-air temperature during a sys-
tem heating mode. To configure the option, set category 7,
option 9. Use the left set point button to raise or lower the
temperature until the desired set point value is shown. The
range of acceptable values is 0 to 140 F in 5° F increments.
The default is 0° F.
System Cooling Mode Set Point — The System Cooling Mode
Set Point establishes the supply-air temperature during a sys-
tem cooling mode. To configure the option, set category 7,
option 10. Use the left set point button to raise or lower the
temperature until the desired set point value is shown. The
range of acceptable values is 0 to 140 F in 5° F increments.
The default is 140 F.
DIRTY FILTER ERROR (SE09) — The Dirty Filter Error
will occur when the filter status switch sends an ON (dirty)
signal to the monitor thermostat. The filter status switch com-
pares the pressure on both sides of the filter. If the pressure
difference rises above the factory-defined set point, an SE09
error will occur.
To clear a system error, use the Unit Reset function. The
Unit Reset function is in category 7, option 11. The default
is OFF. Use the left set point buttons to set the option to ON.
The monitor thermostat will reset all errors.
To troubleshoot the error, clean the filter and check the
operation of the system fan. Check the positioning of the
filter sensor tubes. They should be unobstructed and in the
correct location. Refer to the fan/filter status installation in-
structions for more information.
INDOOR AIR QUALITY ERROR (SE10) — When the CO
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level exceeds the preset level, the sensor signals the monitor
thermostat. The monitor thermostat will wait until the IAQ
Alarm Delay option (category 14, option 8) has expired, then
it will issue an SE10. The system (if configured) will bring
in fresh outdoor air to meet IAQ requirements. If the IAQ
Alarm Delay is not set to give the system enough time to
correct IAQ problems, the SE10 will be issued every time
the IAQ mode is entered.
If the lockouts prevent IAQ mode from operating, the sys-
tem will not enter IAQ mode. These lockouts are user-
configured and measure outdoor humidity (category 14,
option 5), and outdoor temperature (category 14, options 6
and 7).
To clear a system error, use the Unit Reset function. The
Unit Reset function is in category 7, option 11. The default
is OFF. Use the left set point buttons to set the option to ON.
The monitor thermostat will reset all errors.
HIGH/LOW TEMPERATURE LIMIT EXCEEDED (SE11)
Heating Mode — An alarm is issued when any supply air
sensor in the system is above the first or second stage
heating temperature limit (depending on which stages are
active).
Cooling Mode — An alarm is issued when any supply air
sensor in the system is below the first or second stage
cooling temperature limit (depending on which stages are
active).
Refer to the System Time Guards section on page 28 for
information on setting the temperature limits.
Heat/Cool Mode Alarms are cleared from the system in
two ways:
• Cycle power to the thermostat OFF, then ON.
• Reset the Unit Thermostat. Initiate a reset by switching
the Unit Reset to the ON (Category 7, Option 11).
CANNOT DETECTINDOOR FAN OFF (SE12) — The moni-
tor thermostat will declare an SE12 if the FAN relay is deen-
ergized, but the fan status switch is sending an ON status.
To clear a system error, use the Unit Reset function. The
Unit Reset function is in category 7, option 11. The default
is OFF. Use the left set point buttons to set the option to ON.
The monitor thermostat will reset all errors.
To troubleshoot the error, check the operation and wiring
of the system fan.
STUCK GAS VALVE (SE13) — The Stuck Gas Valve se-
quence is used to allow the system to properly react to a
failure mode of the HVAC unit when the gas valve becomes
stuck in the open position. When this condition exists, the
unit is unable to shut off the heat. To minimize this problem,
the internal limit switch trips causing the indoor fan to turn
on and remain on until the gas is manually shut off and the
heat exchanger cools to normal temperatures.
Without this feature, a VVTt system operating normally
would close each of its zone dampers as space conditions
warmed to set point. This causes the heated air to be recir-
culated back through the unit, further aggravating the over-
heating problem. With the Stuck Gas Valve sequence, the
VVT dampers open to their configured Maximum Damper
Position (category 3, option 1). This allows space tempera-
tures in the building to rise to higher than normal tempera-
ture levels. However, this sequence reduces the temperature
buildup in the unit and keeps the heat exchanger operating
within temperatures to prevent failure.
During No System Mode — If the duct temperature rises to
greater than 175 F, the indoor fan is started. The fan will
remain on if that temperature does not drop below 150 F
after 3 minutes. The bypass damper will be closed, and all
zone dampers will open to their maximum position. A Stuck
Gas Valve alarm (SE13) will be initiated.
During a Cooling Mode — If the duct temperature does not
drop below 100 F within 10 minutes, the cooling mode will
be dropped for 10 minutes. The "No system Mode" logic
will test for this condition.
During a Heating Mode — No action is required in this mode.
The alarm can be cleared or erased from the system in
two ways:
• Cycle power to the thermostat off, then on.
• Initiate a reset by switching the Unit Reset option to the
ON configuration (category 7, option 11).
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