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OPERATION
Fan Sequence Operations (ISU 347, 348, 349)
If heat pump or conventional application modes are enabled in
ISU 170, then ISU 347 is not available for fan ramp algorithm.
The fan operates as a default ON/AUTO selection that works
the same way as our CommercialPRO TB7220 thermostat.
There is only one fan relay output that is activated.
If PTAC or fan coil thermostat application modes are enabled in
ISU 170, then ISU 347 fan ramp algorithm is available for
installer setup selection. The fan ramp algorithm will
automatically calculate the appropriate fan speed that is
needed to meet the proportional band requirements to speed
up setpoint satisfaction. When the setpoint is satisfied it will
revert to the lowest fan speed setting to conserve energy.
The thermostat comes factory default with the fan ramping
algorithm enabled (ISU 347). This gives the user the ability to
select Auto-Lo-Med-Hi option in ISU 348 or Auto only option in
ISU 348. Auto sets the thermostat into the fan ramping
algorithm mode and automatically sets the sufficient speed for
PI control. Auto also automatically shuts the fan off when there
is not a call for heating or cooling. If the user decides to disable
ISU 347, then the fan will only have Lo-Med-Hi option
available.
If ISU 347 is not enabled, then ISU 348 does not appear as a
user selection choice.
If ISU 347 is enabled, then ISU 349 is available as a selection
choice. The user can select either a 2 hour or 4 hour timer fan
reset function. The fan will reset from a constant on speed to
Auto mode after the time period expires. If ISU 347 is not
enabled, then ISU 349 does not appear as a user selection
choice.
Equipment Sequence Operations (ISU 170)
Heat Pump and Conventional
Heat Pump and conventional use a single fan speed. The
single fan speed label is the G terminal relay output. Display on
the thermostat for these modes will give the Fan On/Auto
option. There is no fan ramping algorithm, ISU 347, 348, 349
are not available.
PTAC
PTAC modes 10 and 11 will have the same selection options
available as the heat pump selection options. The only
difference is that the PTAC options have a Lo and Hi speed fan
output instead of single speed output and that it follows the fan
sequencing described above with ISU 347, 348, 349.
4 Pipe
4 pipe is treated similar to 1H/1C conventional. It follows the
fan sequencing described above with ISU 347, 348, 349.
2 Pipe
There are two different 2 pipe modes - 2 pipe only and 2 pipe
with reheat.
2 pipe only - 2 pipe modes do not contain the ability to have
automatic changeover. They are manual changeover only. The
thermostat will have a priority when choosing a system mode
(heat or cool). When ISU #340 has a 2 pipe changeover
TB7100A1000 MULTIPRO™ MULTISPEED AND MULTIPURPOSE THERMOSTAT
sensor enabled, the thermostat screen system mode will lock
on heat or cool (whatever the changeover sensor is
communicating to the thermostat). If ISU #340 does not have a
changeover sensor enabled, then the system mode from the
thermostat screen can manually be adjusted between heat or
cool. It follows the fan sequencing described above with ISU
347, 348, 349.
2 pipe with reheat - 2 pipe modes do not contain the ability to
have automatic changeover. They are manual changeover
only. The thermostat will have a priority when choosing a
system mode (heat or cool). When ISU #340 has a 2 pipe
changeover sensor enabled, the thermostat screen system
mode will lock on heat only. When the 2 pipe changeover
sensor is sensing cool mode, the user can adjust to heating
mode which will bring on the auxiliary heat. If ISU #340 does
not have a changeover sensor enabled, then the system mode
from the thermostat screen can manually be adjusted between
heat or cool. It follows the fan sequencing described above
with ISU 347, 348, 349.
Operating Sequence
The thermostat energizes specific terminal(s), depending on
the demand for heating, cooling or fan. The thermostat screen
shows the time, inside temperature, system and fan selections.
Additional indicators are shown when the heating, cooling or
fan is energized. See Tables 8 and 9 for specification
information.
Table 8. Sequence of Operation for Conventional Systems.
System
Setting
Off
Cool
Cool
or Auto
Heat
Heat
or Auto
a
If Installer Setup System type is set to two stages of cooling.
b
G energizes only if Installer Setup 0180 is set to Electric.
Table 9. Sequence of Operation for Heat Pump Systems.
System
Setting
Off
Cool
Cool
or Auto
Heat
Heat
or Auto
a
Configure O/B in Installer Setup. Based on last piece of
equipment called (cooling = O; heating = B).
b
If Installer Setup System Type is set to 2Heat/1Cool Heat
Pump with Auxiliary Heat.
17
Fan
Setting Call for Action
Auto
—
Auto
—
Auto
Stage 1
Cooling
Auto
—
Auto
Stage 1
Heating
Fan
Setting Call for Action
Auto
—
Auto
Stage 1 Cooling
Auto
—
Auto
Stage 1 Heating
Stages 1 and 2
Heating
Energize
Screen
Terminals
Message
—
—
—
—
Y, G
Cool On
—
—
b
Heat On
W, G
Energize
Screen
Terminals
Message
—
a
O/B
Cool On
a
Y, G, O/B
a
—
O/B
Heat On
a
Y, G, O/B
Auxiliary
b
Y, W1
, G,
Heat On
a
O/B
63-2675—01
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