Fan Modes; Application Modes - Honeywell SuitePRO TB8575 Installation Instructions Manual

TB6575/TB8575 SUITEPRO™ DIGITAL FAN COIL THERMOSTATS
For Cool Mode, when Economy Setback is enabled, the
set point changes to the remote setback cooling setpoint
(IS CODE #21).
For 4 pipe applications with Auto Changeover and Heat/
Cool Setpoints, when Economy Setback is enabled, the
cool setpoint changes to the remote setback cooling
setpoint and the heat setpoint changes to the remote
setback heating setpoint. The new effective deadband is
the difference between the remote setback heating
setpoint and the remote setback cooling setpoint.
Fig. 26 illustrates the relationship between setpoints,
Remote Setback, and deadband for auto changeover with
heat and cool setpoints.
UNOCCUPIED DEADBAND
DEADBAND
UNOCCUPIED DEADBAND
Fig. 26. Auto Changeover with Heat/Cool Setpoints
deadband illustration.
For 4 pipe applications with Auto Changeover and a single
setpoint, when Economy Setback is enabled, the setpoint
will revert to a dual heat/cool setpoint approach. The
remote setback heating and remote setback cooling
setpoints will be used to create an effective unoccupied
deadband.
Fig. 27 illustrates the unoccupied deadband when
Economy Setback is enabled for 4-pipe single setpoint
auto changeover.
UNOCCUPIED DEADBAND
UNOCCUPIED DEADBAND
Fig. 27. 4 Pipe Auto Changeover with Single Setpoint
and Economy Setback Deadband Illustration

Fan Modes

VERSASPEED™ FAN RAMPING
When the fan switch is in auto, the thermostat will cycle
the fan using the fan ramping algorithm. The appropriate
fan speed is selected according to Fig. 28.
62-0278—13
REMOTE SETBACK COOL SETPOINT
COOL SETPOINT
HEAT SETPOINT
REMOTE SETBACK HEAT SETPOINT
M27562
REMOTE SETBACK COOL SETPOINT
COOL SWITCHING POINT
SETPOINT
HEAT SWITCHING POINT
REMOTE SETBACK HEAT SETPOINT
M31331
The fan ramping algorithm is illustrated in Fig. 28
+4°F
DIFFERENCE
+2°F
BETWEEN
RT AND
SETPOINT
-2°F
-4°F
Fig. 28. VersaSpeed™ fan ramping algorithm
AUTO FAN RESET (IS CODE #24)
If Auto Fan Reset is enabled, and a constant fan speed is
selected, the thermostat resets the fan to Auto.
• Value = 1: The fan resets back to Auto after 2 hours.
• Value = 2: The fan resets back to Auto after 4 hours.
The start time is calculated after the initial call for Heat/
Cool is satisfied. Then, the two or four hour timing begins.
The fan is set back to Auto when the 2-hour or 4-hour
delay expires.

Application Modes

2 PIPE SEASONAL CHANGEOVER APPLICATIONS
These applications require the pipe sensor as a N.O,
N.C., or Analog Input to detect seasonal changeover:
• 2 pipes with auto changeover
• 2 pipes with auxiliary heat
Changeover occurs when the system has been changed
over from the boiler to the chiller. This occurs on a
seasonal basis from winter to summer months. When
using a pipe sensor as an analog input, the thermostat
can use the logic below to determine what mode to
operate in. A changeover will occur when the pipe
temperature goes above the threshold for heating or
below the threshold for cooling. If a purge has not
occurred or a call has not been satisfied in awhile, the
pipe temperature may start to get close to the ambient
temperature. In this case, the thermostat will only
changeover once the temperature falls into the opposite
threshold.
2 Pipes with Auto Changeover
For this application the system switch only provides "Off"
and "Auto". When in "Auto" mode the water temperature
will indicate if the thermostat should operate in heating or
cooling.
Operation:
After exiting the installer setup, the thermostat will perform
a 5 minute purge. During this initial 5 minute purge, the
valve (W/Y) will energize and the fan will be de-energized.
After the 5 minute purge, the thermostat will go into the
appropriate mode as described in Table 6.
16
FAN SPEED IS HIGH
FAN SPEED IS MEDIUM
COOL
FAN SPEED IS LOW
SETPOINT
FAN SPEED IS LOW
FAN SPEED IS MEDIUM
FAN SPEED IS HIGH
HEAT
illustration.
M27563