Honeywell TB8575 Thermostat User Manual

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TB6575/TB8575 Digital Fan Coil  
Thermostats  
INSTALLATION INSTRUCTIONS  
Valves and auxiliary electric heaters can be controlled  
using a relay or contactor controlled by the system  
switch.  
FEATURES  
•
•
Simple, intuitive user interface.  
Pre-installed lead wires for fast installation  
(TB6575A, TB6575B and TB6575C models only)  
•
•
Backlight display permits easy viewing in any  
light.  
Four buttons allow manual control of system  
operation, fan speed, and temperature setpoint  
adjustment.  
•
Digital display of ambient temperature, setpoint,  
heating or cooling mode, fan status, and remote  
setback  
PRODUCT DESCRIPTION  
The TB6575 and TB8575 are a family of Digital Fan Coil  
thermostats for residential and commercial applications  
such as hotels, condominiums, school classrooms, etc.  
•
•
•
•
Proportional plus Integral (P+I) control algorithm  
for precision temperature regulation.  
Four models are available for your application:  
Single Setpoint and Heat/Cool setpoint methods  
for 4-pipe auto changeover.  
•
TB6575A1016 – 2-pipe or 4-pipe with seasonal/  
manual/automatic heat/cool changeover; 120/240  
Vac.  
Adjustable maximum heating and minimum  
cooling setpoint limits using range stops.  
•
•
TB6575B1000 – 2-pipe only with seasonal or manual  
heat/cool changeover; 120/240 Vac.  
TB6575C1016 – 2-pipe or 4-pipe with seasonal/  
manual/automatic heat/cool changeover; 120/240/  
EEPROM permanently retains user settings,  
including setpoints, during power loss (no  
batteries required).  
2
77 Vac.  
•
•
•
Selectable °C or °F display via Setup button on  
thermostat.  
•
TB8575A1016 – 2-pipe or 4-pipe with seasonal heat/  
cool changeover; 24Vac.  
Displayable pipe sensor temperature readout to  
aid in troubleshooting.  
All four models are suitable for multiple applications.  
Changes in output wiring and external links between  
wiring terminals allow you to configure the thermostat for  
the appropriate application.  
Selectable to allow the fan motor to always begin  
on high speed to ensure sufficient torque at  
startup.  
The applications that are available are:  
•
•
•
•
Option to wire a remote indoor temperature  
sensor.  
•
•
•
Heating or Cooling only  
Two pipes: Heat or Cool with Manual Changeover  
Two pipes: Heat or Cool with Seasonal Changeover  
Freeze protect algorithm turns on heat when  
needed.  
(requires optional pipe sensor)  
Economy Setback options via dry contact or  
Activity Sensing  
•
Two pipes: Heat or Cool with Auxiliary Heat and  
Manual or Seasonal Changeover (requires optional  
pipe sensor)  
Advanced fan control with VersaSpeed™ fan ramp  
algorithm and Auto Fan Reset  
•
•
•
Four pipes: Mixed Manual and Auto Changeover  
Four pipes: Manual Changeover  
Four pipes: Auto Changeover  
The fan is controlled from the thermostat. The Low,  
Medium, High, or Auto fan settings are easily made with  
a press of a key.  
6
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Enclosure: Plastic (cover, sub-base, and optional adap-  
SPECIFICATIONS  
tor plate)  
Supply Voltages:  
Junction Box Mounting: Direct mounting on a horizontal  
single gang NEMA 2 x 4 in. surface mount electrical box,  
or on 4 x 4 in. box or vertical 2 x 4 in. surface mount  
electrical box with the optional 50033847-001 adapter  
plate.  
TB6575A1016 and TB6575B1000:  
•
•
120 Vac ±10% at 50/60Hz  
240 Vac -15% to +10% at 50/60Hz  
TB6575C1016:  
•
•
•
120 Vac ±10% at 50/60Hz  
240 Vac -15% to +10% at 50/60Hz  
277 Vac ±10% at 50/60Hz  
Dimensions: See Fig. 1 on page 3.  
TB8575A1016:  
•
Wiring: 11 screw-in terminals located on the sub-base  
capable of accepting up to 2 x 18 AWG (0.8 sq. mm), 1 x  
20 to 30 Vac at 50/60Hz (using 24 Vac, Class 2,  
NEMA rated transformer)  
1
6 AWG (1.3 sq. mm), or 1 x 14 AWG (2.1 sq. mm) wires.  
Safety Fuse: 15 A, 350V. If the safety fuse blows, the  
thermostat must be replaced. The fuse is not field  
replaceable.  
Accepts stranded or unstranded 14-28 gauge wire.  
NOTES:  
1
. The TB6575A1016 and TB6575C1016 models  
are pre-fitted with color-coded fly leads (16  
AWG) attached to seven terminals.  
Electrical Ratings: (see Table 1).  
Table 1. Electrical Ratings.  
Amps (inductive) for:  
2. The TB6575B1000 model is pre-fitted with color-  
coded fly leads (16 AWG) attached to six  
terminals.  
Component  
24 Vac 120 Vac 240 Vac 277 Vac  
3. The TB8575A1016 model does not have fly  
leads attached to any terminals.  
Fan Relay  
1.0 A  
6.0 A  
1.0 A  
3.0 A  
1.0 A  
2.4 A  
1.0 A  
4
. See Table 3 on page 5 for fly lead usage.  
Heat/Cool Relay 1.0 A  
Minimum Operational Life (at maximum load):  
Thermostat contacts: 100,000 cycles  
Environmental Ratings:  
Temperature:  
Approvals:  
Operating Range: 18°C to 49°C (0°F to 120°F).  
Shipping and Storage Range: -29°C to 49°C (-20°F to  
20°F).  
CSA Certified C/US for Canada and the U.S.A. Meets  
the same requirements as UL-873 and UL 1/4 HP.  
FCC Part 15 Class B  
1
Humidity: 5% to 90% RH, non-condensing.  
Accessories:  
Onboard Temperature Sensor:  
Type: 10K NTC  
Working Range: 18°C to 49°C (0°F to 120°F)  
Display Range: 0°C to 37°C (32°F to 99°F)  
Accuracy ±2.0°F at 70°F  
•
50033847-001 – Adapter plate for mounting on a  
vertical 2 x 4 in. single-gang or double-gang NEMA  
standard vertical switch box (6 1/4 in. (158 mm) x 5 1/  
16 in. (128 mm) x 13/22 in. (10 mm)).  
•
TR21 – 20K Ohm NTC Non-Linear Remote  
temperature sensor.  
Other acceptable remote temperature sensors are —  
Remote Temperature Sensor (optional):  
Type: 20K NTC  
Working Range: 18°C to 49°C (0°F to 120°F)  
Display Range: 0°C to 37°C (32°F to 99°F)  
Accuracy ±2.0°F at 70°F  
•
20K Ohm: C7041B2005, C7041B2013,  
C7041C2003, C7041P2004, C7770A1006,  
C7772A1004, and C7772A1012  
•
10K Ohm (for averaging only): TR21-A  
Remote Pipe Sensor (optional):  
Type: 20K NTC  
Working Range: 0°C to 93°C (32°F to 199°F)  
Display Range: 0°C to 93°C (32°F to 199°F)  
Accuracy ±5.0°F over the temperature sensing range  
•
PS20 (535-34AB08-203) – Remote pipe sensor  
(
20K Ohm)  
•
•
W6380B1005 – Fan Coil Unit Relay Control Center  
WSK-24 - Wireless Occupancy Solution (Receiver,  
occupancy sensor and door sensor)  
Remote Setback Input: Dry contact, maximum  
Models, applications, and features:  
Table 2 identifies the applications and features of each  
model.  
resistance of 100 ohms. TB6575 – 9Vdc, < 4 mA; TB8575  
–
16 Vdc, < 5 mA. Note Electrical WARNING on page 3.  
Remote Setback Range:  
Heating: 10°C to 21°C (50°F to 70°F).  
Cooling: 22°C to 32°C (72°F to 90°F).  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Table 2. Applications and Features  
Applications  
Features  
Heat/Cool/ Pipes Voltage Number  
Energy Fan: On, Manual/  
a Savings Auto, or 3 Auto  
Remote Back  
Sensor Light  
Pipe  
Sensor  
Auto  
b
of Relays  
Models  
Input  
speed  
Changeover  
TB6575A1016 All  
2 or 4 120 or  
40 Vac  
5
4
5
2
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
TB6575B1000 Heat or  
Cool  
2
120 or  
240 Vac  
TB6575C1016 All  
2 or 4 120, 240  
or 277  
Vac  
TB8575A1016 All  
2 or 4 24 Vac  
5
a
b
The five relays are wired via terminals W, Y, Gh, Gm, and Gl. Relay 1 controls Heat open (W) or Cool open (Y). Relay  
controls Cool open or Electrical heater output (Y/A). Relays 3, 4, and 5 control the High, Medium, and Low fan  
speeds respectively (Gh, Gm, and Gl).  
NOTE: In 2-pipe configurations without Auxiliary Heat, only 4 relays are used; relay 2 (Y/A) is not used.  
Pipe sensor is required for 2 pipe auto changeover and 2 pipe auxiliary heat applications.  
2
IMPORTANT  
1
-1/8  
The thermostats are line voltage powered devices. All  
wiring must comply with national and local electrical  
codes, ordinances and regulations. Provide disconnect  
means and overload protection, as required.  
5
-13/16 (148)  
(29)  
The TB8575A1016 thermostat must be powered by an  
Approved 24 Vac, Class 2, NEMA rated transformer  
(such as a W6380 Relay Control Center).  
3
-13/16  
97)  
(
Location  
The thermostats are the temperature control element in a  
fan coil or air-conditioning system. They must be located  
about 1.5m (5 ft.) above the floor, in a position with good  
air circulation, to sense room temperature.  
THERMOSTAT  
SUB-BASE  
1-3/16  
(30)  
3-1/4 (83)  
IMPORTANT  
Do not mount the device where it can be affected by:  
5
/32  
4)  
1
2
3
4
. Drafts or dead spots behind doors or in corners.  
. Hot or cold air from ducts.  
. Radiant heat from the sun or appliances.  
. Unheated (uncooled) areas such as an outside  
wall behind the thermostat.  
(
5
(
/32  
4)  
UP  
1-3/4  
(44)  
5
. Concealed pipes or chimneys.  
2
-3/8 (60)  
M27589  
Mounting and Wiring  
Fig. 1. Dimensions in inches (mm).  
CAUTION  
Equipment damage hazard.  
Operation at low temperatures can cause fan  
coil damage.  
INSTALLATION  
This thermostat is not a safety device. Do not use  
it where the space temperature is outside of the  
device operating range.  
When Installing this Product…  
1.  
2.  
3.  
Read these instructions carefully. Failure to follow  
them could damage the product or cause a hazard-  
ous condition.  
Check the ratings given in the instructions and on  
the product to make sure the product is suitable for  
your application.  
A display of two dashes, – –, for the Room Temp  
display indicates a sensor failure or a temperature  
outside of the thermostat operating range of 18°C  
to 49°C (0°F to 120°F). With – – displayed, the  
thermostat ceases to operate. When the  
temperature returns to within its operating limits,  
the thermostat returns to operation.  
Installer must be a trained and experienced service  
technician.  
The optional freeze protect feature should be used  
if low temperatures can occur.  
WARNING  
Risk of electrical shock.  
Can cause severe injury, property damage or  
death.  
The thermostat must be mounted flush to the wall. The  
thermostat can be mounted directly to a 2 x 4 in.  
horizontal junction box (see Fig. 2 on page 4). An optional  
Disconnect power supply before installation and  
before servicing.  
3
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adaptor plate (50033847-001) can be used with a 4 x 4 in.  
or a vertical junction box for which mounting screws are  
supplied (see Fig. 3 on page 5).  
b. For the TB8575A1016 model (which does not  
have pre-wired fly leads):  
(1) Attach the supply wires directly to the termi-  
nals on the sub-base. See Table 3 on page 5  
for terminal identification.  
1.  
Prepare the supply wires:  
a. Mounting on a 4 x 4 in. or vertical 2 x 4 in.  
junction box:  
(
2) Push the supply wires back into the junction  
box.  
(
1) Feed the supply wires through the junction  
box and the opening in the adaptor plate.  
2) Affix the adaptor plate to the junction box  
using the screws provided.  
3
.
Mount the sub-base:  
a. Mounting on a 4 x 4 in. or vertical 2 x 4 in. junc-  
tion box:  
(
Align the two holes at the top edges of the sub-  
base with the two pins on the adaptor plate.  
Attach the sub-base to the adaptor plate using  
the screws provided.  
b. Mounting on a horizontal 2 x 4 in. junction box:  
Feed the supply wires through the opening of the  
junction box.  
2.  
Attach the supply wires:  
a. For the TB6575A1016,TB6575B1000 and  
TB6575C1016 models:  
b. Mounting on a horizontal 2 x 4 in. junction box:  
Attach the sub-base to the junction box using the  
screws provided.  
Thoroughly check the wiring to the sub-base before  
finally mounting the thermostat on the wall.  
Center the thermostat body over the sub-base, and  
press down firmly to engage the four tabs on the  
sub-base and snap the thermostat body into place.  
Use the provided safety screw to secure the ther-  
mostat main body to the sub-base.  
(
1) Push the fly lead wires through the wiring  
access hole in the sub-base.  
4
5
.
.
(
2) Attach the fly lead wires to the supply wires  
using wire nuts (not provided).See Table 3  
on page 5 for terminal and lead identifica-  
tion.  
6
7
.
.
(
3) Push the fly lead and supply wires back into  
the junction box.  
If using the adaptor plate, press the adaptor plate  
screw cover into place.  
SUBBASE  
MOUNT SUBBASE TO  
HORIZONTAL 2X4  
JUNCTION BOX USING  
TWO SCREWS  
SNAP MAIN BODY  
ONTO SUBBASE  
INSERT SCREW TO LOCK  
MAIN BODY TO SUBBASE  
M27590  
Fig. 2. Mounting sub-base and thermostat to 2 x 4 in. junction box.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
ADAPTOR  
PLATE  
MOUNT ADAPTOR PLATE ONTO  
4X4 WIRING BOX OR 2X4  
VERTICAL JUNCTION BOX  
USING TWO SCREWS  
SUB-BASE  
MOUNT SUB-BASE  
ONTO WALL PLATE  
USING TWO SCREWS  
ADAPTOR  
PLATE  
SCREW HEAD  
COVER  
INSERT SCREW  
TO LOCK MAIN  
BODY TO  
SNAP MAIN BODY  
ONTO SUB-BASE  
SUB-BASE  
NOTE: MIDDLE HOLES OF ADAPTOR PLATE ARE USED FOR MOUNTING  
TO A 2X4 VERTICAL JUNCTION BOX. USE OUTER HOLES FOR  
MOUNTING TO A 4X4 WIRING BOX.  
M27591  
Fig. 3. Mounting sub-base and thermostat using the adaptor plate (50033847-001).  
Terminal Wiring  
Table 3 provides the terminal wiring for each model and  
application.  
•
•
•
•
•
•
•
•
Gm: Medium speed fan relay  
L: Line voltage power (120/240/277 Vac)  
N: Line voltage ground (120/240/277 Vac)  
Ps: Pipe sensor (optional)  
R: 24 Vac power  
Rs: Remote sensor (optional)  
SB: Remote setback (optional)  
Sc: Ground (required if remote sensor, pipe sensor,  
and/or remote setback are connected)  
W/Y: W = Heating; Y = Cooling (2 pipe only)  
Y/A: Y = Cooling; A = Electrical heater output  
NOTE: The TB6575A1016,TB6575B1000 and  
TB6575C1016 models have color coded fly  
leads attached to the terminals. Refer to  
Table 3 for the color codes.  
The Terminal Identifiers in Table 3 have the following  
meaning:  
•
•
•
•
•
C: Common 24 Vac  
Gh: High speed fan relay  
Gl: Low speed fan relay  
Table 3. Terminal Wiring.  
Terminals  
Model  
Application  
1
2
3
4
5
6
7
8
9
10 11  
TB6575A1016 — 120/240 Vac;  
TB6575C1016 — 120/240/277 Vac  
Terminal Identifier  
Fly lead wire color  
Rsa Scb SBc Psd  
Nonee  
L
W/Y  
Y/A  
Gl Gm  
Gh  
N
Black Orange Yellow Red Blue Brown White  
2
pipes; Heat only  
f
W
Og Rh  
O
2
2
2
4
4
2
4
pipes; Cool only  
Y
O
O
O
O
O
O
O
R
R
R
R
R
R
R
O
O
O
O
O
O
O
pipes; Heat or Cool with Manual Changeover  
pipes; Heat or Cool with Seasonal Changeover  
pipes; Heat and Cool with Manual Changeover  
pipes; Heat and Cool with Auto Changeover  
pipes; Heat or Cool with Auxiliary Heat  
pipes; Heat and Cool with Manual Changeover  
W/Y  
W/Y  
W
Y
Y
A
Y
W
W/Y  
W
or Auto Changeover  
TB6575B1000 — 120/240 Vac  
5
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Table 3. Terminal Wiring. (Continued)  
Terminals  
Model  
Application  
1
L
2
3
n/ai  
4
5
6
7
8
9
10 11  
Terminal Identifier  
Fly lead wire color  
Rsa Scb SBc Psd  
Nonee  
W/Y  
Gl Gm  
Gh  
N
Black Orange  
Red Blue Brown White  
2
2
2
2
pipes; Heat only  
pipes; Cool only  
W
O
O
O
O
R
R
R
R
O
O
O
O
Y
pipes; Heat or Cool with Manual Changeover  
pipes; Heat or Cool with Seasonal Changeover  
W/Y  
W/Y  
TB8575A1016 — 24 Vac  
Terminal Identifierj  
R
W/Y  
Y/A  
Gl Gm  
Gh  
C
Rsa Scb SBc Psd  
2
2
2
2
4
4
2
4
pipes; Heat only  
W
O
O
O
O
O
O
O
O
R
R
R
R
R
R
R
R
O
O
O
O
O
O
O
O
pipes; Cool only  
Y
pipes; Heat or Cool with Manual Changeover  
pipes; Heat or Cool with Seasonal Changeover  
pipes; Heat and Cool with Manual Changeover  
pipes; Heat and Cool with Auto Changeover  
pipes; Heat or Cool with Auxiliary Heat  
pipes; Heat and Cool with Manual Changeover  
W/Y  
W/Y  
W
Y
Y
A
Y
W
W/Y  
W
or Auto Changeover  
a
b
c
d
e
f
Rs; Remote sensor is optional.  
Required when Rs, SB, or Ps is wired.  
SB; Remote setback is optional.  
Pipe sensor: Discrete, Analog, or Aquastat®.  
These terminals (8, 9, 10, and 11) do not have lead wires attached to them.  
A check mark (ü) indicates the terminal is used in that application. Rs and SB terminal connections are optional. If a  
terminal is left blank, it is not used in that application.  
g
h
i
O = Optional  
R = Required if Rs, SB, or Ps is wired.  
Terminal 3 is not used on the TB6575B1000 model.  
The TB8575A1016 model does not have fly lead wires attached to any terminals.  
j
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
NOTE: For complete wiring instructions, please  
follow the installation instructions provided  
with the remote sensor.  
Accessory Wiring  
Remote Pipe Sensor Wiring  
The remote pipe sensor is used for 2 pipes auto and 2  
pipes heat and cool with auxiliary heat changeover. The  
pipe sensor will sense the temperature in the pipes to tell  
the thermostat when the system is set for Heat or Cool.  
Sensor Wiring for Temperature  
Averaging  
Fig. 4–Fig. 6 illustrate sensor wiring for temperature  
averaging applications.  
1
.
Check Installer Setup Number (IS) 5 to ensure it is  
set to the desired value. (See Table 4 on page 11).  
Wire pipe sensor to Sc and Ps terminals.  
Attach pipe sensor to the pipe.  
SUBBASE  
2.  
3.  
4.  
5.  
Rs  
Sc  
TR21  
T
Insulate pipe sensor, as necessary.  
TR21  
T
Change pipe sensor thresholds for cooling or heat-  
ing by setting Installer Setup Numbers (IS) 6 and 7  
to desired values.  
T
T
Remote Temperature Sensor Wiring  
The TR21 is an optional remote temperature sensor that  
can be used as an alternative to the internal sensor. In  
addition to the TR21, other sensors that use a 20k Ohm  
curve may be used as the remote sensor.  
TR21  
T
TR21  
T
T
T
WARNING  
Risk of electrical shock.  
Can cause severe injury, property damage or  
death.  
M27559  
Fig. 4. Wiring four TR21 (20K ohm) sensors.  
Disconnect power supply before servicing.  
SUBBASE  
Rs  
Sc  
CAUTION  
Erratic system operation hazard.  
Failure to follow proper wiring practices can  
introduce disruptive electrical interference  
(noise).  
T4  
T3  
T4  
T3  
Keep wiring at least one foot away from large  
inductive loads such as motors line starters,  
lighting ballasts, and large power distribution  
panels. Shielded cable is required in installations  
where these guidelines cannot be met. Ground  
shield only to grounded controller case.  
1
1
TR21-A  
TR21-A  
1
THE TR21-A IS A 10K OHM SENSOR.  
M27560  
IMPORTANT  
All wiring must comply with local electrical codes and  
ordinances or as specified on installation wiring dia-  
grams.  
Fig. 5. Wiring two TR21-A (10K ohm) sensors to  
provide a temperature averaging network.  
—
Wall module wiring can be sized from 16 to 22  
AWG (1.31 to 0.33 sq. mm) depending on the  
application.  
SUBBASE  
Rs  
Sc  
—
—
The maximum length of wire from the thermostat  
to a wall module is 1000 ft. (305 m).  
Twisted pair wire is recommended for wire runs  
longer than 100 ft. (30.5 m).  
TR21  
T
T
T4  
T3  
1
.
Check Installer Setup Number (IS) 4 to ensure it is  
set to use the remote sensor. (See Table 4 on  
page 11).  
Wire sensor to Rs and Sc thermostat terminals.  
Push excess wire back into the hole. Plug the hole  
using non-hardening caulk, putty or insulation to  
prevent drafts from affecting performance.  
Remove sensor cover.  
1
TR21-A  
2
.
.
TR21  
T
3
T
4
.
.
5
Mount sensor to the wall or junction box using the  
screws and anchors provided.  
6
.
.
Level the sensor for appearance only. Device func-  
tions correctly even when not level.  
Replace sensor cover.  
1
THE TR21-A IS A 10K OHM SENSOR.  
M27561  
7
Fig. 6. Wiring two TR21 (20K ohm) sensors and  
one TR21-A (10K ohm) sensor to provide  
a temperature averaging network.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Thermostat Wiring Diagrams  
L
W/Y  
Y/A  
GI  
L (HOT)  
The figures in this section illustrate typical wiring for:  
VALVE  
FAN  
•
TB6575A1016,TB6575B1000 and TB6575C1016 fan  
coil thermostats, which are 120/240/277 Vac powered.  
Refer to Fig. 7–Fig. 13, beginning on page 8.  
TB8575A1016 model, which is 24 Vac powered. Refer  
to Fig. 14–Fig. 20, beginning on page 9.  
•
Gm  
Gh  
N
N
Rs  
REMOTE SENSOR  
Sc  
1
20/240/277 Vac Wiring Diagrams  
REMOTE SETBACK  
SB  
Ps  
PIPE SENSOR  
M27569  
(TB6575A/B/C)  
Fig. 10. Two pipes (Heat or Cool) Auto Changeover  
wiring diagram (120/240/277 Vac shown).  
L
W/Y  
Y/A  
GI  
L (HOT)  
HEAT VALVE  
FAN  
L
W/Y  
Y/A  
GI  
L (HOT)  
Gm  
Gh  
N
HEAT VALVE  
COOL VALVE  
N
Rs  
REMOTE SENSOR  
REMOTE SETBACK  
Gm  
Gh  
N
FAN  
Sc  
SB  
Ps  
N
Rs  
M27566  
REMOTE SENSOR  
REMOTE SETBACK  
Sc  
Fig. 7. Two pipes Heat-only wiring diagram  
SB  
Ps  
(
120/240/277 Vac shown).  
M27570  
Fig. 11. Four pipes (Heat and Cool) Manual/Auto  
L
W/Y  
Y/A  
GI  
L (HOT)  
changeover wiring diagram (120/240/277 Vac shown).  
COOL VALVE  
L
W/Y  
Y/A  
GI  
L (HOT)  
Gm  
Gh  
N
FAN  
VALVE  
AUX  
N
REMOTE SENSOR  
Rs  
Gm  
Gh  
N
FAN  
Sc  
REMOTE SETBACK  
M27567  
SB  
Ps  
N
Rs  
REMOTE SENSOR  
Sc  
Fig. 8. Two pipes Cool-only wiring diagram  
REMOTE SETBACK  
PIPE SENSOR  
M27571  
SB  
Ps  
(
120/240/277 Vac shown).  
Fig. 12. Two pipes (Heat or Cool) with Auxiliary Heat  
and Manual Changeover wiring diagram (120/240/277  
Vac shown).  
L
W/Y  
Y/A  
GI  
L (HOT)  
VALVE  
Gm  
Gh  
N
FAN  
N
REMOTE SENSOR  
Rs  
Sc  
REMOTE SETBACK  
M27568  
SB  
Ps  
Fig. 9. Two pipes (Heat or Cool) Manual Changeover  
wiring diagram (120/240/277 Vac shown).  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
.
R
L
W/Y  
Y/A  
GI  
L (HOT)  
W/Y  
Y/A  
GI  
VALVE  
HEAT VALVE  
COOL VALVE  
FAN  
Gm  
Gh  
C
FAN  
1
2
Gm  
Gh  
N
5
L1  
(HOT)  
3
24 VAC  
N
4
L2  
1
Rs  
Sc  
Rs  
REMOTE SENSOR  
REMOTE SENSOR  
REMOTE SETBACK  
Sc  
REMOTE SETBACK  
SB  
Ps  
SB  
Ps  
1
2
REMOVE PRE-WIRED WIRE FROM TERMINAL 5 (MID FAN SPEED).  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
M27575  
JUMPER TERMINALS 5 AND 6 (MID AND HIGH FAN SPEEDS). FAN  
MEDIUM SETTING WILL OPERATE ON HIGH SPEED.  
Fig. 16. Two pipes (Heat or Cool) Manual Changeover  
wiring diagram (24 Vac shown).  
3
4
5
CONNECT TERMINAL 7 TO THE MID FAN SPEED WIRE FROM THE  
PREVIOUS SYSTEM.  
REWIRE THE PREVIOUS MID SPEED FAN WIRE TO THE NEUTRAL  
CIRCUIT IN THE SYSTEM.  
CHANGE INSTALLER SETUP IS CODE 9 TO 2 FOR 2 SPEED FAN  
R
CONTROL.  
M31328A  
W/Y  
Y/A  
GI  
VALVE  
Fig. 13. Wiring diagram when missing a wire for  
electromechanical retrofit (120/240/277 Vac shown).  
Gm  
Gh  
C
FAN  
L1  
(
HOT)  
2
4 VAC  
L2  
2
4 Vac Wiring Diagrams (TB8575)  
For the TB8575A1016 model, a 24 Vac Class 2 NEMA  
rated transformer must be used.  
1
Rs  
Sc  
REMOTE SENSOR  
REMOTE SETBACK  
PIPE SENSOR  
SB  
Ps  
R
W/Y  
Y/A  
GI  
HEAT VALVE  
FAN  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
M27576  
Fig. 17. Two pipes (Heat or Cool) auto changeover  
wiring diagram (24 Vac shown).  
Gm  
Gh  
C
L1  
(
HOT)  
2
4 VAC  
L2  
1
Rs  
Sc  
R
REMOTE SENSOR  
REMOTE SETBACK  
W/Y  
Y/A  
GI  
HEAT VALVE  
COOL VALVE  
SB  
Ps  
Gm  
Gh  
C
FAN  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
M27573  
L1  
(HOT)  
2
4 VAC  
L2  
1
Fig. 14. Two pipes Heat-only wiring diagram (24 Vac  
shown).  
Rs  
Sc  
REMOTE SENSOR  
REMOTE SETBACK  
SB  
Ps  
R
W/Y  
Y/A  
GI  
COOL VALVE  
FAN  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
M27577  
Fig. 18. Four pipes (Heat and Cool) Manual/Auto  
Changeover wiring diagram (24 Vac shown).  
Gm  
Gh  
C
L1  
(
HOT)  
2
4 VAC  
L2  
1
Rs  
Sc  
REMOTE SENSOR  
REMOTE SETBACK  
SB  
Ps  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
M27574  
Fig. 15. Two pipes Cool-only wiring diagram (24 Vac  
shown).  
9
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
If it is necessary to remove the thermostat from the sub-  
base, refer to Fig. 21 and perform the following steps:  
R
1
.
Turn off the thermostat by pressing the system  
button until OFF displays.  
W/Y  
Y/A  
GI  
VALVE  
AUX  
2
3
.
.
Remove the power source from the thermostat.  
Remove the small safety screw at the bottom of the  
thermostat.  
Gm  
Gh  
C
FAN  
L1  
4. Use both hands to pull the thermostat straight away  
(
HOT)  
2
4 VAC  
from the sub-base.  
L2  
1
Rs  
Sc  
REMOTE SENSOR  
REMOTE SETBACK  
PIPE SENSOR  
SB  
Ps  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
M27578  
Fig. 19. Two pipes (Heat or Cool) with Auxiliary Heat  
and Manual Changeover wiring diagram (24 Vac  
shown).  
.
L
W/Y  
Y/A  
GI  
HEAT VALVE  
COOL VALVE  
M27592  
FAN  
Fig. 21. Removing the thermostat.  
1
2
Gm  
Gh  
C
6
24 VAC  
L1  
5
3
(HOT)  
L2  
SETUP  
The thermostat provides an LCD display, two buttons  
below the display for System and Fan control and two  
adjustment buttons (Up and Down) to the right of the  
display. See Fig. 23.  
Rs  
Sc  
4
REMOTE SENSOR  
REMOTE SETBACK  
SB  
Ps  
1
2
REMOVE PRE-WIRED WIRE FROM TERMINAL 5 (MID FAN SPEED).  
JUMPER TERMINALS 5 AND 6 (MID AND HIGH FAN SPEEDS). FAN  
MEDIUM SETTING WILL OPERATE ON HIGH SPEED.  
Settings, including setpoints, are permanently retained in  
EEPROM in case of a power outage.  
3
4
5
6
CONNECT TERMINAL 7 TO THE MID FAN SPEED WIRE FROM  
PREVIOUS SYSTEM.  
Fig. 22 illustrates all the possible LCD display elements.  
Only those elements pertinent to the current settings and  
status (including the text for the two buttons, System and  
Fan), actually display.  
REWIRE THE PREVIOUS MID FAN SPEED WIRE TO THE NEUTRAL  
CIRCUIT IN THE SYSTEM.  
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
CHANGE INSTALLER SETUP IS CODE 9 TO 2 FOR 2 SPEED FAN  
CONTROL.  
M31329A  
ºF ºC  
Freeze Set to  
Protect Setup  
Set to RoomTemp  
Locked  
Fig. 20. Wiring diagram when missing a wire for  
electromechanical retrofit (24 Vac shown).  
Test  
ºF ºC  
Economy  
Setback  
Pipe  
Removing the Thermostat  
Sensor  
Heat On Cool On  
OffHeatAutoCool LowMedHiAuto  
Fan On  
WARNING  
Risk of electrical shock.  
Can cause severe injury, property damage or  
death.  
M27584  
Disconnect power supply before servicing.  
Fig. 22. LCD display with all possible elements  
shown.  
CAUTION  
Equipment damage hazard.  
Improper removal can damage the thermostat.  
Carefully follow the thermostat removal directions.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Installer Setup (IS) Mode  
To enter Installer Setup Mode:  
UP AND DOWN  
ARROW BUTTONS  
•
Press and hold both the System button (labeled  
Heat/Cool) and the Up Arrow button for three (3)  
seconds.  
Set to  
RoomTemp  
ºF  
This displays the setup screen on the LCD. See Fig. 24.  
ºF  
NOTE: Exiting Installer Setup Mode is the same as  
the method for entering setup mode.  
Heat On  
Heat  
Fan On  
Auto  
Table 4 provides the setup codes (IS codes) and values.  
To enter the setup parameters:  
1
.
Press the System (Heat/Cool) button to cycle  
through the IS codes, which display in the upper  
right following the word Setup.  
M27586  
2. Press the Up or Down Arrow buttons to cycle  
through the option values for the currently displayed  
IS code. The values display in the center of the  
screen.  
SYSTEM  
BUTTON  
FAN  
BUTTON  
Fig. 23. LCD display showing default screen.  
3
.
After the desired value displays, press the System  
button to store your value selection and display the  
next IS code.  
Power-up  
At power-up, the thermostat’s LCD shows all display  
segments for two seconds, enters a self-test mode for a  
few seconds, and then displays the current room  
temperature (default screen), as shown in Fig. 23.  
Setup  
NOTE: If there is a temperature sensor failure or the  
temperature is outside of the operating  
range, the room temperature display shows  
two dashes, — —.  
When the sensor returns to its operating  
range, the temperature display resumes.  
M27585  
CAUTION  
Fig. 24. Installer Setup (IS) mode screen.  
Equipment damage hazard.  
Power overload will damage the thermostat.  
The thermostat has a safety fuse rated at 15 A/  
2
50 Vac. If the fuse blows, the thermostat must be  
replaced. The fuse is not field replaceable.  
This fuse is provided as a safety feature to prevent  
fire if the thermostat is overloaded.  
Table 4. Installer Setup (IS) Codes and Options.  
IS  
Option  
Option Description (Default value shown in  
Bold)  
Code Code Description Value  
Notes  
1
Line Voltage  
Selection  
0
1
2
120 Vac power supply (Default)  
240 Vac power supply  
277 Vac power supply  
1
1
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Table 4. Installer Setup (IS) Codes and Options. (Continued)  
IS  
Option  
Option Description (Default value shown in  
Bold)  
Code Code Description Value  
Notes  
2
System Type  
0
1
2
3
Heat only  
Cool only  
Two pipes: Heat or Cool; Manual Changeover  
Two pipes: Heat or Cool; Seasonal Changeover  
(requires optional pipe sensor)  
4
5
6
Four pipes: Manual Changeover  
TB6575A,TB6575B and  
TB6575C only  
Four pipes: Auto Changeover  
TB6575A,TB6575B and  
TB6575C only  
Two pipes: Heat or Cool; with Auxiliary Heat  
Allows auxiliary heat to turn  
on when pipes have cold  
water  
(requires optional pipe sensor).  
(
TB6575A,TB6575B and  
TB6575C only).  
7
Four pipes: Manual and Auto Changeover  
Default)  
TB6575A,TB6575B and  
TB6575C only  
(
2.5  
Fan On/Off  
Selection for Aux  
Heat On  
0
1
Fan ON when Auxiliary Heat is on (Default)  
Enables or disables the  
auto fan operation when  
Auxiliary Heat is On  
Fan OFF when Auxiliary Heat is on  
(
TB6575A,TB6575B and  
TB6575C only).  
3
4
5
Valve Output Type  
Space Sensor Type  
Pipe Sensor  
0
1
0
1
0
Valve energized on call for heat or cool (Default)  
Valve de-energized on call for heat or cool  
Onboard Sensor (Default)  
Remote Sensor (TR21 or other 20K Ohm sensor)  
Contact Open = Cool mode; Contact Closed = Heat  
mode  
•
•
Pipe sensor will flash on  
display screen if analog  
input (#4) is lost.  
Pipe sensor status and  
water temperature can  
be checked in test mode  
Only displays when  
value 3 or 6 for the  
System Type in IS  
code #2 is selected.  
1
2
3
4
Contact Open = Heat mode; Contact Closed = Cool  
mode  
Contact Open = Heat mode; Contact Closed = Cool  
mode (same as 1)  
(
see “Installer Test (IT)  
Mode” on page 14 for  
details)  
Contact Open = Cool mode; Contact Closed = Heat  
mode (same as 0)  
Analog input (Default). NTC20K, whose curve is  
the same as TR21.  
Only displays when system type 3 or 6 is selected.  
6
7
8
Pipe Sensor  
Threshold for  
Cooling  
50 to Range is 50°F to 72°F. Default is 60°F.  
Changes to Cool when pipe  
temperature is below  
threshold.  
72  
Pipe Sensor  
Threshold for  
Heating  
75 to Range is 75°F to 90°F. Default is 80°F.  
90  
Changes to Heat when pipe  
sensor temperature is  
above threshold.  
Temperature Scale  
0
1
0
Degrees Fahrenheit (°F); Default.  
Degrees Celsius (°C).  
8
.5 Fan Speed at motor  
start up  
Provide full power when fan motor starts –  
always starts in high fan speed (Default)  
High speed start up  
ensures that there is  
enough torque to start the  
motor and eliminates and  
motor locking.  
1
Disable – fan will start at speed that is needed as  
defined by VersaSpeed  
9
Number of Fan  
Speeds  
1
2
3
0
1
Single Speed Fan  
2 Speed Fan  
Low speed only  
Hi and Low speed fans only  
Hi, Med, and Low speed fan  
3 Speed Fan (Default)  
Constant and Auto (Default)  
Auto only  
9
.5 Fan Control Type  
When fan is in Auto, the fan  
ramping algorithm,  
VersaSpeed, is used  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Table 4. Installer Setup (IS) Codes and Options. (Continued)  
Option Option Description (Default value shown in  
IS  
Code Code Description Value Bold)  
Notes  
10  
Control Method for  
-Pipe Auto  
Changeover  
1
Single Setpoint (Default)  
Uses switching differential  
to change between heating  
and cooling and controls to  
a single setpoint (Only  
4
displayed for system types  
5
or 7)  
2
Heat and Cool Setpoints (2 setpoint method)  
Uses a deadband of no  
control and controls to a  
heat or cool setpoint. (Only  
displayed for system types  
5
or 7)  
1
0.5 Deadband for Heat/ 2 to 9 Range is 2 to 9. Default is 3. Deadband = minimum Available when Heat and  
Cool Setpoints  
distance between heating and cooling setpoints.  
Cool Setpoints are chosen  
for the control method for 4-  
pipe Auto (IS 10)  
Switching  
Differential for  
Single Setpoint  
2 to 6 Range is 2 to 6. Default is 3. Heat switching point = Available when Single  
setpoint - switching differential. Cool switching point Setpoint is chosen for the  
= setpoint + switching differential.  
control method for 4-pipe  
Auto (IS 10)  
1
1
CPH Value for Heat 1 to 12 Range is 1 to 12. Default is 4.  
CPH Value for Cool 1 to 6 Range is 1 to 6. Default is 3.  
The number selected  
indicates the maximum  
times Heating is cycled on  
per hour (CPH). IS 2  
selection is 5.  
1
2
3
The number selected  
indicates the maximum  
times Cooling is cycled on  
per hour (CPH).  
1
CPH for Auxiliary  
Electrical Heater  
1 to 12 Range is 1 to 12. Default is 6.  
The number selected  
indicates the maximum  
times Auxiliary Heating is  
cycled on per hour (CPH).  
1
4
5
Display  
Temperature  
Adjustment  
-4 to 4 Range is -4°F to +4°F; Default is 0°F.  
1
Temperature  
Display Mode  
0
1
2
Display Room Temperature  
Display Setpoint  
Display Temperature and Setpoint; Default.  
16  
17  
18  
Setpoint Range  
Stop for Heating  
50 to Range is 50°F to 90°F. Default is 90°F.  
90  
Setpoint Range  
Stop for Cooling  
50 to Range is 50°F to 90°F. Default is 50°F.  
90  
Keypad Lockout  
0
1
2
3
All keys are available (Default)  
The System button (Heat/Cool) is locked out  
Both the System and Fan buttons are locked out.  
All buttons are locked out (System, Fan, Up Arrow,  
and Down Arrow). The LCD displays LOCKED.  
1
3
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Table 4. Installer Setup (IS) Codes and Options. (Continued)  
IS  
Option  
Option Description (Default value shown in  
Bold)  
Code Code Description Value  
Notes  
19  
Remote Setback  
0
1
Disabled  
Hotel card enabled N.O. for unoccupied mode with  
second software delay going from UnOccupied to  
Occupied;  
minute delay going from Occupied to UnOccupied.  
Hotel Card enabled N.C. for unoccupied mode with  
second software delay going from UnOccupied to  
Occupied;  
minute delay going from Occupied to UnOccupied.  
Hotel Card enabled N.O. for unoccupied mode with  
second software delay going from UnOccupied to  
Occupied;  
0 minute delay going from Occupied to  
1
2
2
3
1
2
1
3
UnOccupied  
4
Hotel Card enabled N.C. for unoccupied mode with  
1
second software delay going from UnOccupied to  
Occupied;  
0 minute delay going from Occupied to  
3
UnOccupied.  
5
Button Press (Default)  
Press and hold “Heat/Cool/  
Off” button for 3 seconds  
and thermostat will go into  
“
Economy Setback”  
2
2
2
0
1
2
Remote Setback for 50 to Range is 50°F to 70°F. Default is 64°F.  
Heating 70  
Used when the thermostat  
is in the Unoccupied state.  
Remote Setback for 72 to Range is 72°F to 90°F. Default is 79°F.  
Cooling  
90  
Activity Sensing  
0
Disabled (Default)  
4 hour sensing  
8 hour sensing  
12 hour sensing  
16 hour sensing  
20 hour sensing  
24 hour sensing  
Disabled  
This will be selectable when  
IS 19 is set to option 0 or 5.  
If IS 19 is configured for  
N.O or N.C, activity sensing  
will not be available.  
1
2
3
4
5
6
2
3
4
Freeze Protection  
Auto Fan Reset  
0
This feature can not  
activate when the  
application is Cool only.  
This function only occurs  
when System switch is set  
to OFF.  
1
Enabled (Default) – Stat cycles On Heat when  
room temperature reaches 40°F (4°C), and disables  
Heat when room temperature reaches below 46°F  
(8°C). The LCD displays FREEZE PROTECT  
2
0
Inactive (Default)  
Auto Fan Reset is not  
allowed (does not display)  
when the fan control type is  
set to Auto Only, (IS code  
1
Resets back to Auto after 2 hours. The start time is  
calculated after the initial call for Heat/Cool is  
satisfied. Then, the two (2) hour timing begins.  
#
9 - value 1).  
2
Resets back to Auto after 4 hours. The start time is  
calculated after the initial call for Heat/Cool is  
satisfied. Then, the four (4) hour timing begins.  
25  
Purge Cycle  
Frequency  
0
1
2
No periodic purge (other purges still apply)  
Purge every 2 hours (Default)  
Purge every 24 hours  
Option 1 Default is normally  
recommended to make sure  
changeover is detected  
quickly on spring and fall  
days.  
Table 5 provides the Test codes (IT codes) and values. To  
enter the IT codes:  
1. Press the System (Heat/Cool) button to cycle  
through the IT codes, which display in the upper  
right above the word Test.  
Installer Test (IT) Mode  
To enter Installer Test Mode:  
•
Press and hold both the Up arrow button and the  
Down Arrow button for three (3) seconds.  
2
.
Press the Up or Down Arrow buttons to cycle  
through the values for the currently displayed IT  
code. The values display in the center of the screen.  
This displays all segments of the LCD screen on the LCD.  
See Fig. 22 on page 10.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
3.  
After the desired value displays, press the System  
button to store your value selection and display the  
next IT code.  
OPERATION  
PROPORTIONAL + INTEGRAL  
(P+I) CONTROL  
NOTE: Exiting Installer Test Mode is the same as the  
method for entering test mode,  
Like a mechanical thermostat, the fan coil thermostats  
have On/Off control output. However, this output is  
regulated by a P+I algorithm, enabling the thermostat to  
control closer to setpoint than conventional thermostats.  
This results in performance where the space temperature  
is maintained within 0.75°C (1.5°F) of the setpoint  
regardless of fan speed.  
Test  
NOTE: Integral action corrects the temperature con-  
trol errors of proportional-only control, but it  
is slower to react to large temperature or set-  
point changes.  
M27587  
Economy Setback Modes  
Fig. 25. Installer Test (IT) mode screen.  
ACTIVITY SENSING (IS CODE #22)  
If Activity Sensing is enabled, any time the thermostat is  
not touched (no single key is pressed) for the duration  
selected, the thermostat automatically falls back into the  
Economy Setback. The LCD displays ECONOMY  
SETBACK just to the right of the main temperature display  
to indicate Activity Sensing mode is active. When any key  
is pressed, the thermostat controls to Occupied mode.  
Table 5. Installer Test (IT) Codes and Options.  
IT  
Code  
Code  
Description  
Option  
Value Option Description  
1
2
3
4
0
0
0
0
Heat Control  
0
1
0
1
0
1
0
1
2
3
Close  
Open  
Auxiliary Heat  
Control  
Close  
BUTTON PRESS SETBACK (IS CODE #19-5)  
The default remote setback option is for economy setback  
via a button press on the thermostat. In this mode, the  
thermostat can quickly be setback by pressing and  
holding down the System Mode button for more than 3  
seconds. The LCD displays ECONOMY SETBACK just to  
the right of the main temperature display to indicate the  
Setback is active. When any key is pressed, the  
thermostat controls to Occupied mode.  
Open  
Cool Control  
Close  
Open  
Fan Control  
Close  
Low Speed  
Medium Speed  
High Speed  
REMOTE SETBACK (IS CODE #19)  
5
0
Pipe Sensor  
32-199 Displays the pipe  
sensor temperature.  
Only used for System  
Type 3 or 6 (IS code  
Remote Setback is activated by a dry contact closure on  
the remote setback input from an occupancy sensor, time  
switch, or hotel card key. The thermostat controls to the  
user/installer defined setback setpoints for increased  
energy savings. The LCD displays Economy Setback just  
to the right of the main temperature display to indicate the  
Remote Setback mode is active.  
#2, value 3 or 6). Only  
the Analog pipe sensor  
is tested.  
71  
72  
73  
74  
Software Main  
version  
01-99 A 2-digit number, 01-99  
01-99 A 2-digit number, 01-99  
01-99 A 2-digit number, 01-99  
01-99 A 2-digit number, 01-99  
When Remote Setback is active, all buttons on the  
thermostat are disabled. However, the button  
combinations to access Installer Setup (IS) and Installer  
Test (IT) remain enabled.  
Software Vice  
version  
Configuration  
Data Main version  
ECONOMY SETBACK OPERATION  
For Heat Mode, when Economy Setback is enabled, the  
set point changes to the remote setback heating setpoint  
Configuration  
Data Vice version  
(
IS CODE #20).  
7
5
6
Week Produced  
Year Produced  
01-52 A 2-digit number, 01-52  
08-99 A 2-digit number, 08-99  
For Cool Mode, when Economy Setback is enabled, the  
set point changes to the remote setback cooling setpoint  
7
(
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.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
•
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.  
REMOTE SETBACK COOL SETPOINT  
UNOCCUPIED DEADBAND  
COOL SETPOINT  
DEADBAND  
Application Modes  
HEAT SETPOINT  
2
PIPE SEASONAL CHANGEOVER APPLICATIONS  
UNOCCUPIED DEADBAND  
These applications require the pipe sensor as a N.O,  
N.C., or Analog Input to detect seasonal changeover:  
REMOTE SETBACK HEAT SETPOINT  
M27562  
•
•
2 pipes with auto changeover  
2 pipes with auxiliary heat  
Fig. 26. Auto Changeover with Heat/Cool Setpoints  
deadband illustration.  
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.  
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.  
2
Pipes with Auto Changeover  
REMOTE SETBACK COOL SETPOINT  
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.  
UNOCCUPIED DEADBAND  
COOL SWITCHING POINT  
SETPOINT  
HEAT SWITCHING POINT  
UNOCCUPIED DEADBAND  
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.  
REMOTE SETBACK HEAT SETPOINT  
M31331  
Fig. 27. 4 Pipe Auto Changeover with Single Setpoint  
and Economy Setback Deadband Illustration  
Table 6. Logic for 2 Pipes with Auto Changeover  
Fan Modes  
Pipe Temperature after purge  
System Mode  
Heat  
>
Threshold for Heating (IS code 7)  
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.  
Between Thresholds  
After Purge Occurs  
Fan Only*  
<
Threshold for Cooling (IS code 6)  
Cool  
The fan ramping algorithm is illustrated in Fig. 28  
*
If pipe temperature is between the two threshold values  
after the 5 minute purge occurs, the thermostat will  
activate a second 5 minute purge to double check the  
water temperature. If after the second 5 minute purge, the  
water temperature is still between the two thresholds, the  
valve output will be disabled and only manual fan will be  
available. It will stay in this operation until the next purge  
cycle occurs.  
FAN SPEED IS HIGH  
+
4°F  
FAN SPEED IS MEDIUM  
FAN SPEED IS LOW  
FAN SPEED IS LOW  
DIFFERENCE  
BETWEEN  
RT AND  
COOL  
+
2°F  
SETPOINT  
SETPOINT  
-
2°F  
4°F  
FAN SPEED IS MEDIUM  
2
Pipes with Auxiliary Heat  
-
For this application, when there is hot water in the pipes,  
the system switch provides “Off” and “Heat.” When there  
is cold water in the pipes, the system switch provides  
FAN SPEED IS HIGH  
HEAT  
M27563  
"Off," "Heat," and "Cool."  
Fig. 28. VersaSpeed™ fan ramping algorithm  
illustration.  
Operation:  
After exiting the installer setup, the thermostat will perform  
a 5 minute purge. During this time, the valve (W/Y) will  
energize and the fan and auxiliary heat (Y/A) will be de-  
energized. After the 5 minute purge, the thermostat will go  
into the appropriate mode as described by Table 7.  
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.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Table 7. Logic for 2 Pipes with Auxiliary Heat  
Pipe  
4 PIPES AUTO CHANGEOVER  
Single Set Point Method  
Temperature  
After Purge  
In 4 pipe auto changeover with a single setpoint, the  
temperature is always controlled to the setpoint. Switching  
points are used to determine when to switch between  
heating and cooling modes. If the current mode is heat  
and the temperature drifts above the cool switch point  
Heat Mode  
Valve (W/Y)  
energized on calls Mode changes to  
Cool Mode  
>
Threshold  
for Heating  
Changeover.  
(
IS code 7)  
for heat  
Heat.  
(
Setpoint + Switching Differential), the thermostat will  
Between  
Thresholds  
After Purge  
Occurs  
Aux Heat (Y/A)  
energized on calls changes to Heat  
for heat  
Changeover. Mode  
switch to heat operation and will heat the space until  
setpoint is reached.  
because Cool is not  
available.  
For this application, the setpoint setting and switching  
points are illustrated in Fig. 29. The switching differential  
is defined via IS code 10.  
<
Threshold  
for Cooling  
IS code 6)  
Mode stays in Heat Valve (W/Y)  
but Aux Heat (Y/A) energized on calls  
energized on calls for cool  
for heat  
(
If pipe temperature is between the two threshold values  
after the 5 minute purge occurs, the thermostat will  
activate a second 5 minute purge to double check the  
water temperature. If after the second 5 minute purge, the  
water temperature is still between the two thresholds, the  
valve output will be disabled and only auxiliary heat will be  
available for heating.  
COOL SWITCHING POINT  
SETPOINT  
SWITCHING  
DIFFERENTIAL  
HEAT SWITCHING POINT  
Auxiliary heat (Y/A) always de-energizes during purges.  
Purge Cycles for 2 Pipe Seasonal Changeover  
Applications  
For 2 Pipe with Auto Changeover and 2 Pipe with  
Auxiliary Heat applications, the thermostat will run purge  
cycles to determine if there is hot or cold water in the  
pipes.  
M31330  
Fig. 29. 4 Pipe Auto Changeover with Single Setpoint  
and Switching Points  
Heat/Cool Setpoint Method  
In 4 pipe auto changeover with heat and cool setpoints,  
the system key is used to switch between the heating  
setpoint and cooling setpoints. Use the Up and Down  
arrow buttons to change the setpoint.  
A 5 minute purge will occur every 2 or 24 hours (IS 25) to  
ensure that the pipe sensor is sensing the correct mode  
during seasonal changeover months.  
A 5 minute purge will also occur anytime the installer  
setup or installer test menus are exited, whenever the  
thermostat is switched from its “Off” position, and if the  
power is reset.  
For this application, the setpoint settings and deadband  
are illustrated in Fig. 30. The deadband is changed via IS  
code 10.  
NOTE: For the 2 Pipe with Auxiliary Heat application,  
the thermostat must be in the “Off” position  
for more than 30 minutes before a 5 minute  
purge will occur when it is switched back into  
COOLING SETPOINT  
DEADBAND  
HEATING SETPOINT  
M27565  
“Heat” or “Cool.”  
Fig. 30. 4 Pipe Auto Changeover setpoints and  
deadband.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
TROUBLESHOOTING  
Table 8 provides troubleshooting information.  
Table 8. Troubleshooting.  
Symptom  
Possible Cause  
Action  
Display does not  
come on.  
Thermostat is not being  
powered.  
For TB6575A/B/C, check for 120/240/277 Vac between L and N.  
For TB8575A, check for 24 Vac between R and C.  
Temperature settings The upper or lower  
Check the temperature setpoints for heating and cooling (Installer  
Setup codes 16 and 17 respectively). Modify as needed.  
do not change.  
temperature limits were  
reached.  
The keypad is fully locked. Change keypad locked options (Installer Setup code #18).  
Heating or cooling  
does not come on.  
System Type selection not Set the Installer Setup code #2 (System Type) to the correct value  
set to Heat or Cool or the to match the installed heating and/or cooling equipment. Verify  
selection is incorrect.  
operation of wiring and equipment in Installer Test mode.  
Thermostat is calling Heating or cooling  
for Heat (Heat on) or equipment is not  
Cool (Cool on) but no operating.  
heating or cooling is  
Check wiring. Check that the Installer Setup code #2 (System  
Type) value matches the installed heating and/or cooling  
equipment. Verify operation of equipment in Installer Test mode.  
running.  
Heat does not turn on Heating equipment failure. For TB6575A/B/C:  
(
Heat On is solid in  
1. Check for 120/240/277 Vac at the equipment between power  
the display).  
and common, (terminals L and N).  
2
.
Check for 120/240/277 Vac between the heat (W) and com-  
mon (N) terminals. If 120/240/277 Vac is present, the ther-  
mostat is functional.  
For TB8575A:  
1
.
Check for 24 Vac at the equipment on the secondary side of  
the transformer between power and common (terminals R  
and C).  
2
.
Check for 24 Vac between the heat terminal (W) and trans-  
former common. If 24 Vac is present, the thermostat is func-  
tional.  
If voltage is present, check the heating equipment to find the cause  
of the problem.  
Loose connection or  
broken wire between  
thermostat and heating  
equipment.  
For TB6575A/B/C:  
Check for 120/240/277 Vac between the heat (W) and common  
(N) terminals.  
For TB8575A:  
Check for 24 Vac between the heat terminal (W) and  
transformer common.  
If voltage is not present, check wire connection (loose or broken)  
between the thermostat and the heating equipment.  
Both the heating and Incorrect System Type  
cooling equipment are selected.  
running at the same  
Check that the Installer Setup code #2 (System Type) value  
matches the installed heating and/or cooling equipment.  
Heating and cooling wires Separate the shorted heating and cooling wires.  
time.  
are shorted together.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Table 8. Troubleshooting. (Continued)  
Possible Cause  
Cooling does not turn Cooling equipment failure. For TB6575A/B/C:  
Symptom  
Action  
on (Cool On is solid in  
the display).  
1. Check for 120/240/277 Vac at the equipment between power  
and common, (terminals L and N).  
2
.
Check for 120/240/277 Vac between the cool (Y) and com-  
mon (N) terminals. If 120/240/277 Vac is present, the ther-  
mostat is functional.  
For TB875A:  
1
.
Check for 24 Vac at the equipment on the secondary side of  
the transformer between power and common (terminals R  
and C).  
2
.
Check for 24 Vac between the cool terminal (Y) and trans-  
former common. If 24 Vac is present, the thermostat is func-  
tional.  
If voltage is present, check the cooling equipment to find the cause  
of the problem.  
Loose connection or  
broken wire between  
thermostat and cooling  
equipment.  
For TB6575A/B/C:  
Check for 120/240/277 Vac between the cool (Y) and common  
(N) terminals.  
For TB875A:  
Check for 24 Vac between the cool terminal (Y) and transformer  
common.  
If voltage is not present, check the wire connection (loose or  
broken) between the thermostat and the cooling equipment.  
Fan does not turn on Wiring or connection  
Check wiring and make sure the connection is correct.  
in a call for Heat.  
failure  
Cannot select fan  
speed.  
Fan Control Type  
selection is incorrect.  
Check that the Installer Setup code #9 (Fan Control) value is set to  
zero (0).  
Heating equipment is Incorrect System Type  
Check that the Installer Setup code #2 (System Type) value  
matches the installed heating and/or cooling equipment.  
running in the Cool  
mode.  
configured.  
Heating equipment  
does not turn off and configured.  
heat temperature  
Incorrect System Type  
Check that the Installer Setup code #2 (System Type) value  
matches the installed heating and/or cooling equipment.  
setting is set below  
room temperature  
(Heat On is not in the  
display).  
Cannot set the system System Type (Installer  
Set the Installer Setup code #2 value to match the installed heating  
and/or cooling equipment.  
setting to Heat.  
Setup code #2) is set to  
Cool Only (value = 1).  
Cannot set the system System Type (Installer  
Set the Installer Setup code #2 value to match the installed heating  
and/or cooling equipment.  
setting to Cool.  
Setup code #2) is set to  
Heat Only (value = 0).  
Heat On is not in the System Type setting is not Set the Installer Setup code #2 to Heat and set the temperature  
display.  
set to Heat and/or the setting above the room temperature.  
temperature setting is not  
set above the room  
temperature.  
Cool On is not in the System Type setting is not Set the Installer Setup code #2 to Cool and set the temperature  
display.  
set to Cool and/or the  
temperature setting is not  
set below the room  
temperature.  
setting below the room temperature.  
Remote sensor does Incorrect IS code.  
not display  
temperatures  
Set the Installer Setup code #4 to Remote (value = 1).  
Sensor is not compatible. The remote sensor must be TR21 or compatible 20K NTC.  
Remote Setback does Incorrect IS code.  
not activate  
Make sure the NO/NC and timer selection is correct. Check the  
value selected for IS code 19.  
Remote setpoint error.  
Make sure the remote setback setpoint is correct for energy saving  
usage.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
Table 8. Troubleshooting. (Continued)  
Possible Cause  
Symptom  
Action  
Activity Sensing does All buttons are locked.  
not exit when button  
Make sure keypad lockout is disabled. Set IS code 18, value = 0.  
pressed  
Freeze Protection  
does not activate  
System Type is set to  
Cool.  
Freeze protection is not activated when system type is Cool (IS  
code 2; value = 1). Change System Type.  
System mode is not Off. Set the System mode button to Off.  
Auto Fan Reset does Incorrect IS code.  
Set the Installer Setup code #24 to Enabled (value = 1 or 2).  
not activate  
Calling for Heat/Cool  
setpoint couldn't be  
satisfied.  
Only after the setpoint is satisfied, will the auto fan reset timer  
activate.  
Automation and Control Solutions  
Honeywell International Inc.  
1985 Douglas Drive North  
®
U.S. Registered Trademark  
Golden Valley, MN 55422  
customer.honeywell.com  
© 2013 Honeywell International Inc.  
2-0311—13 KK Rev. 10-13  
Printed in United States  
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