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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  
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•
Simple, intuitive user interface.  
Pre-installed lead wires for fast installation  
(TB6575A, TB6575B and TB6575C models only)  
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Backlight display permits easy viewing in any  
light.  
Four buttons allow manual control of system  
operation, fan speed, and temperature setpoint  
adjustment.  
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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.  
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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.  
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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.  
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•
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.  
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Selectable °C or °F display via Setup button on  
thermostat.  
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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:  
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Option to wire a remote indoor temperature  
sensor.  
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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  
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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:  
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120 Vac ±10% at 50/60Hz  
240 Vac -15% to +10% at 50/60Hz  
TB6575C1016:  
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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)).  
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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  
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20K Ohm: C7041B2005, C7041B2013,  
C7041C2003, C7041P2004, C7770A1006,  
C7772A1004, and C7772A1012  
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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  
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PS20 (535-34AB08-203) – Remote pipe sensor  
(
20K Ohm)  
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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.  
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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS  
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.  
62-0311—13  
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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.  
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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:  
•
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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  <