Salus ST921WF User manual

ST921WF SOLO
2H/1C Wi-Fi Thermostat
Installation Manual
For other language versions, please visit: www.salusinc.com

i
Regulatory Statements
FCC
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this
device may not cause harmful interference, and (2) this device must accept any interference received, including
interference that may cause undesired operation.
Changes or modications to this unit not expressly approved by the party responsible for compliance could void
the user’s authority to operate the equipment.
NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to
Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference
in a residential installation. This equipment generates, uses and can radiate radio frequency energy, and if not
installed and used in accordance with the instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning the equipment o
and on, the user is encouraged to try to correct the interference by one or more of the following measures:
•Reorient or relocate the receiving antenna.
•Increase the separation between the equipment and receiver.
•Connect the equipment into an outlet on a circuit dierent from that to which the receiver is connected.
•Consult the dealer or an experienced radio/ TV technician for help.
FCC AND INDUSTRY CANADA
RF Radiation Exposure statement: This equipment complies with FCC and Industry Canada RF radiation exposure
limits set forth for an uncontrolled environment. This equipment should be installed and operated with a minimum
distance of 20 centimeters between the antenna and all persons.
Cet appareil est conforme aux limites d’exposition au rayonnement FR du FCC et d’Industrie Canada pour un
environnement non contrôlé. Cet appareil devrait être installé et devrait fonctionner de sorte qu’il se trouve à une
distance d’au moins 20 cm entre l’antenne et toute personne.
INDUSTRY CANADA
This device complies with Industry Canada license-exempt RSS standard(s). Operation is subject to the following
two conditions: (1) this device may not cause interference, and (2) this device must accept any interference,
including interference that may cause undesired operation of the device.
Le présent appareil est conforme aux CNR d’Industrie Canada applicables aux appareils radio exempts de licence.
L’exploitation est autorisée aux deux conditions suivantes : (1) l’appareil ne doit pas produire de brouillage, et (2)
l’utilisateur de l’appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible
d’en compromettre le fonctionnement.

ii
Safety Instructions
Please read these instructions carefully BEFORE INSTALLING AND USING
the ST921WF Thermostat. This manual is meant to be used as a reference guide
for the installation, conguration and maintenance of your device.
•Follow all regulations required by the local jurisdiction and electricity
supplier regarding the installation or replacement of a thermostat. An
authorized, qualied installer may be required.
• DO NOT CONNECT ANY TERMINALS TO 110 VAC or 220 VAC SUPPLY
VOLTAGE. The ST921WF Thermostat uses a 24 VAC power source.
• DO NOT expose the unit to voltage uctuations of more than ±10%.
• DO NOT cover any of the vents on the thermostat.
• DO NOT allow the unit to get wet. This device serves as a temperature
control system in dry, closed living and oce spaces.
• DO NOT place the thermostat in a bathroom or area of excessive moisture
where relative humidity exceeds 90%.
• DO NOT expose the thermostat to temperatures below -4°F (-20°C) or above
122°F (60°C).
• DO NOT install this unit in an altitude of over 6,500 feet (2,000 meters).
• DO NOT use solvents or aggressive cleaning agents. A soft dry cloth
is recommended.
The manufacturer accepts no responsibility for any damage caused by
failure to follow these instructions.

iii
Using this Manual
For the latest Instructions go to: WWW.SALUSINC.COM
Special Attention Boxes
This manual uses special attention icons to alert the reader of important safety
concerns, information important to reliable operation of the controls or helpful
installation/setup information.
Safety:
Indicates a condition which may cause severe
personal injury, death or major property damage
Important Information:
Indicates information which requires special
attention for correct operation of the control
Your Benet:
Indicates helpful installation or setup information

iv
Contents
REGULATORY STATEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
SAFETY INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
USING THIS MANUAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
IN THE BOX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
INSTALLING THE THERMOSTAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Turn O Power to HVAC System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Determine Wiring Conguration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Remove Old Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Install Mounting Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Attach Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Attach Display to Mounting Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Turn on Power to HVAC System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
DEVICE BOOT SEQUENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
MOBILE SETUP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
SCREEN DISPLAY & CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
SPECIFICATIONS/TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . 11
SALUS WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
APPENDIX A - WIRING DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

1
In The Box
ST921WF Thermostat
with Mounting Plate
Wall Plate (if required)
Mounting Screws & Anchors Installation Manual

2
Installing the Thermostat
There are ve steps to installing
the thermostat:
1. Determine Wiring Conguration
2. Remove Old Thermostat
3. Determine if Wall Plate is required
to cover opening, damage,
or discoloration of wall surface.
4. ST921WF Mounting Plate
5. Connect Wires
6. Attach Display
Tools
You may need the following tools to
install the ST921WF Thermostat:
• #1 Phillips or athead screwdriver
• Power drill with 3/16”bit (if new
mounting holes are required)
• Smartphone/camera to photograph
wiring for reference (optional)
• Screwdriver to disconnect wires
existing thermostat
• Pencil
Turn O Power to HVAC System
Locate the HVAC panel breaker and turn
OFF the system. Before removing the
old thermostat, change the temperature
setting to cause a heating or cooling
call. When the thermost indicates there
is a call, make sure the HVAC System is
not operating.

3
Determine Wiring Conguration
If the ST921WF Thermostat is being installed in a new system or if wiring
changes are intended, refer to Appendix A for the wiring congurations and
skip to Install Mounting Plate.
When replacing a thermostat and replicating the wiring of the existing
thermostat is desired on the ST921WF the following applies.
•Remove the old thermostat to expose the wiring terminals
•Photograph the wiring for reference or use the table below to note
the wire colors.
•Use the Wire Color Record to note the wire color and function of each
wire. If the terminals of the existing thermostat are unmarked,
determine the wire functions for each color wire at the appliance.

4
Wire Color Record
HP NON-HP Wire Color
RC RC
RH RH
C
G
Y1
O/B W1
L

5
Remove Old Thermostat
Remove the old thermostat from the wall, taking care not to allow the wiring
to fall inside the wall.
The ST921WF Thermostat IS NOT COMPATIBLE with supply
voltages above 30 VAC. If the old thermostat is connected with
thick wire and wire nuts or voltages higher than 30 VAC are noted
on the connections, DO NOT INSTALL the Thermostat.
Wrap wires around a pencil or similar object to
prevent them from falling into the wall void.

6
Install Mounting Plate (with Wall Plate, if required):
Use the included wall anchors and screws to attach the Mounting Plate to the
wall, making sure the wires run through the center opening.
To cover paint or screw holes on the wall behind the thermostat, insert the
Wall Plate between the Mounting Plate and the wall as shown. Both plates are
secured with the same screws.

7
Attach Wiring: To insert a wire into a terminal, ip up the locking tab and
slide the wire into the socket directly above the corresponding label. Insert
each wire as required for the desired appliance. Once each wire is inserted,
ip the tab down to lock it in position. Pull gently on each wire after locking
the tab is closed to be sure the wire is secure.
A factory supplied jumper is supplied between RC and RH.
This should be removed in two transformer systems
(see Appendix A, page 16).

8
Attach Display to Mounting Plate: Line up sockets in the back of the
thermostat with the posts on the wall plate and snap it into place.
Make sure the connector pins are not bent and wires do not interfere with
the thermostat engagement. The thermostat must be fully seated on the
wall plate to operate correctly.

9
Turn on Power to
the HVAC System Go to the furnace
switch or breaker box
and turn the HVAC
system back on.
When the ST921WF is rst powered or if a Factory Reset is performed, the above
boot sequence will be displayed. The last screen displays the thermostat model and
rmware version number.
Mobile Setup
When the text begins scrolling across the text eld,
the thermostat is ready to connect with the smart device application.
Device Boot Sequence
Download the SALUS SOLO application on your IOS or
Android device. After downloading the application, follow
the steps in the SALUS SOLO Mobile Application Guide at:
https://www.salusinc.com/downloads/

10
1Alphanumeric text display
2Schedule Override Indicator
Temporary: & Permanent: 9Fan indicator:
Auto - On -
3Setpoint or parameter value 10 Cooling Mode
4Setpoint indicator 11 O Mode
5Schedule running indicator 12 Auto Cooling/
Heating mode
6Fahrenheit or Celsius units 13 Heating Mode
7Room Temperature 14 Emergency Heat mode
8Wi-Fi indicator 15 Key lock indicator
Mode - Mode Selection Fan - Fan Speed Selection Increase Value
Decrease Value
Screen
Display
& Controls
7
6
5
4
3
2
1
9
15 8
14
13
12 11
10

11
Specications
Temperature units °C or °F
Environmental
Operating: 32° to 113°F (0° to 45°C)
5 to 90% Relative Humidity (non-condensing)
Storage: -4° to 122°F (-20° to 60°C)
5 to 90% Relative Humidity (non-condensing)
Communications 802.11 b/g/n, 2.4 GHz band
Bluetooth v4.2 BR/EDR and BLE (for Commissioning)
AC power 18-30 VAC at RC and C terminals
3 relay outputs rated for 1A @ 18-30 VAC
Dimensions 3.9” x 4.2” x 0.9”
10.0cm x10.6cm x 2.3cm
Weight 0.6 lbs (297 g)
Compliance FCC, Industry Canada
Warranty 5-year limited warranty
Compatible Devices SA918 Wire Extender Module
Note: Specications subject to change without notice.
Troubleshooting
For troubleshooting instructions go to: https://www.salusinc.com/downloads/

12
Salus Warranty
SALUS North America, Inc. (“Salus”) warrants that for a period of ve (5) years (“Warranty
Period”) from the date of purchase by the consumer (“Customer”), this device,
excluding batteries (“Product”), shall be free of defects in materials and workmanship
under normal use and service in accordance with all supplied instructions. During the
warranty period, Salus shall, at its option, repair or replace any defective Products, at
no charge for the device. Any replacement and/or repaired devices are warranted for
the remainder of the original Warranty Period or ninety (90) days, whichever is longer.
This warranty does not cover removal or reinstallation costs. This warranty does not
apply to any Product (i) which has been modied, repaired, or altered, except by Salus
or an authorized Salus representative, (ii) which has not been maintained in accordance
with any handling or operating instructions supplied by Salus, or (iii) which has been
subjected to unusual physical or electrical stress, misuses, abuse, negligence or accidents.
This warranty is the only express warranty Salus makes for the Product. Any implied
warranties, including warranties of merchantability or tness for a particular
purpose, are limited to the Warranty Period or the shortest period allowed by law.
SALUS SHALL NOT BE LIABLE FOR ANY LOSS OR DAMAGE OF ANY KIND,
INCLUDING ANY SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES
RESULTING, DIRECTLY OR INDIRECTLY, FROM ANY BREACH OF ANY
WARRANTY, EXPRESS OR IMPLIED, OR ANY OTHER FAILURE OF THIS PRODUCT.
Some states and provinces do not allow the exclusion or limitation of incidental
or consequential damages, or limitation on the duration of implied warranties of
merchantability or tness, so these exclusions or limitations may not apply to you.

13
Salus Warranty (continued)
No oralorwritteninformationoradvicegivenbySalusoraSalus-authorizedrepresentative
shall modify or extend this warranty. If any term is held to be illegal or unenforceable,
the legality or enforceability of the remaining terms shall not be aected or impaired.
Customer’s sole and exclusive remedy under this limited warranty is product repair or
replacement as provided herein.
If a Product under warranty is defective, the Customer may:
•Contact the party (“Seller”) from which the Customer purchased the Product
to obtain an equivalent replacement product after the Seller has determined
that the Product is defective and the Customer is eligible for a replacement, or,
•Contact Salus Service at [email protected], to determine whether the
device qualies for a replacement. If a replacement is warranted and is shipped
prior to the return of the device under warranty, a credit card is required and a hold
may be placed on the Customer’s credit card for the value of the replacement
until the returned device is veried as eligible for replacement, in which case, the
Customer’s credit card will not be charged. This warranty gives you specic legal
rights, and you may also have other rights that vary from jurisdiction to jurisdiction.
If you have any questions regarding this warranty, please write Salus at:
SALUS NA, Inc.
4700 Duke Drive
Suite 200
Mason, OH 45040-9507

14
Appendix A - Wiring Diagrams
ST921WF Thermostat Terminal Reference
Terminal Non-Heat Pump Heat Pump
RC 24 VAC Power – Cool
RH 24 VAC Power – Heat
C24 VAC Common
(Use SA918 Wire Extender if C-wire is not available)
GFan
Y1 Cooling Compressor
Not Used Not Used
W1/OB Heating Reversing Valve
Auxiliary Emergency Heat
L Not Used Check/Fault Input

15
Conventional Single Transformer Heat and Cool System: