Saswell T21STK-0 User manual

1
OPERATING
T21STK-0
INSTRUCTION

2
T21STK-0 SINGLE STAGE THERMOSTAT
1 Heat / 1 Cool single stage thermostat.
Non Programmable, Compatible with heat pump system
Installation and Operation Manual
Specification:-------------------------------------------------------------------------
Power Supply: 20VAC-30VAC 50-60HZ or Battery powered.
Terminal Load: 1.0A per terminal, 3.0A maximum total load
Set Point Temp. Range: 45ºF to 90ºF (7ºC to 32ºC).
Accuracy: +/- 1ºF or +/- 0.5ºC.
Dimensions: 6.0” W X 4.7” H X 1.1” D
Color: White

3
FEATURES:----------------------------------------------------------------------------
• Large LCD display with backlight, continuous backlight option.
• Simultaneous heat and cool set point storage.
• Display of room temperature, set temperature and current time
simultaneously.
• Fan switch with ON and AUTO functions.
• Permanent user setting retention during power loss. No batteries are
required.*
• Operates from 24VAC, or from 2 size “AA” alkaline batteries.
• Air Filter change Indicator.
• Low Battery Indicator.
• Temperature calibration.
• Batteries required to maintain clock function.

4
IMPORTANT SAFETY INFORMATION-----------------------------------------
• Always turn off power at the main power source by removing the fuse,
or switching the circuit breaker to the off position before installing,
removing, cleaning, or servicing this thermostat.
• Read all of the information in this manual before installing this
thermostat.
• Use a professional contractor to install this thermostat.
• This is a 24VAC low-voltage thermostat
DO NOT INSTALL ON VOLTAGES HIGHER THAN 30 VAC.
• ALL wiring must conform to local and national building and electrical
codes and ordinances.
• Do not short (jumper) across terminals on the gas valve or at the
system control to test installation. This will damage the thermostat and

5
void the warranty.
• Do not switch the system to cool if the temperature is below 50ºF
(10ºC). This may damage the air conditioning system.
• Replace batteries when the battery icon indicates the low battery
message.
• Change the Air Filter when the Filter Change Icon begins blinking.
• Use this thermostat only as described in this manual.
REMOVE THE OLD THERMOSTAT--------------------------------------------
WARNING ! Electrical Shock Hazard
1.Turn off power at the main service panel by removing the fuse or
switching the appropriate circuit breaker to the OFF position before
removing the existing thermostat.

6
2. Turn off power to the heating and cooling system by removing the
fuse or switching the appropriate circuit breaker off.
3. Remove the cover of the old thermostat. This should expose the
wires.
4. Label the existing wires from the existing thermostat before
removing.
5. After labeling the wires, remove the wires from the wire terminals.
6. Remove the existing thermostat from the wall
7. Refer to the following section for instructions on how to install this
thermostat.

7
INSTALL THE THERMOSTAT ----------------------------------------------
ATTACH THERMOSTAT BASE TO WALL PULL THE COVER OFF THE BASE.
Figure 1

8
WARNING！Electrical Shock Hazard
Turn off power at the main service panel by removing the fuse or
switching the appropriate circuit breaker to the OFF position before
removing the existing thermostat.
1. Turn off power to the heating and cooling system by removing the
fuse or switching the appropriate circuit breaker off.
2. Place the system switch (HEAT/OFF/COOL) in the OFF position.
3. Place the FAN (ON /AUTO) switch in the AUTO position.
4. Gently pull the cover straight off the base. (See figure 1.)
5. Put the thermostat base against the wall where you plan to mount it.
(Be sure the wires will feed through the wire opening in the base of the
thermostat.)

9
6. Mark the placement of the mounting holes.
7. Move the base out of the way. Drill mounting holes. Use a hammer
to tap in the supplied anchors into the mounting holes.
8. Fasten the base loosely to the wall as shown in Figure 1, using two
mounting screws. Place a level against the bottom of the base and
adjust until level, then tighten the screws. (Leveling is for appearance
only, and will not affect thermostat operation.)
9. Insert stripped, labeled wires into matching wire terminals. See
“Wiring Diagrams”, Figure 2.
CAUTION: Be sure exposed portions of wires do not touch other wires.
10. Tighten screws on terminal block. Gently tug on each wire to be
sure of proper connection. Double check that each wire is connected to
the proper terminal.

10
CAUTION: Installing batteries backwards can damage the thermostat.
11. Install two fresh “AA” alkaline batteries in the battery compartment.
Be sure to match positive (+) ends of batteries with positive (+) battery
terminals in the battery compartment. (The thermostat will operate
from 2 size “AA” alkaline batteries or 24VAC power. When operated
from 24VAC power, your thermostat will maintain time and
continuously display the temperature during a loss of AC power with
the batteries installed).
12. Replace the cover on the thermostat by snapping it in place.
13. Turn on power to the system at the main service panel.
14. Test thermostat operation as described in the following section.