RS PRO 908WHB-3 User manual

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908WHB-3/B is a programmable thermostat designed for water boiler and electric furnace
application. This thermostat can be used for hot water radiant heating and electric cable heating
system.
SPECIFICATION:
Power source …………………… 2 AA size 1.5V alkaline battery
Maximum resistive load……………… 230VAC 5A
Maximum inductive load………………230VAC 2A
Relay contact …………………………230VAC 8A
Room temperature setting range………5℃to 35℃(41℉to 95℉)
Accuracy……………………………. ±1℉or ±0.5℃
Dimensions………………………… 115mm×90mm×16mm
Color……………………………….. White
FEATURE:
zLarge LCD display
zThe screen displays the set temperature and the room temperature also time simultaneously
zPermanent user setting and program setting retention during power loss,
zOptional temperature display of Celsius or Fahrenheit scale
zBoth Vacation mold and hold duration mode available for comfort and energy saving
zSeparate 5-day (weekday) and 1-day/1-day (Saturday/Sunday programming with four separate
time/temperature periods per day.
zDisplay temperature recalibrates
zAnti-freezing protection
zPump protection available
IMPORTANT SAFETY INFORMATION:
zAlways turn off power at the main power source by unscrewing fuse or switching circuit
breaker to the off position before installing, removing, cleaning, or servicing this thermostat.
zRead all of the information in this manual before installing this thermostat.
zOnly a professional contractor should install this thermostat.
zAll wiring must conform to local and national building and electrical codes and ordinances.
zThis thermostat has a removable fuse to protect the system from damage. If system is not
operating properly, check wiring and replace fuse if necessary.
zUse this thermostat only as described in this manual.
KEYBOARD, DISPLAYAND SWITCH DESCRIOPTION
SAS908WHB-3/BThermostatforRadiantheating
Installation and operation instructions

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Figure1 Figure2
①Power on/ anti-freezing /off button
②Time setting button
③Program setting button
④Program run confirmation button
⑤Reset button
⑥Raise Temperature setting button
⑦Lower Temperature setting button
⑧Shows current day or days being programmed.
⑨Shows current time or times being programmed
⑩Am:: Morning ，Pm:: Afternoon Days: Nr of days，Hours: Nr of hours
⑪Shows temperature display in ℃or ℉
⑫Setting temperature
⑬Indicates a malfunction with the system.
⑭Low battery indicator
⑮Shows when thermostat is in the programming mode.
⑯Shows when thermostat is in the pump protection mode
⑰time to get up，time to go out time to come back home
time to go to bed
⑱Shows the thermostat is calling for heat
⑲Wait icon
⑳Set day/time: Shows current day and time being displayed
○
21 Prog setting: Shows when the thermostat is in program setting mode.
○
22 Cofg: Shows when the thermostat is in the configuration mode
○
23 Shows current system mode
○
24 Hold: Shows when thermostat is in the holding temperature mode
Vacation: Shows when thermostat is in the vacation mode.
○
25 Shows current room temperature.

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INSTALLTHE THERMOSTAT
ATTACH THERMOSTAT BASE TO WALL
Base
Screw for mounting thermostat to wall
Figure 3
Fixing screw
Control panel
1. Remove 2 screws from the bottom of thermostat.
Gently pull the control panel straight off the base.
Forcing or prying on the thermostat will cause
damage to the unit.
2. Connect wires beneath terminal screws on power
supply module using appropriate wiring
schematic. See figure 4
3. Push power base into wall.
4. Using two mounting screws mount the power
base to the wall. Place a level against bottom of
base, adjust until level, and then tighten screws.
(Leveling is for appearance only and will not
affect thermostat operation.)
5. Replace control panel on the power base and fix
power base and control panel by removed two
screws in item 1
WIRING DIAGRAM
123
230VAC
T2
T1
230VAC
3
2
1
250VAC 8A
Pump or valve
Relay
250VAC 8A
Figure 4
CHECK THERMOSTAT OPERATION
The unit will be controlled via air sensor in the thermostat and the thermostat will determine to
activate/deactivate heating system by comparing set temperature with room temperature. Press ▲to
adjust thermostat setting above room temperature 1℃in fast heating mode or 3℃in slow heating mode,

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See configuration menu item 5. The heating should begin to operate immediately
OPERATION
1. Configuration Menu
The configuration menu allows you to set certain thermostat operating characteristics to your system
or personal requirements. Shortly press button ①to make sure the thermostat is in anti-freeze mode.
Hold button ③for 3 seconds to enter the configuration menu. The display will show the first item in the
configuration menu. Press button ③to shift to the next menu item. Use ▲、▼to select. To exit the
menu , press button ①revert to the anti-freeze mode . Press button ④revert to the program operation.
If no buttons are pressed within 20 second the thermostat will exit the menu. To revert to factory default
setting , push ▲、▼ button in a same time for 3 seconds. Display will show “DEF” blinking 3 times and
return to Menu item 1 indicates all the configuration setting has reverted to factory default setting.
The configuration menu chart summarizes the configuration options. An explanation of each option as
follows:
Item Press buttons Displayed（factory default）Press▲、▼to select Descriptions
1 ③01 (0) -3 --- +3 Select temperature display adjustment
higher or lower
2 ③02 （35℃） 18℃(64℉)—35℃(95℉) Select maximum setting temperature
for heating
3 ③03 （5℃） 5℃(41℉)—20℃(68℉) Select minimum setting temperature
limitation
4 ③04 （℃） ℃/℉Select temperature display to℃or
℉
5 ③05 （FA）FA/SL Select fast heating or slow heating
6 ③06 （PP）PP/OO Select pump protection PP
Cancel pump protection OO
7 Press button ④revert to the program operation
1) Select temperature recalibrates Adjustment 3 LO to 3 HI –
You can adjust the room temperature display up to 3 higher or lower. Your thermostat was accurately
calibrated at the factory but you have the option to change the display temperature to match your previous
thermostat. The current or adjusted room temperature will be displayed on the right side of the display.
2) Select maximum temperature set point
This feature provides a maximum set point temperature f. The default setting is 35℃(95℉), It can
be changed between 18℃(64℉) to 35℃(95℉)
3) Select minimum temperature set point.
This feature provides a minimum set point temperature. The default setting is 5℃(41℉), It can be
changed between 5℃(41℉) to 20℃(68℉)
4) Select ℉or ℃readout.
Changes the display readout to Centigrade or Fahrenheit as required
5) Select fast heating or slow heating
Select FA to start heating immediately when the set point is 1℃above the room temperature. Select
SL to start heating only when the set point is 3 ℃above the room temperature.
6) Select pump protection mode

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For hot water installations, it is recommended to activate the pump at least 15 second every 24 hours
in order to avoid any seizing. Select PP will activate pump protection mode. Select OO will cancel the
function. When thermostat activating the pump, ○
15 in the display will blink.
2. Manual Operation
1) Anti-freezing mode
You can press power button ①to activate the anti-freezing mode. The unit only displays Clock time,
Weekday and Room temperature. The default set temperature for anti-freezing mode is 5℃. During
anti-freezing mode, if room temperature decrease to 5℃, the unit will activate the heating system till room
temperature reach to 9℃. For hot water installations, if PP had been selected (See Configuration menu
item 6), the unit will activate the pump at least 15 seconds every 24 hours in order to avoid any seizing.
Press power button ①again will terminate the anti-freezing mode and return to normal operation mode.
2) Program operation and Hold temperature operation
Momentarily press ④shift between program operation and hold temperature operation. Prog
running shows when thermostat is in program operation. Thermostat controls the heating system by
presetting program. See Planning your program section. Hold shows when thermostat is in hold
temperature operation. The thermostat will hold the room temperature at the selected setting
3) Temperature override
During program operation, Press ▲、▼ until the temperature you want is displayed. The thermostat will
override the current programming and keep the room temperature at the selected temperature until the next
program period begins. Then the thermostat will automatically revert to the program.
4) Vacation Temperature hold
Continue pressing button ③over 3 seconds until display will show Vacation indicates you have now
entered into vacation hold，Use time key ②or ③to select the number of the days (from 1 to 99 days)
during your vacation.，you can use ▲、▼to adjust the temperature during your holiday. Push button ④
to revert to program operation.。
5) Reset operation
If the display is abnormal, press the Reset button by using a fine probe such as a straightened paper
clip to gently push the Rest button. This will reset the thermostat.
3. Set current day and time
1) Press ②button. The display will show the hour flashing.
2) Press and hold either ▲、▼ until you reach the correct hour and AM/PM designation.(AM begins at
night, PM begins at noon)
3) Press ②button once again. The display will only show minutes flashing
4) Press and hold either ▲、▼ until you reach the correct minutes
5) Press ②button once again. The display will show the day of the week flashing.
6) Press ▲、▼ until you reach the correct day of the week
Press button ④once. The display will show the correct day of the week and the time. If no keys
are pressed within 20 seconds, the thermostat will revert to program operation.
4．Planning your program
Look at the factory preprogrammed times and temperatures shown in the sample schedule. If this
program will suit your needs, simply press the ④button to begin running the factory preset program.

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If you want to change the preprogrammed time and temperature, follow these steps.
Determine the times period and temperature for your program. You must program four periods for
each day. You can choose heating temperature and start time independently. (for example, you may select
5:00 AM and 70℉as the weekday 1st period heating start time and temperature and also choose 7:00 AM
and 76℉and the weekday 1st period cooling start time and temperature)
Use the table to plan your program time periods and the temperatures you want during each period. Fill in
the complete table to have a record of your program
Heating Schedule Plan (Factory default program setting)
Weekdays (5 day) Saturday Sunday
Period
Start time Temperature Start time Temperature Start time Temperature
6:00 AM 21°℃6:00 AM 21°℃6:00 AM 21°℃
8:00 AM 16.5℃8:00 AM 16.5℃8:00 AM 16.5℃
5:00 PM 21°℃5:00 PM 21°℃5:00 PM 21°℃
Heat
10:00 PM 16.5℃10:00 PM 16.5℃10:00 PM 16.5℃
Enter Heating Program
1). Press ③once. PRGM SETTING will display. “MO TU WE TH FR” (indicating weekday
program) will appear in the display. Also be displayed are the currently programmed start times for the
1st heating period and the currently programmed temperature (flashing), icon indicates 1st
program period (Get up) setting。
2). Press ②to set the programmed time or programmed temperature ，Press ②once (the
programmed temperature will flash) ，Press ▲、▼ to change the displayed temperature to your
selected temperature for the 1st heating program period.
3). Press ②once (the programmed time will flash). Press ▲、▼ until your selected time appears.
The time will change in 15-minute increments. When your selected time is displayed, press TIME
again to return to the change temperature mode.。
4). Press ③once，icon 2nd program period（Go out）display，he currently programmed
start time and set point temperature for the 2nd heating program period will appear
5). Repeat steps 3 and 4 to select the start time and heating temperature for the 2nd heating program
period.
6). Repeat steps 3 through 5 for the 3rd and 4th heating program periods
7). Press ③once. “SA” (indicating Saturday program) will appear in the display, along with the
start time for the 1st heating period and the currently programmed temperature.
8). Repeat steps 3 through 7 to complete Saturday heating programming.
9). Press ③once to change to SU (Sunday) heating programming and repeat steps 3 through 7 to
complete Sunday programming.
10). When you have completed entering your heating program, press ④.

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REVERT TO FACTORY DEFAULT PROGRAM SETTING
Press ③button enter into program setting. Press ▲、▼ at the same time for 3 seconds. Display will
show DEF blinking for 3 times and back to program setting. Press the ④button to begin running the
factory preset program. If no keys are pressed within 20 sec, the thermostat will revert to program
operation.
CHECK YOUR PROGRAMMING
Follow these steps to check your thermostat programming one final time before beginning thermostat
operation.
1. Press button ③to view the 1st weekday heating period time and temperature. Each time you press
button ③, the next heating period time and temperature will be displayed in sequence for weekday,
then Saturday and Sunday program periods (you may change any time or temperature during this
procedure).
Press button ④to begin program operation.
CUSTOMER ASSISTANCE
After reading this guide, if you have any question about the operation of your thermostat, please contact
your installer or Energy Utility company or service provider.

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