Carrier 33CS250 FS Thermostat User Manual


Flush-Mounted Flatstat  
Commercial Programmable Thermostat  
Owner’s Manual  
Part Number 33CS250-FS and 33CS220-FS  
lower the desired set point, change the mode, program, and  
IMPORTANT: Read entire instructions before program-  
ming the thermostat.  
override the current program. See Fig. 2.  
ARROW buttons will raise or lower the current desired tem-  
perature set point. If the thermostat is in the AUTO or Program  
mode, pressing the UP ARROW or DOWN ARROW button  
will adjust both the heating and cooling set points. Pressing the  
UP ARROW or DOWN ARROW button in Cooling mode  
will adjust only the cooling set points. Pressing the UP AR-  
ROW or DOWN ARROW buttons in Heating mode will ad-  
just only the heating set points.  
OVERRIDE BUTTON — The Override button is used to  
force the thermostat from Unoccupied mode into the Occu-  
pied 1 mode comfort settings. The Override period will be set  
at 30 minutes. The thermostat will then return to the program  
for that time period. To increase the amount of time in Override  
mode, press the Override button again. Thirty minutes of over-  
ride time will be added for each time the Override button is  
pressed, up to a maximum of 4 hours. After the 4-hour limit  
has been reached, press the Override button again to cancel  
Override mode.  
Carrier’s 7-day, commercial, programmable thermostats are  
flat, wall-mounted, low-voltage thermostats which maintain  
room temperature by controlling the operation of an HVAC  
Heating, Ventilation and Air Conditioning) system. Separate  
heating and cooling set points and auto-changeover capability  
allow occupied and unoccupied programming schedules for  
energy savings.  
All thermostats allow up to 3 occupied and one unoccupied  
time/temperature settings to be programmed per 24-hour peri-  
od. Each thermostat stores programs for 7 independent days.  
Batteries are not required. During power interruption the inter-  
nal NEVERLOST™ memory stores programmed schedules  
for an unlimited amount of time.  
IMPORTANT: The thermostat has a configurable  
security level. If certain functions are not available  
While in Override mode, the Override icon and the Occu-  
pied 1 icon will be displayed on the thermostat. The time of  
day and the minutes remaining in Override mode will alternate  
on the thermostat display.  
The set points are adjustable with the UP ARROW and  
DOWN ARROW keys during Override mode.  
changing set points, changing programming sched-  
ules), the thermostat security level may be config-  
ured to exclude those functions. Call the installer to  
reconfigure the security level.  
NOTE: If the thermostat is in Occupied mode and the Override  
button is pressed, the thermostat will go into Unoccupied mode  
immediately. The thermostat will remain in Unoccupied mode  
until the next Occupied start time.  
Thermostat Display — The thermostat display is locat-  
ed in the center of the thermostat. See Fig. 1. The following in-  
formation can be displayed on the screen:  
fan setting (FAN ON or blank for Fan Auto operation)  
override indication  
room temperature  
desired temperature  
service filter indicator  
time of day  
day of the week  
schedule period (Occupied 1, 2, or 3; or Unoccupied)  
setup indicator (Programming mode)  
lock indicator  
start/stop indicator (schedule period program mode)  
Heat or Cool Indicator — A Heat or Cool indicator is  
located in the middle of the thermostat. See Fig. 2. The light  
will be red if the thermostat is in Heating mode. The light will  
be green if the thermostat is in Cooling mode.  
Thermostat Front Panel Buttons — The thermo-  
Fig. 1 — Thermostat Display  
stat has buttons on the front cover which are used to raise or  
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.  
PC 111 Catalog No. 533-353 Printed in U.S.A. Form 33CS-13SO Pg 1 105 11-00 Replaces: New  
Book 1  
Tab 11a 13a  
To scroll through by hours instead of minutes, hold down the  
Override button while pressing UP ARROW or DOWN AR-  
ROW. To ensure the schedules are properly followed, make  
sure that AM or PM is correct for the time chosen. When the  
correct time is shown, press the Mode button to modify the day  
of the week. The current day will blink on and off. Press the UP  
ARROW or DOWN ARROW button until the correct day is  
shown. Press and hold the Mode and Override buttons at the  
same time again to exit the Set Clock mode.  
Program Thermostat Schedules — Before pro-  
gramming the thermostat, plan the thermostat daily schedule.  
The schedule is divided into 7 days (Monday through Sunday).  
Each day has from 2 to 4 time periods (Occupied 1, Occu-  
pied 2, Occupied 3, Unoccupied) depending on the configura-  
tion of the thermostat. Each occupied time period has a start  
time, stop time, heating set point, and cooling set point. The un-  
occupied time period has a heating set point and a cooling set  
point. The unoccupied time period is active whenever an occu-  
pied time period is not active. Fill in Table 1 as an aid to pro-  
gramming the daily schedules.  
PROGRAMMING MODE — To program the daily sched-  
ules, perform the following procedure:  
. Enter Programming mode by pressing and holding the  
Mode and UP ARROW buttons. The Occupied 1  
annunciator will appear on the thermostat display. Use  
the UP ARROW or DOWN ARROW button to set the  
maximum number of Occupied periods for each day.  
The thermostat can be set to 1, 2, or 3. After the num-  
ber of Occupied periods has been selected, press the  
Mode button. See Fig. 3.  
Fig. 2 — Thermostat Front Panel  
MODE BUTTON — The Mode button selects the operating  
mode of the thermostat.  
If OFF is selected, the thermostat will not enter Heating  
or Cooling mode.  
If HEAT is selected, the thermostat will only enter Heat-  
ing mode (if the room temperature is below the heating  
set point). The thermostat will not provide cooling.  
If COOL is selected, the thermostat will only enter Cool-  
ing mode (if the room temperature is above the cooling  
set point). The thermostat will not provide heating.  
If AUTO is selected, the thermostat will enter Heating or  
Cooling mode based on the room temperature and the  
heating and cooling set points. The thermostat will pro-  
vide automatic changeover from Heating to Cooling  
mode and Cooling to Heating mode when required. The  
thermostat will automatically switch to maintain the  
desired temperature setting. The thermostat does not  
need to be manually changed from heating or cooling or  
cooling to heating operation.  
Fig. 3 — Setting Occupied 1 Set Points  
. The cooling set point for Occupied 1 will be displayed.  
Use the UP ARROW or DOWN ARROW button to raise  
or lower the cooling set point until the desired temperature  
is shown. The range of acceptable values is 35 to 99 F  
If PROGRAM ON is selected, the thermostat will oper-  
ate as in the AUTO mode (see above). PROGRAM ON  
enables the thermostat to follow the programmed daily  
schedule stored in its memory.  
(1 to 37 C). Press the Mode button to continue. See Fig. 3.  
Keypad Lock — To prevent unauthorized use of the ther-  
mostat, the front panel buttons can be disabled. To disable or  
lock the keypad, press and hold the Mode button. While hold-  
ing down the Mode button, press the UP and DOWN ARROW  
buttons simultaneously. The “Locked” icon will appear on the  
The thermostat is unlocked by performing the same proce-  
dure. Press and hold the Mode button. While holding down the  
Mode button, Press the UP and DOWN ARROW buttons  
simultaneously. The “Locked” icon will be removed from the  
3. The heating set point for Occupied 1 will be displayed.  
Use the UP ARROW or DOWN ARROW button to raise  
or lower the heating set point until the desired temperature  
is shown. The range of acceptable values is 35 to 99 F  
(1 to 37 C). Press the Mode button to continue. See Fig. 3.  
. The cooling set point for Unoccupied will be displayed.  
Use the UP ARROW or DOWN ARROW button to raise  
or lower the cooling set point until the desired tempera-  
ture is shown. The range of acceptable values is 35 to  
99 F (1 to 37 C) or ‘‘OF’’ (no unoccupied cooling). To  
configure the Unoccupied Cooling set point to OF, press  
the UP ARROW button until 99 F is displayed. Press the  
UP ARROW button again to display OF. Press the Mode  
button to continue.  
Set Clock — The Set Clock function allows the user to  
change the time and day displayed on the thermostat. Press and  
hold the Mode and Override buttons at the same time until the  
display changes. The display will show the setup annunciator.  
The current time will blink on and off. Press the UP ARROW  
or DOWN ARROW button until the correct time is shown.  
Hold down the buttons to quickly move through the time dis-  
play. The AM and PM annunciators will automatically change.  
. The heating set point for Unoccupied will be displayed.  
Use the UP ARROW or DOWN ARROW button to raise  
or lower the heating set point until the desired tempera-  
ture is shown. The range of acceptable values is 35 to  
99 F (1 to 37 C) or ‘‘OF’’ (no unoccupied heating). To  
configure the Unoccupied Heating set point to OF, press  
the DOWN ARROW button until 35 F is displayed. Press  
the DOWN ARROW button again to display OF. Press  
the Mode button to continue.  
. The day of the week will be shown. Use the UP ARROW  
or DOWN ARROW button to change the day of the  
week until the desired starting day is shown. Possible  
choices are Mo (Monday) through Su (Sunday). Press the  
Mode button when the desired day is shown.  
. The Start Time for Occupied 1 will be displayed. Use the  
UP ARROW or DOWN ARROW button to raise or low-  
er the time until the desired Start Time is shown. Press the  
Mode button to continue. See Fig. 4.  
. The Stop Time for Occupied 1 will be displayed. Use the  
UP ARROW or DOWN ARROW button to raise or low-  
er the time until the desired Stop Time is shown. Press the  
Mode button to continue.  
If only one occupied schedule is selected, the Occupied 2  
and 3 schedules are skipped. If the start time is set later in the  
day than the stop time, the program will run from midnight of  
that day to the stop time and then from the start time to mid-  
night. If the same start and stop times are programmed for an  
occupancy schedule, the thermostat will be in Occupied mode  
for 24 hours. If one occupied period starts or stops within an-  
other occupied period, the lower numbered schedule has priori-  
ty. For example, if schedule Occupied 3 is running for 24 hours  
and Occupied 2 schedule comes on from 1 to 3 PM, the set  
points from Occupied 2 are in effect from 1 to 3 PM.  
OVERRIDING THE SCHEDULE — The schedule can be  
overridden by pressing the UP or DOWN ARROW button to  
change the desired temperature. The thermostat will use the  
new set point until the next scheduled time period starts.  
. The On/Off icon will be displayed. Use the UP ARROW  
to turn the Occupied 1 period ON for this day. Use the  
DOWN ARROW to turn the Occupied 1 period OFF for  
this day.  
10. If more than one occupied period has been selected in  
Step 1, repeat Steps 2 through 9 to program the remaining  
schedule for Occupied periods 2 and 3.  
1. The Copy command can be used to copy the previous  
day’s schedule if the schedules are the same. The copy  
command becomes available after all the occupied peri-  
ods are programmed in a day. Use the UP ARROW to  
change the copy command to YES. Use the DOWN  
ARROW to change the copy command to NO. Press the  
Mode button when the choice has been made. See Fig. 5.  
Fig. 4 — Start Time Display  
If NO was selected, the schedule will automatically  
change to the next day and the user must enter the  
occupied and unoccupied schedules for that day.  
NOTE: Occupied 1 schedule heating and cooling set  
points are the same for each day. Occupied 2 and 3 set  
points may be set to different values for each day of  
the week.  
If YES was selected, the schedule will be copied to the  
next day. The schedule copy may be repeated until  
Sunday is reached. The Sunday schedule cannot be  
copied to Monday.  
2. After all the times and set points for each day have been  
entered, press and hold the Mode and UP ARROW  
buttons to exit Programming mode.  
Fig. 5 — Copy Command Display  
NOTE: The thermostat will continue to follow the schedule  
until a new one is entered.  
Table 1 — Daily Schedule Planner  
Occupied 1  
Start / Stop / Heat / Cool  
Occupied 2  
Start / Stop / Heat / Cool  
Occupied 3  
Start / Stop / Heat / Cool  
Start / Stop / Heat / Cool  
NOTE: The cooling temperature set point must be higher than the heating temperature set point.  
Holiday Mode — When the thermostat is in Holiday  
mode, the thermostat will operate under Unoccupied set points.  
To configure and activate the Holiday mode, press the Mode  
and UP ARROW buttons simultaneously to enter Program-  
ming mode. Press the Override button to enter Holiday Pro-  
gramming mode. The ‘‘HOL’’ icon will be displayed along  
with the remaining days of Holiday mode operation. Press the  
UP or DOWN ARROWS to select the number of days that the  
holiday schedule will be in effect. A value of 0 disables Holi-  
day mode. The duration can be set from 1 to 99 days. The ther-  
mostat will enter Holiday mode on midnight of the next day  
after the mode has been activated. Holiday mode will remain in  
effect until midnight of the last configured day.  
If the Holiday mode is in effect, the number of days remain-  
ing will blink on and off and the ‘‘Unoccupied’’ icon will be  
displayed. The Override button will be active during Holiday  
mode. The Dry Contact Switch is ignored.  
To turn off the Holiday mode before the remaining config-  
ured days have passed, press the Mode and UP ARROW  
buttons simultaneously for 2 seconds to enter Programming  
Mode. Press the Override button to enter Holiday Program-  
ming mode. Press the DOWN ARROW to set the number of  
days to zero. Holiday mode will be disabled.  
The Mode button selects the operating mode of the thermo-  
stat. If OFF is selected, the thermostat will not enter Heating or  
Cooling mode. If HEAT is selected, the thermostat will only  
enter Heating mode (if the room temperature is below the heat-  
ing set point). If COOL is selected, the thermostat will only en-  
ter Cooling mode (if the room temperature is above the cooling  
set point). If AUTO is selected, the thermostat will enter Heat-  
ing or Cooling mode based on the room temperature and the  
heating and cooling set points. If PROGRAM ON is selected,  
the thermostat will operate as in the AUTO mode and the  
stored schedule is enabled. The thermostat will follow the  
Occupied and Unoccupied schedules stored in its memory.  
Auto-Changeover — When the thermostat mode is set  
to AUTO, the thermostat will provide automatic changeover  
from Heating to Cooling mode and Cooling to Heating mode  
when required. The thermostat will automatically switch to  
maintain the desired temperature setting. The thermostat does  
not need to be manually changed from heating to cooling or  
cooling to heating operation.  
Two-Stage Operation — The second stage of heat or  
cool is turned on when the first stage has been on for a mini-  
mum of 2 minutes and the temperature differential from the set  
point is equal to or greater than the set point plus the deadband  
plus 2 degrees.  
Dry Contact Switch (33CS250-FS Only) — A dry  
contact switch is provided to allow an external device to force  
the thermostat into Occupied 1 mode. When the thermostat is  
forced into Occupied 1 mode via the dry contact closure, the  
Occupied 1 icon will blink each second.  
SOFT START — When multiple thermostats are controlled  
by the same external device, a Soft Start option can be used to  
stagger the turn on times of the HVAC equipment. This feature  
may cause a delay in operation after entering Occupied 1  
Clock Backup — In the event of a power loss, the ther-  
mostat will keep time for a minimum of 48 hours without  
external power or batteries.  
Fan Operation — If Fan On is selected, the fan will run  
continuously during occupied schedules (except when Mode is  
switched to OFF). The fan will be off during the unoccupied  
schedule except during heating or cooling operation.  
Remote Temperature Sensor (33CS250-FS  
Only) — A remote temperature sensor is available to read  
the temperature from a space. If a remote temperature sensor is  
connected and the thermostat is configured to use a remote  
temperature sensor, then the thermostat will ignore the reading  
of its internal sensor and control to the reading of the remote  
temperature sensor. When the thermostat is using a reading  
from a remote sensor, the degree symbol above the temperature  
reading will blink.  
If Fan On is not selected, the fan will only operate during  
heating or cooling operation.  
Emergency Heat — Emergency heat is available for  
heat pump applications. To turn on emergency heat, press and  
hold the Override button. While holding the Override button,  
press the UP ARROW button. An ‘‘EH’’ will be displayed.  
During emergency heat, the fan will operate and the second  
stage of heat will be energized (locking out the first stage com-  
pressor). To exit emergency heat, press and hold the Override  
button. While holding the Override button, press the UP  
ARROW button. During emergency heat, only OFF and HEAT  
modes are available.  
NOTE: This feature is configured by the installer.  
 Outside Temperature Sensor (33CS250-FS  
Only) — An optional outside temperature sensor may be pro-  
vided to sense outdoor-air temperature. Press and hold the  
Mode button for 5 seconds to display outdoor-air temperature.  
The “outside” temperature annunciator will be displayed. Press  
the Mode button again to exit the Outside Temperature display.  
Electric Heat — When the Electric Heat option in the  
advanced set up is set to ON (configured by installer), the  
thermostat will turn on the fan immediately any time there is a  
heat demand. This feature should only be used on electric heat-  
ing applications. Do not use with gas heat.  
Copyright 2000 Carrier Corporation  
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.  
Book 1  
PC 111 Catalog No. 533-353 Printed in U.S.A. Form 33CS-13SO Pg 8 105 11-00 Replaces: New  
Tab 11a 13a  

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