![background image](http://html.mh-extra.com/html/carrier/53dfs250-sl/53dfs250-sl_installation-instructions-manual_2564020003.webp)
Page 3
Advanced Setup Table
• TWO-STAGE OPERATION — The second stage of
heat (heat pump models only) is turned on when (
1
)
the first Stage has been on for a minimum of two
minutes,
and
(
2
) the temperature spread from the
set point is equal to or greater than:
the set point
temperature plus the deadband, plus 2 degrees.
• MINIMUM HEAT/COOL SET POINT DIFFERENCE
— The Heat and Cool set point temperature will not
be allowed to come any closer to each other than
the value set in Advanced Setup
Step 5, on page 2
.
This minimum difference is enforced during Auto
changeover and Program On operation.
• ENERGY SAVING SMART FAN — If Fan On is
selected, the fan will run continuously at all times,
except in Off,
and
will only run if there is a heating
or cooling demand in Unoccupied periods.
• OVERRIDE — Press the Override button during a
programmed, Unoccupied period to force the ther-
mostat into the Occupied 1 period, temporarily, up
to 4 hours. If the Override button is pressed during
an Occupied period, the thermostat will be forced
into the Unoccupied period and the occupied num-
ber
(1,2 or 3)
, it was forced out of will be turned off,
only for that day.
During Override periods the set point temperature
may be adjusted, but it will not be remembered after
Override ends.
• HEAT — First Stage = Heat Pump. Second Stage =
Heat Pump and Electric Heat.
• FAN PURGE TIMER — When this feature is acti-
vated, the fan will turn on during the Unoccupied
period at a preset amount of time prior to the Occu-
pied 1 period. This preoccupancy fan purge timer
may be set as instructed on
this page, Step 12
,
from 0 to 3 hours. 0 = this feature turned off.
• KEYPAD LOCK — To prevent unauthorized use of
the thermostat, the front panel buttons may be dis-
abled. To disable, or ‘lock’ the keypad, press and
hold in the Mode button. While holding the Mode
button in, press the Up and Down buttons in to-
gether. The
Locked
icon will appear on the display.
To
unlock
the buttons, again press and hold the
Mode button. While holding the Mode button in,
press the Up and Down buttons in together. The
Locked
icon will disappear from the display.
• DRY CONTACT SWITCH — The terminals are ‘nor-
mally open.’ Closing or completing the circuit will
cause the thermostat to enter the Occupied 1
period. This feature allows an external device such
as a central time clock, occupancy sensor, or a
telephone-activated device to force one or more
thermostats into the Occupied 1 period. For the dry
contact switch to work, the thermostat must be in
Program On
.
Set Occupied 1 to Off for all 7 days,
so the contact closure will be in control. When the
thermostat is forced into the Occupied 1 period via
the Dry Contact closure, the icon
Occupied 1
will
blink.
Advanced Setup (cont)
STEP
NO.
DESCRIPTION
RANGE
FACTORY
DEFAULT
1
Time of day clock set
24 hour
12:00 Am
2
Day of the week
Su - Sa
Mo
3
Heat Pump
Off / On
Off
4
Deadband or Temperature swing
1 - 6 F
2 F
5
Forced minimum difference heat/
cool
0 - 6 F
2 F
6
Cycles per hour
d, d1, 2 - 6
6
7
Security Levels
0 - 3
0
8
Maximum allowable Heat set point
35 - 99 F
80 F
9
Minimum allowable Cool set point
35 - 99 F
65 F
10
Fahrenheit or Celsius
F / C
F
11
Thermoglow™ backlight
Off / On
On
12
Fan Purge timer
0:00 - 3:00
min.
0:00 min.
13
Soft Start
0 - 99
0
About Advanced Features and Operation
IMPORTANT: For control of multiple thermostats by
one source, refer to Potential Phasing Problems (doc-
ument part no. 88-173) prior to installing.
=
to
F
Press the Mode button. While holding the Mode, press the Program button to
leave the Setup screens. If no buttons are pressed, the display will leave the
setup screens after 30 seconds.
Heat
Set Point
Cool
Set Point
1st Stage
turn on
1st Stage
turn on
1st Stage
Low
2nd Stage
turn on
2nd Stage
Med
Med
Heating
Cooling
3rd Stage
High
Dead
Band
Dead
Band
2 degrees
2 degrees
2 degrees
2 degrees
High
Low
Fan Speeds
Program On
Locked
unoccupied
ON
CK1
GND