15
Three--Minute Minimum On Time
In normal operation, when a stage turns on, it will remain on for a
minimum of three minutes. If the setpoint is changed, this timer is
automatically cancelled, allowing the equipment to turn off
immediately when the demand is removed.
Heat/Cool setpoints (Desired Temperatures)
A minimum difference of 2
_
F / 1.1
_
C (default) is enforced
between heating and cooling desired temperatures. This is done by
allowing one setting to “push” the other to maintain this difference.
This difference is adjustable via the Install/Service menu under
Thermostat Setup.
Temperature Display
The actual temperature displayed is always rounded toward the
setpoint. This is because the system is operating and measuring the
temperature in sixteenths of a degree, but displaying in whole
numbers. The system may be turned off and on within .5
_
F / .3
_
C
of setpoint, but the display may not change. This is by design and
does not indicate a problem with the control.
Auto Changeover
When Auto mode is enabled (factory default) a change from heat
to cool (or vice versa) will not occur until an opposite mode
demand has existed for 30 minutes. If the setpoint is changed, the
30--minute requirement is defeated. This Auto Changeover time is
adjustable via the Install/Service menu under Thermostat Setup.
Range = 5 -- 120 min.
Smart Recovery
With Smart Recovery selected (factory default), transition out of
setback begins 1.5 hours before selected recovery time and
gradually adjusts room temperature so desired temperature will be
achieved at selected recovery time. It operates in both heating and
cooling. This only applies to programmable operation.
For example: Set back temperature in heating is 64
_
F. Smart
Recovery setpoint is 70
_
F at 7:00 a.m. At 5:30 a.m., the control
calculates the required temperature recovery rate (recovery temp --
set back temp or current temp if greater) / 90 minutes. If the current
temp at 5:30 = 66
_
F, the recovery rate = (70 -- 66)
_
F/90 minutes =
0.04
_
per minute. In order to achieve setpoint, the control ramps up
the setpoint 0.04
_
F / minute from 5:30 a.m. until 7:00 a.m.
NOTE
: Temperatures should not be set back so far that the
equipment cannot recover in 90 minutes.
Media Filter
If
MEDIA
or
MEDIA+EAC
is installed in the indoor unit, the
system will perform a static pressure check of the system every 24
hours at 1:00 p.m. to monitor filter accumulation (TrueSense
t
Dirty Filter Detection) or whenever power is applied to the system
or the system is transitioned from Off to Cool or Heat modes. The
blower will run at a medium airflow for one minute.
This system operates by setting a base line static pressure based on
the highest airflow the system could run (this could be heat or cool
airflow.) The measurement is taken at a low airflow and then
calculated up to the highest airflow the system could see.
Frozen Coil Detection
During cooling operation, the User Interface will monitor the static
pressure of the system. If the static pressure is increasing
dramatically, the User Interface will turn off cooling for up to one
hour, record fault in the “Last 10 Events” screen, and run the fan at
a reduced airflow. The User Interface will continue to monitor the
static pressure. If it is reduced before one hour has elapsed, it will
resume cooling operation. After one hour, cooling will be resumed.
Dehumidify Operation
Once a target cooling humidity setpoint is selected in the Advanced
Setup COOLING HUMIDITY screen, two other setup options
affect Dehumidify operation: AC AIRFLOW and DEHUMIDIFY.
AC AIRFLOW: This setting is located in the Furnace or Fan Coil
Setup screens and must be set to
COMFORT
to enable normal
dehumidify operation. If set to EFFICIENCY or MAXIMUM, no
special dehumidify operation will take place during a normal
cooling call. Cooling will only operate to satisfy the space
temperature setpoint.
DEHUMIDIFY: Located in the Cooling Humidity screen of the
Advanced Setup, this option has 2 settings:
ON
and
OFF
.
If DEHUMIDIFY is set to
ON
(factory default), then the cooling
unit will be allowed to overcool the space up to 3
_
F / 1.7
_
C if the
humidity level is above the cooling humidity target setpoint.
The amount of over--cooling allowed varies with the
dehumidification demand, the cooling demand, and the actual
space temperature. More over--cooling is allowed with greater
dehumidification demand.
When the space temperature is at or above 75
_
F / 24
_
C and the
dehumidify demand is high, over--cooling up to 3
_
F / 1.7
_
C
is
allowed. As the space temperature approaches 70
_
F / 21
_
C, less
over--cooling is allowed. At 70
_
F / 21
_
C space temperature, no
more over--cooling is allowed no matter how great the dehumidify
demand. This is done to protect the equipment.
If DEHUMIDIFY is set to
OFF
and AC Airflow is set to
COMFORT
, normal dehumidification mode is enabled. For
normal dehumidification, no over--cooling is allowed when the
cooling humidity is above the target setpoint, but airflow will be
reduced during a normal cooling mode to reduce humidity. The
airflow depends on the amount of dehumidify demand. If AC
Airflow is set to
EFFICIENCY
or
MAXIMUM
, only
Dehumidify (over--cooling to dehumidify) will be performed.
Hybrid Heat Setup / Operation
Furnace Lockout
—
(
in HYBRID HEAT SETUP menu) is the
outside temperature above which the furnace will not run except
for defrost (otherwise known as the aux heat lockout).
Heat Pump Lockout
— (in HYBRID HEAT SETUP) is the
outside temperature below which the heat pump will not run
(otherwise known as the balance point).
These values can be set identical to each other. If they are not
identical, the system will stage up and down normally from heat
pump to furnace when the outside temperature is between these
settings. The User Interface will not allow the heat pump lockout
setting to be above the furnace lockout setting.
The factory default settings for both of these is NONE (no
lockouts). Even though a heat pump lockout temperature may be
set, the system will still use the furnace in defrost operation, and
may stage back down to heat pump when defrost is completed after
a 2 minute delay.
Hybrid Heat Defrost
— (in HYBRID HEAT SETUP) When the
outdoor unit needs a defrost cycle, the furnace will run during
defrost regardless of lockout temperature, unless told not to in the
Hybrid Heat Setup screen. After defrost, the system may stage
down to heat pump after a 2 minute delay.
CCUI
D
01
--
B
