16
Air Filter
If
AIR FILTER
or
AIR PURIFIER
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: COOLING AIRFLOW and
DEHUMIDIFY.
COOLING AIRFLOW: Setting this to
COMFORT
or
QUIET
will enable the system to use low airflow to help dehumidify the
space. If duct sweating becomes an issue, setting DEHUM
AIRFLOW to
HIGH
may resolve the problem.
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 (2
_
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 (2
_
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 Cooling 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 Cooling
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.
If the room temperature falls below 40
_
F (4
_
C) and a furnace
lockout is in enabled, the furnace lockout will be overridden to
bring on the furnace.
UID
01
--
V
