Table of Contents
Advertisement
®
THX9321 PRESTIGE
2.0 AND THX9421 PRESTIGE
Advanced Features
ADAPTIVE INTELLIGENT RECOVERY (RESIDENTIAL
USE ONLY)
Over time, the Prestige® thermostat "learns" how long it
takes your system to reach your programmed temperature
setting.
The thermostat turns on the heating/cooling system early
and assures that the programmed temperature setting is
reached at the programmed time regardless of weather
conditions. For example, if the Wake program period is set
to 6:00 am with a heat setting of 70 degrees, the heat will
turn on before 6:00 am, so the temperature is 70 degrees
at 6:00 am. The thermostat displays "In Recovery" when it
turns the system on early.
Adaptive Intelligent Recovery® calculates the recovery
ramp based on how far the room temperature is away from
the temperature setting, previous equipment performance
and weather history, allowing the thermostat to start
recovery at the optimal time so it can reach the
programmed temperature setting at the programmed
time.
The Prestige® thermostat uses two recovery ramps when
setup to control a heat pump system. One ramp for the
compressor and one ramp for the auxiliary heat. Once the
room temperature intersects the compressor ramp, the
compressor turns on until the setpoint is reached. If the
room temperature does not rise quickly enough and
intersects the second ramp, the auxiliary heat turns on. It
takes about one week for the thermostat to adjust to
weather conditions, equipment performance and
construction of the home. If the temperature setting is
reached too early or too late, the ramp is adjusted for the
next day's recovery. See Fig. 143.
Fig. 143.
DEHUMIDIFICATION AWAY MODE
Your system can be set to control indoor climate while
your home is vacant during the humid season. Before you
leave, touch MENU, then select Dehumidification Away
Mode. Temperature and humidity will be kept at levels that
protect your home and possessions. When you return,
touch Cancel to resume normal operation.
68-0311—07
®
IAQ WITH EIM
COMPRESSOR SETPOINT
AUXILIARY HEAT SETPOINT
ROOM TEMPERATURE
WAKE
M6406A
COMPRESSOR PROTECTION
The thermostat keeps the compressor off for a few
minutes before restarting, to prevent equipment damage.
During this "off" time, the message "waiting for
equipment" is displayed on screen.
PRE-OCCUPANCY PURGE (COMMERCIAL USE ONLY)
This feature turns on the fan 1 to 3 hours before each
"occupied" time period, to provide a comfortable
workplace when you arrive.
P + I CONTROL
A conventional mechanical or electronic thermostat does
not control temperature precisely at setpoint. Typically
there is an offset (droop) in the control point as the system
load changes. Many factors contribute to offset including
the switch differential, thermal lag, overshoot, cycle rates
and system load.
The Prestige® thermostat however, works much differently
than a conventional mechanical or electronic thermostat.
The proprietary algorithm in the thermostat eliminates the
factors causing offset (droop). This makes temperature
control more accurate than the conventional mechanical
or electronic thermostat. The temperature control
algorithm is called proportional plus integral (P + I)
control.
The thermostat sensor or a remote indoor sensor senses
the current space temperature. The proportional error is
calculated by comparing the sensed temperature to the
setpoint temperature. The deviation from the setpoint is
the proportional error.
The thermostat also determines integral error, which is a
deviation based on the length of error time (how long the
sensed room temperature has been away from the
setpoint temperature). The sum of the two errors is the (P +
I) error. The cycle rate used to reach and maintain the
setpoint temperature is computed using the P + I control
algorithm. The addition of the integral error is what
differentiates the thermostat from many other mechanical
and electronic thermostats. See Fig. 144.
P+I CONTROL
POINT
THERMOSTAT
HEAT SETPOINT
HEATING
100
84
THERMOSTAT
COOL SETPOINT
PROPORTIONAL COOL
CONTROL POINT
P+I CONTROL POINT
PROPORTIONAL HEAT
CONTROL POINT
COOLING
50
0
50
PERCENT LOAD
Fig. 144.
100
M4414
Advertisement
Table of Contents
