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4. Dehumidify Off — This is used to disable the dehumidify
mode. To turn this function OFF, use UP button to scroll the
set point all the way up. The highest setting will be 90
percent before off (OF) appears in the display. When OF is
displayed, the dehumidification mode is disabled (the
DHUM relay will remain on).
To exit humidity setup mode, press END button, or if no buttons
are pressed for 3 minutes, the User Interface will save and exit this
mode returning to normal operation.
OPERATIONAL INFORMATION
FIVE-MINUTE COMPRESSOR TIMEGUARD
This timer prevents the compressor from starting unless it has been
off for at least 5 minutes. It can be defeated for 1 cycle by
simultaneously pressing the FAN mode button and the UP button.
It is not active in the installer setup mode.
FIFTEEN-MINUTE CYCLE TIMER
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This timer prevents the start of the next cycle until at least 15
minutes after the start of the present cycle. Its job is to assure that
equipment is not cycled more than 4 times per hour (or 1 cycle
every 15 minutes). It is defeated for 1 cycle when the desired set
point is manually changed to provide fast response to set point
change. It can also be defeated for 1 cycle by simultaneously
pressing the FAN mode and UP buttons.
STAGING TIMER
In multistage heating or cooling this timer prevents any higher
stage from coming on until the previous stage has been on for 10
minutes. The timer is extended to 15 minutes for heat pump
auxiliary heat and dual fuel furnace operation.
MINIMUM ON TIME
When a cooling or heating stage is turned on, it will remain on for
at least 3 minutes. These timers are canceled when set points are
changed.
HEAT/COOL SET POINT DIFFERENCE
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A minimum deadband of 2°F is enforced between heating and
cooling set points. This is done by allowing one set point to "push"
the other to maintain this difference.
AUTO CHANGEOVER
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When the auto changeover mode is selected, a change from heat to
cool or cool to heat cannot occur until a demand exists in the new
mode and no demand has appeared in the old mode for 30 minutes
or 10 minutes if option 11 is used. This prevents cycling
continually between heat and cool.
EMERGENCY HEAT MODE
When system is configured for a heat pump and EHEAT mode is
selected, Y outputs are disabled and W outputs only are used for
heat.
POWER-ON CHECK
When power is first applied to the system the large display
indicates the equipment type selected by DIP switches as follows:
1. AC—1-Speed Air Conditioner
2. HP—1-Speed Heat Pump
3. A2—2-Speed Air Conditioner
4. H2—2-Speed Heat Pump
5. AS—1 or 2-Speed Air Conditioner with 3-Stage Auxiliary
Heat
6. HS—1 or 2-Speed Heat Pump with 3-Stage Auxiliary Heat
7. dF—Dual Fuel with 1-Speed Heat Pump
8. d2—Dual Fuel with 2-Speed Heat Pump
OTHER MESSAGES
Small Arrow—A small arrow is located to the left of HEAT and
COOL icons which are located under the two set point displays.
These indicate when cooling or heating equipment is actually
operating. When arrows flash, equipment is waiting to come on but
is being held off by compressor timeguard, cycle timer, or because
LAT or HPT has exceeded its limits and temporarily turned
equipment off.
INITIAL POWER-ON PERFORMANCE
When power is applied to system all dampers are fully opened. As
operation progresses, the system "learns" optimum damper posi-
tions needed to maintain set points in all zones. This learning
process may require up to 2 hours of operation. Allow the system
time to complete its learning.
OVERSHOOT CONTROL
If for any reason a zone is overconditioned by more than 1.5
degrees and the equipment is still operating, that zone's damper
will close until the overconditioning is less than 1.5 degrees.
TEMPERATURE BALANCING
Under heavy load conditions when the HVAC system does not
have sufficient capacity to maintain all set points, the system does
not automatically open all dampers fully. It continues to control
dampers to keep temperature error in each zone the same as all
others.
VENTILATOR MODE
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An automatic ventilation mode is provided by keeping all dampers
at their final position while equipment is off. If the fan is left ON,
more air is supplied to zones which required most conditioning.
Those which required none will have their dampers closed. If 2
hours pass and there is no call for conditioning, all dampers open
fully. In addition, if the mode selection is set to OFF and the fan
selection is set to ON, all dampers will immediately open.
OUTPUTS VS. STAGES
Table 1 lists the active outputs for each stage of each possible
system configuration. G is not shown. It is turned on with any Y.
If installer setup No. 3 is on, G is also turned on with any W.
For 1-stage furnaces and auxiliary heat connect to W1 and leave
W2 open.
For single speed compressors, connect to Y1 and leave Y2 open.
—14—
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