Carrier Access Thermidistat - Manual (Page 11)

Vacation Dehumidification
Normal Dehumidify, Cool to Dehumidify, and Dehumidify OFF,
are all available in vacation mode, and selection of 1 of these can
be different from that of occupied. Vacation dehumidification
selection and set points are remembered the next time vacation is
used.
Cool to dehumidify operates slightly differently, allowing the
home to be cooled to as low as 70°F when trying to achieve
dehumidify set point. The balance between dehumidify and
temperature set point adjustments is 1 percent set point increase
per degree of overcooling for temperatures below 76°F. For
example, at 74°F dehumidify set point is raised 2 percent, and at
72°F dehumidify set point is raised 4 percent. At temperatures
above 76°F, dehumidify set point is not changed.
OPERATIONAL INFORMATION
FIVE-MINUTE COMPRESSOR TIMEGUARD
This timer prevents compressor from starting unless it has been off
for at least 5 minutes. It can be defeated for 1 cycle by
simultaneously pressing FAN button and INCREASE TEMPERA-
TURE button.
FIFTEEN-MINUTE CYCLE TIMER
This timer prevents the start of a heating or cooling cycle until at
least 15 minutes after the last start of the same cycle. Its function
is to assure that equipment is not cycled more than 4 times per hr.
This timer is defeated for 1 cycle when desired temperature is
manually changed. It can also be defeated for 1 cycle by
simultaneously pressing FAN button and INCREASE TEMPERA-
TURE button.
FIFTEEN-MINUTE STAGING TIMER
In multistage heating or cooling, this timer prevents any higher
stage from turning on until preceding stage has been on for 15
minutes. This timer is defeated if temperature error is greater than
5°F (usually due to a large change in desired temperature).
THREE-MINUTE MINIMUM ON TIME
In normal operation, when a stage turns on, it will not turn off for
a minimum of 3 minutes. If the set point is changed, this timer is
automatically canceled, allowing the equipment to turn off imme-
diately when the demand is removed.
HEAT/COOL SET POINTS (DESIRED TEMPERATURE)
A minimum difference of 2° is enforced between heating and
cooling desired temperatures. This is done by allowing 1 setting to
"push" the other, to maintain this difference. This difference is
adjustable via Configuration Option 14.
EQUIPMENT ON INDICATORS
When cooling equipment is on, a COOL icon preceded by a small
triangle is displayed below cool set point. While cooling equip-
ment turn on is delayed by a staging or cycle timer, triangle will
flash. The same is true for HEAT icon and its preceding triangle
located under heat set point. These 2 arrows are also used to
indicate state of humidify and dehumidify outputs. See next
section.
HUMIDIFY AND DEHUMIDIFY INDICATORS
The humidity screen (selected by pressing the HUMIDITY button)
uses the same triangles referenced in the above paragraph to
indicate the state of the HUM and DHUM outputs. When
humidification or dehumidification is active, the triangle under its
set point is turned on.
AUTO CHANGEOVER
When auto changeover mode is selected, a change from heat to
cool (or vice versa) will not occur until an opposite mode demand
has existed for 20 minutes. If set point is changed, 20-minute
requirement is deleted.
EMERGENCY HEAT MODE
When Thermidistat Control is configured as a heat pump and
emergency heat is selected, all Y signals are locked out, and W
becomes energized upon a call for heat.
POWER ON CHECK
When AC power is first applied, all segments of display are turned
on for a few seconds. Following this, temperature display indicates
model/configuration via following 2-digit code:
AC—1-speed air conditioner, HP—1-speed heat pump, A2—2-
speed air conditioner, H2—2-speed heat pump, HS—1-speed heat
pump with 3-stage auxiliary heat, dF—dual fuel, d2—dual fuel
with 2-speed.
ERROR CODES
"--" — If Thermidistat Control cannot properly read room tem-
perature, display will indicate -- and all outputs (except
fan if on) will turn off.
E1, E2 — There is no E1 or E2 error message.
E3 — If Thermidistat Control cannot properly read outdoor
temperature, and it is needed for proper operation, display
will indicate E3.
E4 — If Thermidistat Control’s internal memory fails, E4 will be
displayed. Replace Thermidistat Control.
E5 — If Thermidistat Control cannot properly read humidity, E5
will be displayed. Replace Thermidistat Control.
E6 — If defrost cycle continues for longer than 15 minutes. E6
will be displayed. Check heat pump wiring or for failed
heat pump defrost control.
SMART RECOVERY
With Smart Recovery selected, transition out of setback begins a
fixed time period before selected recovery time and gradually
adjusts room temperature so desired temperature will be achieved
at selected recovery time. The fixed time period is 1.5 hr. It
operates in both heating and cooling. This only applies to
programmable operation.
Thermidistat Control Troubleshooting
SYMPTOM WHAT TO CHECK
No display
Open Thermidistat Control. Check for 24vac between R and C at screw terminals on mounting base. Reassemble, making
sure pins on board engage sockets in mounting base. If display does not appear, replace Thermidistat Control.
"--" in place of room temperature Thermidistat Control cannot properly read room temperature. Replace Thermidistat Control.
"E3" or "--" in place of outdoor temperature Thermidistat Control cannot properly read outdoor temperature. Check outdoor sensor and its wiring.
"E4" or "E5" Internal failure. Replace Thermidistat Control.
"E6" System is stuck in defrost. Check wiring and heat pump defrost control board.
"Clean Filter" icon displayed Filter timer has expired. Clean or replace filter and then press VACATION and HOLD/END buttons together to reset.
Cooling or heating will not come on See Installer Setup to force heating or cooling. Check for 24vac at equipment terminals. If not present, check wiring.
Humidify or dehumidify will not come on See Installer Setup to force HUM or DEHUM. Check for 24vac at equipment terminals. If not present, check wiring.
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