OPERATIONAL INFORMATION
Five-Minute Compressor Time Guard -- This tim-
er prevents the compressor from starting unless it has been off
for at least 5 minutes. It can be defeated for 1 cycle by simulta-
neously pressing the FAN mode button and the INCREASE
TEMPERATURE button.
Fifteen-Minute Cycle Timer -- This timer prevents
the stall of a heating or cooling cycle until at least 15 minutes
aller the last st;ut of the salne cycle. Its fimction is to assure that
equipment is not cycled more than 4 times per hc This timer is
defeated for 1 cycle when the desired temperatme is manually
changed. It can also be defeated for 1 cycle by simultaneously
pressing the FAN mode button and file INCREASE TEMPER-
ATURE button.
Fifteen-Minute Staging Timer -- In multistage heat-
ing or cooling, this timer prevents any higher stage from
turning on until the preceding stage has been on for 15 minutes.
This timer is defeated if the temperature error is greater than
5° F (usually due to a lmge change in desiled temperature).
Three-Minute Minimum On Time -- In normal op-
eration, when a stage turns on, it will not turn off for a minimum
of 3 minutes.
Heat/Cool Set Points (Desired Tempera-
tures) -- A minimum diffelence of 2° F is required between
heating and cooling set points. This is done by allowing one
setting to "push" the other, to maintain this difference.
Auto Changeover -- When the autochangeover mode is
selected, a change from heat to cool (or vice versa) will not
occur until an opposite mode demand has existed for 20 min-
utes. If the set point is changed, the 20-minute requirement is
deleted. Auto mode may be disabled.
Emergency Heat Mode -- When thermostat is config-
ured as a heat pump and Emergency Heat mode is selected, all
Y signals are locked out and W becomes energized upon a call
for heat.
Heat On and Cool On Icons -- When a heating or
cooling demand exists, the HEAT ON or COOL ON icon will
either remain on or flash. If flashing, the equipment is tempo-
rarily prevented from turning on by one of the timel_ (see
above). While the icon remains on without flashing, the equip-
ment is on.
Power On Check -- When AC power is first applied, all
segments of file display are turned on for a few sec. Following
this, the temperature display indicates the model/configuration
via the following 2-digit code: AC -- 1-speed air conditioneL
HP -- l-speed heat pump, A2 -- 2-speed air conditioner,
H2-- 2-speed heat pump.
Error Codes
-- -- If the thermostat cannot properly read room temperature,
the display will indicate -- (2 dashes) and all outputs (except
the fan if on) will turn off. This is to plevent operation of the
equipment if the thermostat has failed.
E2 -- If the AC line voltage drops below a minimum (brown-
out) level, all outputs are turned off and file display indicates
E2. This condition will remain for 15 sec ;trier proper line volt-
age is restored. If the AC line voltage disappems completely,
the display will immediately go blank.
E3 -- If the thermostat cannot propedy read outdoor tempera-
ture, and it is needed for proper operation (heat pump system
and Option 8 is not set to OF), E3 will flash ;alternately with
room temperature. See Table 3 for error code descriptions.
Table 3 -- Thermostat Troubleshooting
SYMPTOM WHAT TO CHECK
Blank LCD Check for 24 vac between R and C at terminal connections or battery.
Temperature sensor reading out of range. Check sensor for damage. If recycling power
"--" (2 dashes) on temperature display does not clear display, thermostat should be replaced.
"E2" on temperature display Brownout condition or too low of voltage to thermostat. Double check wiring and check for
24 vac between R and C. E2 will clear 15 sec after proper voltage is restored.
"E3" on temperature display The outdoor temperature sensor is open, not connected, or shorted.
After the selected number of hour of blower operation "FILTER" will display on LCD. This
"SERVICE FILTER" on temperature display is to remind the home owner to "check" the filter. Press RESET FILTER button to clear
display and reset timer to 0.
Select COOL mode. Set desired temperature to 10° F below room temperature. Simulta-
neously press FAN and INCREASE TEMPERATURE buttons to defeat timers. Check for
Cooling will not come on COOL ON icon and 24 vac at Y (first-stage) terminal. If present, thermostat is okay and
_roblem is with equipment or wiring. If not present, replace thermostat.
Select HEAT mode. Set desired temperature to 10° F above room temperature. Simultaneously
3tess FAN and INCREASE TEMPERATURE buttons to defeat timers. Check for HEAT ON and
Heating will not come on 24 vac at Y (first-stage) terminal (with heat pump) or W/W1 (with air conditioner) terminal. If
_resent, thermostat is okay and problem is with equipment or wiring. If not present, replace
thermostat.
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