Two-Stage Operation; Clock Backup; Fan Operation; Emergency Heat - Carrier Aquazone 50QE900 Installation And Operating Instructions Manual

Two-Stage Operation —
cool is turned on when the first stage has been on for a mini-
mum of 2 minutes and the temperature differential from the set
point is equal to or greater than the set point plus the deadband
plus 2 degrees.
Clock Backup —
In the event of a power loss, the ther-
mostat will keep time for a minimum of 48 hours without
external power or batteries.
Fan Operation —
If Fan On is selected, the fan will run
continuously during occupied schedule (except when Mode is
switched to OFF). The fan will be off during unoccupied
schedule except during heating or cooling operation.
If Fan On is not selected, the fan will only operate during
heating or cooling operation.
Emergency Heat —
Emergency heat is available for
heat pump applications. To turn on emergency heat, press and
hold the Fan button. While holding the Fan button, press the
UP button for 2 seconds. An ''EH'' will be displayed. During
emergency heat, the fan will operate and the second stage of
heat will be energized (locking out the first stage compressor).
To exit emergency heat, press and hold the Fan button. While
holding the Fan button, press the UP button for 2 seconds. Dur-
ing emergency heat, only OFF and HEAT modes are available.
Holiday Mode —
When the thermostat is in Holiday
mode, the thermostat will operate under Unoccupied set points.
To configure and activate the Holiday mode, press the Holiday
button. The ''HOL'' icon will be displayed along with the re-
maining days of Holiday mode operation. Press the UP or
PROBLEM
Display on thermostat not illuminated.
''Service Filter'' is displayed on thermostat.
Cooling will not energize.
Heating will not energize.
When controlling a heat pump, heat comes on
during cooling cycle.
The second stage of heat or

TROUBLESHOOTING

Table 4 — Thermostat Troubleshooting
Check for 24 vac at the R terminal connection. Terminal R must be connected
for proper thermostat operation.
After the configured number of blower operating hours, the Service Filter mes-
sage will be displayed. This reminds the owner to replace the filter. Reset the
Service Filter feature to reset the blower operation timer to 0 hours.
Select COOL mode. Decrease cooling set point to 10 degrees below room tem-
perature. Check for 24 vac at Y1 terminal. If present, thermostat is operating
correctly and problem is with wiring or equipment. If 24 vac is not present,
replace the thermostat. Check for Compressor Cycle per Hour Limit. Cooling
may be locked out.
Select HEAT mode. Increase heating set point to 10 degrees above room tem-
perature. Check for 24 vac at W1/O/B terminal. If present, thermostat is operat-
ing correctly and problem is with wiring or equipment. If 24 vac is not present,
replace the thermostat.
Configure thermostat for heat pump operation (Table 2, Step 3).
DOWN ARROWS to select the number of days that the holi-
day schedule will be in effect. A value of 0 disables Holiday
mode. The duration can be set from 1 to 99 days. The thermo-
stat will enter Holiday mode on midnight of the next day after
the mode has been activated. Holiday mode will remain in
effect until midnight of the last configured day.
If the Holiday mode is in effect, the number of days remain-
ing will blink on and off and the ''Unoccupied'' icon will be
displayed. The Override button will be active during Holiday
mode.
To turn off the Holiday mode before the remaining config-
ured days have passed, press the Holiday button to enter into
the configuration mode. Press the DOWN ARROW to set the
number of days to zero. Holiday mode will be disabled.
Keypad Lock —
To prevent unauthorized use of the ther-
mostat, the front panel buttons can be disabled. To disable or
lock the keypad, press and hold the Mode button. While hold-
ing down the Mode button, press the UP and DOWN ARROW
buttons simultaneously. The ''Locked'' icon will appear on the
display.
The thermostat is unlocked by performing the same proce-
dure. Press and hold the Mode button. While holding down the
Mode button, press the UP and DOWN ARROW buttons
simultaneously. The ''Locked'' icon will be removed from the
display.
SOLUTION
7