Honeywell T8621A User Manual page 7

COOLING
CAUTION
Do not operate cooling if outdoor temperature is
below 50 F [10 C]. Refer to manufacturer's recom-
mendations.
NOTE: When cooling setting is changed, thermostat will
wait up to 5 minutes before turning on the cooling
equipment. This delay protects the compressor.
Move the system switch to COOL and the fan switch to
AUTO. Press COOLER key until the setting is about 10 F
[6 C] below room temperature. The cooling equipment and
fan should start. Press WARMER key until the setting is
about 10 F [6 C] above room temperature. The cooling
equipment and fan should stop.
NOTE: On an AUTO changeover thermostat, the heating
temperature must be set at least 3 F [2 C] below the
cooling temperature, or display will flash.
FAN
Move the system switch to OFF, and the fan switch to
ON. The fan should run continuously. When the fan switch
is in the AUTO position, fan operates directly with the
cooling system, and also with heating system on some
models.
INSTALLER SELF-TEST (optional)
IMPORTANT
• AC power must be present on thermostat to con-
duct self-test. Relays will not toggle, codes will not
be present and thermostat will not manually exit
self-test without ac power.
• Five-minute time delay on cooling does not func-
tion during self-test.
Perform the following test as a check of all thermostat
functions. If thermostat does not respond as indicated,
thermostat must be replaced.
1. Press AHEAD and BACK keys at the same time.
While holding keys down, all segments of the display should
be on (Fig. 13).
MON
SUN TUE WED THU FRI SAT TEMPORARY
MORNING MIDDAY EVENING NIGHT COOL ON HEAT ON
Fig. 13—All segments on display.
2. Set system switch to OFF. Press AHEAD and BACK
and PRESENT SETTING keys at the same time to enter
self-test.
3. Press each key as listed below, and look for response
listed as key is held down and released.
REPL
AM
PM
BAT
OUTDOOR
SYSTEM
SWITCH
POSITION
OFF
COOL or
AUTO (with
fan in AUTO)
NOTE: If single-stage cooling system, press key twice
instead of 4 times; once to turn cooling, fan and SYS-
TEM LED on, second time to turn off.
OFF
(CHECK
EACH
POSITION)
OFF
HEAT or
AUTO 1
SET
PT
ROOM
M525A
NOTE: If single-stage heating system, press key twice
instead of 4 times; once to turn heating and SYSTEM
LED on, second time to turn off.
OFF
1 For electric heat fan operation—The fan will operate
with the heating system when fan switch is in AUTO.
A HEAT displayed when system switch is in HEAT,
COOL when in COOL, HEAT and COOL when in
AUTO, neither when in OFF. Also, a four-digit code is
displayed, with each digit explained below.
7
PRESS LOOK FOR THIS RESPONSE
THIS KEY KEY
KEY DOWN RELEASED
03 Blank
CHANGE
TO LAST
PERIOD
07 Blank
SKIP
NEXT
PERIOD
15 Blank
PRESENT
SETTING
15 1st stage cooling,
PRESENT
fan and SYSTEM
SETTING
LED on.
15 2nd stage cooling
PRESENT
SETTING
also on.
15 2nd stage cooling off.
PRESENT
SETTING
15 1st stage cooling, fan
PRESENT
SETTING
and SYSTEM LED off.
06 Blank
WARMER
02 Blank
COOLER
05 Blank
AHEAD
04 Blank
BACK
01 Blank
COPY
FROM
00 Blank
COPY
TO
12 See note A
PERIOD
08 Blank
CANCEL
PERIOD
13 Microprocessor mask
no. and revision no.
DAY
09 Blank
SET
HEAT/COOL
14 Blank
SET
PRESENT
DAY/TIME
14 1st stage heating and
SET
PRESENT
SYSTEM LED on.
DAY/TIME
14 2nd stage heating
SET
PRESENT
also on.
DAY/TIME
14 2nd stage heating off.
SET
PRESENT
DAY/TIME
14 1st stage heating and
SET
PRESENT
SYSTEM LED off.
DAY/TIME
10 Blank
HOLD
TEMP
11 Normal operating
RUN
PROGRAM
display.
69-0330—3