18
System
Press
Look For This Response
Switch
This
Key
Position
Key
Down
Key Released
OFF
06
Blank
02
Blank
05
Blank
04
Blank
01
Blank
00
Blank
(CHECK
12
See note A .
EACH
POSITION)
OFF
08
Blank
13
Microprocessor mask
no. and revision no.
09
Blank
14
Blank
HEAT or
14
1st stage heating and
AUTO
SYSTEM LED on.
14
2nd stage heating
also on.
14
2nd stage heating off.
14
1st stage heating and
SYSTEM LED off.
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
10
Blank
11
Normal operating
display.
END SELF-TEST
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.
T8621A,C,D
CHECKOUT
INSTALLER SELF-TEST (OPTIONAL)
IMPORTANT:
1. Thermostat must have ac power to perform self-
test. Relays will not toggle, codes will not be
present and thermostat will not manually exit
self-test without ac power.
2. Five-minute time delay on cooling does not function
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 (see Fig. 18).
Fig. 18—All segments on display.
WARMER
2. Set the system switch to OFF. Press and release
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 re-
sponses listed as key is held down and released.
System
Press
Look For This Response
Switch
This
Key
Position
Key
Down
Key Released
OFF
03
Blank
07
Blank
15
Blank
COOL or
15
1st stage cooling,
AUTO
fan and SYSTEM
LED on.
15
2nd stage cooling
also on.
15
2nd stage cooling
off.
15
1st stage cooling,
fan and SYSTEM
LED off.
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.
(with fan
in AUTO)
M 525A
AM
SUN
MORNING
REPL
BAT
SET
PT
ROOM
PM
OUTDOOR
TUE WED THU FRI SAT TEMPORARY
MON
MIDDAY EVENING NIGHT
COOL ON HEAT ON
1
RUN
PROGRAM
CHANGE
TO LAST
PERIOD
PRESENT
SETTING
PRESENT
SETTING
AHEAD
COOLER
BACK
COPY
FROM
COPY
TO
PERIOD
CANCEL
PERIOD
DAY
SET
HEAT/COOL
SET
PRESENT
DAY/TIME
SET
PRESENT
DAY/TIME
SET
PRESENT
DAY/TIME
HOLD
TEMP
SET
PRESENT
DAY/TIME
SET
PRESENT
DAY/TIME
SKIP
NEXT
PERIOD
PRESENT
SETTING
PRESENT
SETTING
PRESENT
SETTING
