Honeywell 511 Manual

							1 68-0134
C.H.  •  9-93  •  ©Honeywell Inc. 1993  •  Form Number 68-0134
The T8624C,D Chronotherm III Program-
mable Fuel Saver Thermostats provide auto-
matic control of multistage heating/cooling sys-
tems and offer users the highest standard of
comfort and convenience available with energy
savings.

Different schedules may be selected for week-
days, Saturday and Sunday.

Can be programmed in hand (with batteries in-
stalled) or on wall to provide up to four tempera-
ture settings per day.

Large digital clock (liquid crystal display) indi-
cates continuous time, day, current period and
room temperature.

Adaptive Intelligent Recovery™ brings room tem-
perature to programmed temperature at pro-
grammed time, maximizing comfort and energy
savings.

Temperature control program maintains tempera-
ture within 1° F of setpoint.

Temporary program override available by using:
— WARMER and COOLER keys.
— SKIP next period key.
— CHANGE to last period key.

HOLD TEMP key provided for indefinite pro-
gram override (vacation/holiday).

Installer self-test and time delay override save
installation time.

SYSTEM light-emitting diode (LED) indicates
system is energized.
Models available with automatic or manual heat/
cool changeover.

Batteries included provide power to maintain
clock and memory during power failures.

Switching subbase with wiring terminals included.

Powered directly from control transformer, re-
quiring an extra (24V) wire to thermostat.

Fan operation switch to select either independent
or direct thermostat control of fan in heating
included on back of select models.CONTENTS
Specifications ................................................. 2
Ordering Information ..................................... 2
Selection/Application ..................................... 4
Installation ..................................................... 5
Checkout ....................................................... 11
Programming the Thermostat ...................... 14
Operating the Thermostat ............................ 18
Troubleshooting ........................................... 21
Glossary ....................................................... 22
T8624C,D (5-1-1 Day
Programming) Chronotherm
®
III Fuel Saver Thermostats 
						

							2 T8624C,D
SPECIFICATIONS • ORDERING INFORMATION
Ordering Information
When purchasing replacement and modernization products from your TRADELINE® wholesaler or your distributor, refer to the
TRADELINE Catalog or price sheets for complete ordering number, or specify—
1. Model number. 3. System, fan switching desired.
2. Number of heat and cool stages desired. 4. Application.
If you have additional questions, need further information or would like to comment on our products or services, please write or
phone:
1. Your local Honeywell Home and Building Control Sales Office (check white pages of your phone directory).
2. Home and Building Control Customer Satisfaction
Honeywell Inc., 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386 (612) 951-1000
In Canada—Honeywell Limited/Honeywell Limitee, 740 Ellesmere Road, Scarborough, Ontario M1P 2V9. International
Sales and Service offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany,
Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.
Specifications
IMPORTANT: The specifications given in this publi-
cation do not include normal manufacturing toler-
ances. Therefore, this unit may not exactly match
the listed specifications. Also, this product is tested
under closely controlled conditions, and some mi-
nor differences in performance can be expected if
those conditions are changed.
TRADELINE
® MODELS
TRADELINE models (see Table 1) are selected and
packaged to provide ease of stocking and handling
and also maximum replacement value.
LIGHT-EMITTING DIODE (LED): SYSTEM LED
lights during thermostat ON cycle.
VOLTAGE RATING: 15 to 30 Vac.
CURRENT RATING: 1.6A maximum total per stage.
OPERATING HUMIDITY RANGE: 5 to 90 percent
relative humidity, noncondensing.
OPERATING AMBIENT TEMPERATURE RANGE:
40° F to 110° F [4° C to 43° C].
TABLE 1—TRADELINE MODELS.
SETPOINT RANGE: 45° F to 88° F [7° C to 31° C].
CALIBRATION: Self-calibrating thermostat and
thermometer to ±1° F.
SHIPPING TEMPERATURE: -20° F to +120° F [-29° C
to +49° C].
CYCLES PER HOUR ADJUSTMENT:
Heating: First stage of 2-stage heat models—fixed at
3 cph. Second stage of 2-stage heat models or heat
stage of single-stage heat models—factory-set at
6 cph; field-adjustable to 1,3,6 or 9 cph.
Cooling: Factory-set at 3 cph (not field adjustable);
minimum off-time of five minutes.
FINISH: Beige matte with decorative brushed metal
faceplate or Premier White™.
DIMENSIONS: Thermostat (mounted on subbase)—7 in.
[178 mm] long, 5-5/16 in. [135 mm] high, 1-3/4 in.
[44 mm] deep. See Fig. 1 for subbase dimensions.
TYPICAL KEYPAD: See Fig. 2.
ACCESSORIES:
TG586A Locking Cover.
TG512 Versaguard™ Universal Thermostat Guard.
Thermostat
ModelStages Changeover Switching
Number
Heat CoolType
System FanApplication
T8624C 2 1 Auto HEAT-AUTO-COOL-OFF ON-AUTO Multistage
T8624D 2 2 Auto HEAT-AUTO-COOL-OFF ON-AUTO Multistage
T8624D 2 2 Manual HEAT-OFF-COOL ON-AUTO Multistage 
						

							3 68-0134
T8624C,D
SPECIFICATIONS
Fig. 1—T8624 Subbase mounting dimensions in in. [mm].
4    [121]3
4
3     [83]5
16
7 [179]
1     
[46]13
16
5     
[135]5
16
M5181A
43
32
[104]
131
32
[50]
Fig. 2—Typical thermostat keypad.
SYSTEM
RUN
PROGRAM
WAKETIMETEMPERATURE
PRESENT
SETTING
SKIP
NEXT
PERIOD
CHANGE
TO LAST
PERIOD SET
PRESENT
DAY/TIME
HOLD
TEMP
DAY
SET
HEAT/COOLSLEEPLEAVE
AHEADWARMER
BACK COOLER
M2998
WED
LEAVE
AM
HEAT ON
HEAT AUTOCOOLON AUTOFAN
ROOM
RETURN
OFF
PERIOD 
						

							4 T8624C,D
SELECTION/APPLICATION
Selection/Application
The T8624 Thermostat uses the latest microelec-
tronic design and control technology to provide home
and building owners with the highest level of comfort
available and optimal energy savings in a package that is
easy to use and easy to live with.
The following section is a guide to selection and
application of the best thermostat to meet individual
needs.
PROGRAMMING
Does the thermostat selected accommodate the
customer’s daily schedule, lifestyle or work schedule?
Device ProgrammingDaily
Temperature
Selection
T8624C,D 5-1-1 (Mon-Fri,
Sat, Sun)4 heat and
4 cool
T8621A,C,D 7-day (each
day different)4 heat and
4 cool
T8600,01,02,03* 5-1-1 (Mon-Fri,
Sat, Sun)4 heat and
4 cool
The choices are:
* Model not currently available to control multistage
equipment.
IF NEW CONSTRUCTION APPLICATION, CON-
SIDER:
•Equipment type (see manufacturer specifications).
—Staging required.
—System switching required.
—Fan switching required.
•Control wiring—number of conductors required
to operate equipment and thermostat.
IMPORTANT: The T8624 requires an additional con-
ductor to transformer common to provide continu-
ous 24V power for thermostat operation.
IF RETROFIT/REPLACEMENT APPLICATION,
CONSIDER:
•Equipment requirements.
—Staging (heat stages, cool stages).
—System switching (manual: HEAT-OFF-COOL;
automatic: HEAT-AUTO-COOL-OFF). Emer-
gency heat for heat pump application not pro-
vided on T8624.—Fan switching; does fan come on automatically
from thermostat on cooling only (typical gas/
oil heating), or on call for cool and heat (typical
electric heat with single speed fan)?
•Existing wiring
—Are there enough conductors to operate the equip-
ment and the thermostat? Can a new cable be
pulled?
IMPORTANT: The T8624 requires an additional con-
ductor to transformer common to provide continu-
ous 24V power for thermostat operation.
SECURITY
Does the thermostat selected provide access to
AccessTypical
Application Device
Free access to
programming
and adjustment/
override.Home or
owner-occupied
commercial  
building.T8624A,C,D
Restricted
access to
device.Public  
building.T8624 with
TG512 Locking
Guard or
TG586A
Locking Cover.
programmming and the override features that will best
suit the application? The choices are:
SINGLE-STAGE HEAT PUMPS
If home/building owner has a single-stage heat pump,
one option is to use a T8624C or D (see Fig. 8).
The T8624C is a two-stage heating, one-stage cool-
ing programmable thermostat. The T8624D is a two-
stage heating, two-stage cooling programmable thermo-
stat. What both thermostats have in common is separate
W1 and W2 (first and second stage heat) terminals. In
both cases, the W1 can be used for changeover in heat-
ing.
For single-stage compressor applications (both first-
stage heating and first-stage cooling energized through
the Y terminal), simply jumper Y1 and W1.
Note that the recovery algorithm of the T8624 may
cause the compressor to cycle on and off during recov-
ery.
Although the cycle rate for the first stages of heat and
cool are set for hot water systems, the second stage of the
T8624 must be adjusted. Turn the cycle rate adjustment
screws to the hot water setting on both the T8624C and
D to achieve the cycle rate appropriate for heat pumps.
If changeover is utilized in the cooling mode, apply a
normally closed relay.
The above application should be used only on single-
stage heat pumps. 
						

							5 68-0134
Installation
T8624C,D
INSTALLATION
RECYCLING NOTICE
If this control is replacing a control that contains
mercury in a sealed tube, do not place your old control in
the trash. Contact your local waste management author-
ity for instructions regarding recycling and the proper
disposal of your old control.
If you have any questions, call Honeywell Inc. at 1-
800-468-1502.
COMPATIBILITY
The T8624 Thermostats will replace most heating/
cooling system thermostats. As long as ac power is
continuously available to the transformer, the thermostat
will be compatible with any low-volt control system.
IMPORTANT: The T8624 requires an additional con-
ductor to transformer common to provide continu-
ous 24V power for thermostat operation.
WHEN INSTALLING THIS PRODUCT…
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a hazardous
condition.
2. Check the ratings given on the product to make
sure the product is suitable for your application.
3. Installer must be a trained, experienced service
technician.
4. Allow thermostat to warm to room temperature
before operating.
5. After installation is complete, check out product
operation as provided in these instructions.
CAUTION
Disconnect power supply to prevent electricalshock or equipment damage.
LOCATION
Install thermostat and subbase about 5 ft [1.5m] above
the floor in an area with good air circulation at room
temperature.
Do not install thermostat where it may be affected by:
—drafts or dead spots behind doors, in corners or
under cabinets.
—hot or cold air from ducts.
—radiant heat from sun or appliances.
—concealed pipes and chimneys.
—unheated (uncooled) areas such as an outside wall
behind the thermostat.
REPLACING AN EXISTING THERMOSTAT
Turn off thermostat power at furnace or boiler. A two-
transformer system may require turning off two switches
!
or disconnects. Remove any existing wallplate or sub-
base from wall. To avoid miswiring later, label each
wire color with the letter or number on the wiring termi-
nal as the wire is removed.
NEW INSTALLATION
Run cable to a hole at the selected wall location for the
thermostat, and pull about 3 in. [76 mm] of wire through
the opening. Color-coded, 18-gauge thermostat cable with
at least one conductor for each wiring terminal is recom-
mended. Good service practice recommends selecting
cable with one or two more conductors than the immedi-
ate application requires.
MOUNTING SUBBASE
IMPORTANT: Before mounting, set the system switch
to the OFF position.
NOTE: The subbase does not require leveling for proper
operation, but only for appearance.
Fig. 3—Removing thermostat from subbase.
HEAT
AUTO
COOL
OFFO
N
A
U
T
OF
A
N
M 844
Remove thermostat from subbase (Fig. 3).
Mount the subbase directly onto the wall with the
screws and anchors included. If drywall construction,
use plastic anchors. Use the subbase as a template, and
with a pencil, mark the two mounting screw positions
(Fig. 4). Use
3/16 in. bit to drill holes for anchors. Gently tap anchors
into holes until they are flush with the wall surface.
Thread wires through the center opening of the subbase.
Then mount the subbase using the two screws provided.
Gently tighten the screws, level the top surface of the
subbase, and securely tighten the screws. 
						

							6 T8624C,D
INSTALLATION
Fig. 4—Mounting subbase on wall.
WIRES THROUGH
WALL OPENINGWALL 
WALL
ANCHORS
(2)
SUBBASEMOUNTING
HOLES
MOUNTING
SCREWS (2)
M846
Fig. 5—Restrict wiring to recessed area
surrounding terminals.
FOR STRAIGHT
INSERTION –
STRIP 5/16 in. [8 mm]
FOR WRAPAROUND –
STRIP 7/16 in. [11 mm]
RESTRICT
WIRING TO
THIS AREA  
WIRING TO BE BELOW
THIS SURFACETOP SURFACE
OF SUBBASE
FRONT VIEW OF
TERMINAL AREA
CROSS-SECTIONAL VIEW OF
TERMINAL AREA
M 847
WIRING
All wiring must comply with local electrical codes
and ordinances.
Disconnect power before wiring to prevent electrical
shock or equipment damage.
The shape of the terminal barrier permits insertion of
straight or conventional wraparound wiring connections.
Either method is acceptable.
Push excess wire back into the hole, and plug the hole
with nonhardening caulk, putty or insulation to prevent
drafts from affecting thermostat operation.
NOTE: Restrict wiring to the recessed area surrounding
the terminals (Fig. 5) to assure thermostat/subbase
contact.
Refer to Figs. 6-8 for typical hookups of subbase and
thermostat.
ADJUSTING CYCLE RATE
To customize the thermostat cycling performance to
various types of heating equipment, cycle rate adjust-
ment screws are provided on the back of the thermostat
to provide optimum room temperature control.
NOTE: Most applications will not require a change in
cycle rate.
The room air temperature will normally vary slightly
from the comfort temperature setting with the cycling of
the furnace or air conditioner.
The heating cycle rate of this thermostat is factory-set
for gas/oil warm air heating. The cooling cycle rate is
factory-set and cannot be adjusted. The heating cycle
rate can be adjusted by turning one or both cycle rate
adjustment screws located on the back of the thermostat.In multistage heat systems, the cycle rate adjustment
applies to the highest stage of heat only. Screws should
be backed out about one-half to one turn, or be turned in
until tight. See Fig. 9.
TIME/TEMPERATURE CONVERSION
(SOME MODELS)
The display readout may be converted between 12
and 24 hour clock or °C and °F using screws 2A and 2B
as indicated in Fig. 9.
FAN OPERATION OPTION SWITCH
(SELECT MODELS ONLY)
Select models include a fan operation option switch
on the subbase that is visible before the thermostat is
mounted on the subbase. The switch should be in electric
heat position for electric heating systems that do not
have independent fan control.
INSTALLING BATTERIES
Three AAA alkaline batteries are included to provide
backup to prevent program loss in case of power outage.
Install batteries in back of thermostat as shown in Fig.
10.
Without battery backup, the program will remain
about 30 seconds in event of power loss.
IMPORTANT: When batteries are first installed, the
display will flash 1:00 PM and 32
°. The tempera-
ture will stay at 32° F until the thermostat is
powered from the system wiring.
When the batteries are low, the display will flash
REPL BAT. Homeowner will have 20-30 seconds to
install new batteries after removing old batteries from
back of thermostat. After 20-30 seconds, it will be nec-
essary to reprogram. REPL BAT indication will disap- 
						

							7 68-0134T8624C,D
INSTALLATION
Fig. 6—T8624C 2-stage heat/1-stage cool thermostat with HEAT-AUTO-COOL-OFF system and AUTO-ON
fan switching.
NOMINAL 24 Vac POWER MUST BE PRESENT BETWEEN R AND C FOR 
THERMOSTAT OPERATION.
DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION.
M5233
HEATING
TRANSFORMER
R
C
W1
W2
HEAT RELAY 1
HEAT RELAY 2
COOLING
TRANSFORMER
Y1
G
RC
COOLING
CONTACTOR
FAN RELAY
HEAT 1
HIGH
LIMIT
HIGH
LIMIT
L1
(HOT)
L2
HEAT
AUTO
OFF SYSTEM
SWITCH
AUTO
ON FAN
SWITCH
COOL
HEAT 2
2
1
COOL
L1
(HOT)
L2
12
1
23
43
4
SUBBASE 
LOGIC/ 
CONTROL 
CIRCUIT
POWER SUPPLY.  PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
FOR SINGLE TRANSFORMER SYSTEM JUMPER R AND RC.
POWER
SUPPLY
THERMOSTAT 
LOGIC CIRCUIT 
						

							8 T8624C,D
INSTALLATION
DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION.M3765
HEATING
TRANSFORMER R
C
W1
W2HEAT RELAY 1
HEAT RELAY 2
COOLING
TRANSFORMER Y2
Y1
G
RCCOOLING
CONTACTOR 1 COOLING 
CONTACTOR 2
FAN RELAY HIGH
LIMIT
HIGH
LIMIT
HEAT
AUTO
OFFSYSTEM
SWITCH
AUTO
ON FAN
SWITCH
COOLHEAT 2
COOL 2
COOL 1
SUBBASE 
LOGIC/ 
CONTROL 
CIRCUIT
POWER SUPPLY.  PROVIDE DISCONNECT MEANS 
AND OVERLOAD PROTECTION AS REQUIRED.
FOR SINGLE TRANSFORMER SYSTEM, JUMPER R AND RC.
NOMINAL 24 Vac POWER MUST BE PRESENT BETWEEN 
R AND C FOR THERMOSTAT OPERATION.
AVAILABLE ON T8624D MODELS ONLY.POWER
SUPPLY
THERMOSTAT 
LOGIC 
CIRCUIT
1
L1
(HOT)
 L2
2L1
(HOT)
 L2
1
23
4
1
2
3
4HEAT 1
5
5
Fig. 7—T8624D 2-stage heat/2-stage cool thermostat with HEAT-AUTO-COOL-OFF system and AUTO-ON
fan switching. 
						

							9 68-0134T8624C,D
INSTALLATION
Fig. 8—T8624D 2-stage heat/2-stage cool thermostat with HEAT-OFF-COOL system and AUTO-ON fan
switching; auto fan on heat and cool; convertible to auto fan on cool only.
FOR ELECTRIC HEAT APPLICATIONS (AUTO FAN OPERATES WITH W1
AND Y1), USE ONLY ONE TRANSFORMER; JUMPER R AND RC.  SET
 SWITCH TO ELECTRIC POSITION.
  
NOMINAL 24 VAC POWER MUST BE PRESENT BETWEEN R AND C FOR 
THERMOSTAT OPERATION.
DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION.
M1016D
HEATING
TRANSFORMER
R
C
W1
W2
B
STAGE 1
HEAT RELAY
STAGE 2
HEAT RELAY
HEATING DAMPER OR
CHANGEOVER RELAY
COOLING
TRANSFORMER
O
Y2
Y1
G
RC
STAGE 1
COOLING RELAYSTAGE 2
COOLING RELAY COOLING DAMPER OR
CHANGEOVER RELAY
FAN RELAY
HEAT 2HEAT 1
HIGH
LIMIT
HIGH
LIMIT
L1
(HOT)
L2
HEAT
OFF
COOLSYSTEM 
SWITCH
COOL 1
COOL 2
AUTO
ON FAN
SWITCH
L1
(HOT)L2
NON-ELECTRICELECTRIC
FAN 
OPERATION
SWITCH
3
24
1 31
SUBBASE 
LOGIC/ 
CONTROL 
CIRCUIT
5
1
23
4
5 POWER SUPPLY.  PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
FOR GAS OR OIL APPLICATIONS OR ELECTRIC HEAT APPLICATIONS 
WHERE THE FAN OPERATION IS CONTROLLED INDEPENDENTLY OF 
THE THERMOSTAT (AUTO FAN OPERATES WITH Y1 ONLY),  TWO 
TRANSFORMERS  MAY BE USED.  SET SWITCH TO NONELECTRIC 
POSITION.
POWER
SUPPLY
THERMOSTAT 
LOGIC CIRCUIT 
						

							10 T8624C,D
INSTALLATION
Fig. 9—Cycle rate adjustment.
SYSTEM
GRAVITY
AIR/WATER
HOT
WATER
GAS/OIL
WARM AIR
ELECTRIC
WARM AIR1A
OUT 1/2 
TO 1 TURNOUT 1/2 
TO 1 TURN
OUT 1/2 
TO 1 TURN
OUT 1/2 
TO 1 TURN1B
ININ
(FACTORY SETTING)IN INTIME/TEMP
DISPLAY2A2B
24 HRIN
12 HR
o
oC
F
OUT 1/2 
TO 1 TURN
OUT 1/2 
TO 1 TURNIN
M311A1    SCREWS 2A, 2B AVAILABLE ON SOME MODELS ONLY.
1A
2A 2B1B1
CYCLES
PER HOUR
1
3
6
9
pear when thermostat is mounted back on the subbase.
IMPORTANT: For proper thermostat operation, al-
ways replace dead batteries with new alkaline
batteries. We recommend Energizer® batteries.
If batteries are completely dead, the display will go
blank when the thermostat is removed from the subbase.After replacing the batteries, reprogramming will be nec-
essary.
BATTERY PLACEMENT
(NOTE CORRECT PLUS
AND MINUS DIRECTION)M 372A
Fig. 10—Battery placement.
POWER OUTAGES
Backup batteries will hold the programming and keep
the display on during most power outages. Once the
power is restored, the system will resume normal opera-
tion.If the display goes off when power is lost, either the
backup batteries need to be replaced or are not installed.
When power is restored, the display will flash 1:00 PM
as a reminder to reprogram.
MOUNTING THE THERMOSTAT
With system switch set to OFF, hang the thermostat
on the tabs at the top of the subbase (Fig. 11A). Swing
down and press on lower edge until thermostat snaps in
place (Fig. 11B). Open cover and tighten the captive
mounting screws (Fig. 11C).
SETTING DAY AND TIME
Restore 24V power to the thermostat. When power is
applied to the thermostat, the display will read 1:00 PM
and room temperature. It will go off for a few seconds,
then begin to flash on and off. Set present day and time.
Press               .
Press               to set the current day. Each press of
the DAY key advances the display one day.
Press TIME          or              to set the current time.
If the display will not come on:
—Check the mounting of the thermostat to the sub-
base. If loose or misaligned, remove thermostat
and reinstall on the subbase, making sure it is
firmly attached.
—Check to see that heat or cool system power is on.
—Check voltage between R and C; it should be 24 to
30 Vac.SET
PRESENT
DAY/TIME
DAY
AHEADBACK