The T8624C,D Chronotherm III Programmable Fuel Saver Thermostats provide automatic control of multistage heating/cooling systems and offer users the highest standard of comfort and convenience available with energy savings.
IMPORTANT: The specifications given in this publication do not include normal manufacturing tolerances. Therefore, this unit may not exactly match the listed specifications. Also, this product is tested under closely controlled conditions, and some minor differences in performance can be expected if those conditions are changed.
TRADELINE® MODELS
ACCESSORIES:
TABLE 1—TRADELINE MODELS.
Thermostat Model Number | Stages | Changeover Type | Switching |
Application | ||
Heat | Cool | System | Fan | |||
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 |
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
If you have additional questions, need further information or would like to comment on our products or services, please write or phone:
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.
T8624 Subbase mounting dimensions in in. [mm].
Typical thermostat keypad
The T8624 Thermostat uses the latest microelectronic 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?
IF NEW CONSTRUCTION APPLICATION, CONSIDER:
IF RETROFIT/REPLACEMENT APPLICATION, CONSIDER:
IMPORTANT: The T8624 requires an additional conductor to transformer common to provide continuous 24V power for thermostat operation.
SECURITY
Does the thermostat selected provide access to programmming and the override features that will best suit the application? The choices are
SINGLE-STAGE HEAT PUMPS
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 recommended. Good service practice recommends selecting cable with one or two more conductors than the immediate application requires.
MOUNTING SUBBASE
IMPORTANT: Before mounting, set the system switch to the OFF position.
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 conductor to transformer common to provide continuous 24V power for thermostat operation.
WHEN INSTALLING THIS PRODUCT…
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:
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 subbase from wall. To avoid miswiring later, label each wire color with the letter or number on the wiring terminal as the wire is removed.
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
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
IMPORTANT: When batteries are first installed, the display will flash 1:00 PM and 32°. The temperature 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 necessary to reprogram. REPL BAT indication will disap
T8624C 2-stage heat/1-stage cool thermostat with HEAT-AUTO-COOL-OFF system and AUTO-ON fan switching.
T8624D 2-stage heat/2-stage cool thermostat with HEAT-AUTO-COOL-OFF system and AUTO-ON fan switching.
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.
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.
Cycle rate adjustment.
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 operation. After replacing the batteries, reprogramming will be necessary.
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 Open cover and tighten the captive mounting screws
SETTING DAY AND TIME
HEATING
Move the system switch to HEAT and the fan switch to AUTO. Press WARMER key until the setting is about 10° F [6° C] above room temperature. Heating should start (both stages if multistage), and the fan should run (may be a short delay on forced air systems). Press COOLER key until the setting is about 10° F [6° C] below room temperature. The heating equipment should shut off, followed by the fan.
NOTE: On an AUTO changeover thermostat, the cooling temperature must be set at least 3° F [2° C] above the heating temperature, or display will flash
COOLING
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 (both stages if multistage). Press WARMER key until the setting is about 10° F [6° C] above room temperature. The cooling equipment and fan equipment 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 the switch is in the AUTO position, the fan operates directly with the thermostat call for cooling and also with the
Programming the Thermostat
Comfort temperature
The temperature desired when active and occupying the home.
Energy-saving temperature
The lower (heating) or higher (cooling) temperature that allows savings on heating and cooling costs when asleep or away. Also called the setback (heating) or setup (cooling) temperature
Period | Start Time | Temperature | |
Heating | Cooling | ||
WAKE | 6:00 AM | 70° F | 78° F |
LEAVE | ——— No program ———— | ||
RETURN | ——— No program ———— | ||
SLEEP | 10:00 PM | 60° F | 78° F |
Period key
One of the four keys—WAKE, LEAVE, RETURN or SLEEP—to check or program the start time and temperatue for a time period.
Preprogrammed schedule
This is the schedule programmed into the thermostat at the factory. It sets a night program that provides energy savings when homeowner sets no program, or if personal program is lost for any reason. The program, which is the same for all days of the week, is:
Program
The times and temperatures homeowner sets to define the comfort and energy saving periods for each day schedule.
RETURN—The time period that the house is at a comfortable temperature for family activities in the evening before bedtime.
SLEEP—The time period that the temperature can be set back (winter) or set up (summer) for energy savings because the family is sleeping. It can be set to start at the family’s normal bedtime. Often the SLEEP program is set only for the heating season so family members can sleep cool in the cooling season
Weekday program schedule
The schedule of WAKE, LEAVE, RETURN and SLEEP period start times and temperatures programmed to run
Monday through Friday.
Recovery
The time when the thermostat operates the heating or air conditioning equipment to return the home from the energy saving temperature to the comfort temperature. The thermostat starts the recovery period early so the home will be at the comfort setting by the time the homeowner has chosen.
Saturday program schedule
The schedule of WAKE, LEAVE, RETURN and SLEEP period start times and temperatures programmed to run on Saturdays.
Setback
Reducing the temperature in the home for a set period in heating for energy savings. The lower temperature is the energy saving temperature.
Setup
Raising the temperature in the home for a set period in cooling for energy savings. The higher temperature is the energy saving temperature.
Setpoint
The thermostat temperature setting the homeowner selects. The thermostat turns the heating or cooling equipment on and off to maintain this temperature at the thermostat location until another temperature setting (setpoint) goes into effect.
Sunday program schedule
The schedule of WAKE, LEAVE, RETURN and SLEEP period start times and temperatures programmed to run on Sundays.
SYSTEM light
This light glows whenever the thermostat is calling for heating or air conditioning.
Time period
Honeywell
DOWNLOAD MANUAL
Honeywell T8624C Programming Thermostat User Manual
Johnson Controls T7000e LCD Digital Thermostat Johnson Controls T7000e LCD Digital Thermostat Installation Guide
Honeywell T8635L Microelectronic Communicating Programmable Thermostat Honeywell T8635L Microelectronic Communicating Programmable Thermostat USER’s GUIDE
Hetta HS01RF WIRELESS THERMOSTAT Kit PAIRING INSTRUCTIONS Insert batteries into the Thermostat. Ensure that the…
HEAT-MAT NGT-567-0010 Underfloor Heating Thermostat Menu Introduction The NGT thermostat can switch your underfloor heating…
Honeywell RLV450 PROGRAMMABLE THERMOSTAT READ BEFORE INSTALLING DESCRIPTION * LP appears only for the first…
Honeywell RLV431 Programmable Thermostat Description The RLV431 thermostat can be used to control an electric…