Honeywell CT3451 Owner'S Manual Download Page 11

CT3451 PROGRAMMABLE THERMOSTAT

11

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TROUBLESHOOTING

Table 4. Frequently Asked Questions.

If ...

Then ...

Display does not come on.

Make sure the batteries are fresh and installed correctly.

Temperature display does not go lower than 
40°F (4°C) or higher than 99°F (37°C during 
programming.

Your thermostat has reached the temperature limit. Be sure the 
setting range is from 40°F to 99°F (4°C to 37°C).

Display shows flashing or steady “bAtLo.”

The batteries are low; replace them as soon as possible.

Temperature change occurs at the wrong 
time.

Check the program times for the period in question. Be sure that 
AM and PM indications are correct. Make sure the current day and 
time are correct. Reprogram if necessary.

Heating does not come on.

Check that the System switch is set to Heat.

Check the system fuse or circuit breaker and replace or reset, if 
necessary.

Check for correct wiring and good connections.

If display is blank or displays “bAtLo,” install fresh batteries.

Allow time for the furnace to heat up and the fan to come on 
before checking for heat at the register.

If the temperature setting is higher than the current room 
temperature and the flame     is displaying, the thermostat is 
operating correctly. Contact a heating contractor for assistance.

Cooling does not come on.

Check that the System switch is set to Cool.

Check the system fuse or circuit breaker and replace or reset, if 
necessary.

Check for correct wiring and good connections.

If display is blank or says “bAtLo,” install fresh batteries.

The thermostat has a built-in time delay on cooling. Allow five to 
ten minutes after changing the setting before the air conditioner 
starts.

If the temperature setting is lower than the current room 
temperature and the snowflake   is displaying, the thermostat 
is operating correctly. Contact an air conditioning contractor for 
assistance.

The furnace cycles too frequently or the 
system cycle length is too short or too long.

Adjust heat cycle rate in the Customize Your Thermostat section.

The thermostat current setting does not 
match the displayed room temperature to 
within plus or minus 1°.

Plug the wiring hole in the wall behind the mounting plate with 
insulation to prevent drafts that can adversely affect thermostat 
operation.

Be aware that it is normal for the current setting and the 
displayed room temperature to differ occasionally.

During recovery from setback or setup, setting and displayed 
room temperatures can differ for up to 30 minutes after recovery 
period.

System on indicator (   = heat;      = cool) is 
lighted, but no warm or cool air is coming 
from the registers.

Wait five minutes after seeing the flame or snowflake and check 
the registers again. If there is no hot or cool air coming from the 
registers, refer to “Heating does not come on” or “Cooling does not 
come on.”  If everything is checked contact you heating and air 
conditioning contractor.

Thermostat backlight appears dim.

Wait until Replace Battery indicator is illuminated and replace 
batteries.

Replace batteries now.

System on indicator    is flashing.

MInimum off-timer is in effect. Wait five minutes until the 
minimum off-timer is complete.

Summary of Contents for CT3451

Page 1: ...ll com yourhome or call the customer information line at 1 800 468 1502 MERCURY NOTICE If this control is replacing a control that contains mercury in a sealed tube do not place your old control in the trash Dispose of it properly Contact your local waste management authority for instructions regarding recycling and the proper disposal of an old control 1 PREPARE FOR INSTALLATION Check Table 1 to ...

Page 2: ...the C or C1 clock terminals on the Chronotherm Thermostat wiring wallplate Do not allow them to touch or you can damage your transformer Disconnect the wires and wrap them separately using electrical tape do not wrap them together Do not place the wires where they can interfere with the new thermostat operation Record the colors and terminal designation labels of the remaining wires Six or More Th...

Page 3: ...the labels you placed on wires when you removed your old thermostat Match the letter of your old thermostat wire with the terminal of the corresponding letter on your new thermostat Refer to Fig 4 Fig 4 Connecting wiring NOTE To ensure correct mounting of thermostat restrict all wiring to the shaded area in the cen ter of the terminals Loosen the terminal screws and slip each wire beneath its matc...

Page 4: ...2 2 2 1 Y G Rc W 3 R B O HEAT RELAY HEAT DAMPER 3 1 1 HEATING RELAY AND FAN COIL 24V POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED M20536 THERMOSTAT Y G Rc W R B O L1 HOT L2 1 FAN COIL COOLIING CONTRACTOR COIL 24V POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED M20537 THERMOSTAT Y G Rc W R B O 1 Y G Rc W 2 R B O M20511 L1 HOT L2 FAN RELAY HEAT ...

Page 5: ...tteries to operate Remove the battery door located on the right side of the thermostat by pulling outward from the bottom See Fig 13 Insert three AA alkaline batteries as shown in Fig 13 NOTE The thermostat shows a bAtLo message on the digital display to alert the homeowner one to two months before the batteries run out com pletely IMPORTANT Homeowner should replace the batteries once a year to pr...

Page 6: ...keys to display the three digit soft ware revision code Information displayed varies by model Press the key FC factory configuration dis plays A typical example is shown but informa tion displayed varies by model This information is for factory use only Setting C or F Press the key again to display the current setting Press the key to change the C or F indication Setting Heat Cycle Rate see Table ...

Page 7: ...ure while you are sleeping IMPORTANT Always press the keys with your fingertip or sim ilar blunt tool Sharp instruments like pens and pencil points can damage the keyboard Setting Current Time and Day 1 To set current time press Select twice Press or key to set current time NOTE While setting the current time the word SET is displayed 2 To set day of week press Select again Press or key to set cur...

Page 8: ...Sleep temperature Setting Saturday and Sunday Programs To set the Saturday program 1 Wake a Press Select Press or key to set Wake time b Press Select Press or key to set Wake temperature 2 Leave a Press Select Press or key to set Leave time b Press Select Press or key to set Leave temperature 3 Return a Press Select Press or key to set Return time b Press Select Press or key to set Return temperat...

Page 9: ...ou to indefinitely hold a temperature When Hold is active the letters Hld are displayed continuously Hold can be canceled by pressing the Hold key again Press Hold Press or key to set indefinite temperature setting 11 SET FAN AND SYSTEM SWITCHES Manually control Fan and System settings using the switches located at the bottom of the thermostat case See Fig 14 for switch locations Fig 14 Time tempe...

Page 10: ...temperature to start the heating equipment When using the thermostat with the Fuel switch set to the E position for electric heat the fan starts immediately Press the key to lower the temperature setting below the room temperature The heating equipment should shut down Cooling System CAUTION Compressor Damage Hazard Operating at too low of an outdoor temperature can cause compressor damage Do not ...

Page 11: ...s blank or says bAtLo install fresh batteries The thermostat has a built in time delay on cooling Allow five to ten minutes after changing the setting before the air conditioner starts If the temperature setting is lower than the current room temperature and the snowflake is displaying the thermostat is operating correctly Contact an air conditioning contractor for assistance The furnace cycles to...

Page 12: ...ct was in the possession of a consumer Honeywell s sole responsibility shall be to repair or replace the product within the terms stated above HONEYWELL SHALL NOT BE LIABLE FOR ANY LOSS OR DAMAGE OF ANY KIND INCLUDING ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING DIRECTLY OR INDIRECTLY FROM ANY BREACH OF ANY WARRANTY EXPRESS OR IMPLIED OR ANY OTHER FAILURE OF THIS PRODUCT Some states do not al...

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