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Question posted by sready6 on August 12th, 2013

Honeywell Rth6400 Series

I have mine set 4 ways througout the day. 78 for day and at 4:00 pm to change to 75 and 10:00 at night to change to 70, for some reason around 7:00 it changes to 70 degress when it's not suppse to change to 70's till 10 pm. It does this sometimes during the day settings too, changes to another degree when it shouldn't. Can you help. What I need to do.

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Related Honeywell RTH6400 Manual Pages

Owner's Manual - Page 1

Quick Installation Guide RTH6400 Series Programmable Thermostat 69-2210EF-03

Owner's Manual - Page 2

Installation is preset for wiring assistance before returning the thermostat to match your new thermostat to the store. 69-2210EF-03 ii Call 1-800-468-1502 for the most common system We are here to help. It is Easy Label wires and remove your old thermostat Install and wire your new thermostat Set your heating/cooling system -

Owner's Manual - Page 4

2 Remove Old Thermostat Remove old thermostat but leave wallplate with wires attached. Old thermostat Cover 69-2210EF-03 2 M28099 Leave wallplate in place Is there a sealed tube containing mercury? If so, see back cover for proper disposal instructions.

Owner's Manual - Page 6

Pull here to remove wallplate from New Thermostat Remove battery holder. Wallplate M28343 69-2210EF-03 4 4 Separate Wallplate from new thermostat.

Owner's Manual - Page 10

Back of thermostat M28346 69-2210EF-03 8 8 Install Batteries Install two AA alkaline batteries.

Owner's Manual - Page 11

M28347 9 69-2210EF-03 9 Install Thermostat onto Wallplate Install thermostat onto the wallplate on the wall.

Owner's Manual - Page 15

Function 1 Setting 0 Done Next Press DONE to next function. 13 69-2210EF-03 TROUBLESHOOTING M28349 Press NEXT to advance to exit and save settings. SETUP WIRING ASSISTANCE M28348 Press s or t to change settings. RTH6400 ASybsotuetmyosuertunpew thermostat Press and hold the s and FAN buttons until the screen changes (approximately 5 seconds).

Owner's Manual - Page 16

...Press the s or t button to select the type of system you have in your home: 10 WIRING ASSISTANCE Done Next M28350 0 Heating & cooling: Gas, oil or electric heating with central air... (Use this setting if you could turn the fan on and off with a fan switch on your old thermostat.) Press to display next function. When correct setting is selected, press NEXT to change setting. M28351 69-...

Owner's Manual - Page 17

...RTH6400 Function 2: Heat pump changeover valve Press the s or t button to select whether your changeover valve is selected, press NEXT to the O/B W wire terminal (see page 21). When correct setting... 0 Cooling changeover valve: Use this setting if you connected a wire labeled "O" to the O/B W wire terminal (see page 21). 1 Heating changeover valve: Use this setting if you connected a wire labeled ...

Owner's Manual - Page 18

...display next function. M28351 69-2210EF-03 16 When correct setting is selected, press NEXT to change setting. SETUP WIRING Advanced Installation Guide Function 3: Heating fan control ...oil heat: Use this setting if you have a gas or oil heating system (system controls fan operation). 1 Electric heat: Use this setting if you have an electric heating system (thermostat controls fan operation).

Owner's Manual - Page 19

...change setting. When correct setting is less than 90% efficient. 9 Electric furnace: Use this setting if you have any type of electric heating system. 3 Hot water or high-efficiency furnace: Use this setting... or gravity system: Use this setting if you have a standard gas or oil furnace that is selected, press NEXT to display next function. SETUP RTH6400 Function 5: Heating cycle rate Press...

Owner's Manual - Page 20

... TROUBLESHOOTING Press to display next function. When correct setting is selected, press NEXT to change setting. NOTE: System maintains a minimum 3ºF difference between heat and cool settings. CAUTION: To avoid possible compressor damage, set to select Manual or Auto Changeover: 12 0 WIRING...or t button to option 0 if the outside temperature drops below 50ºF (10ºC).

Owner's Manual - Page 21

... Next M28356 1 Smart Response® Technology ON 0 Smart Response® Technology OFF NOTE: See Operating Manual for information on Smart Response® Technology. SETUP WIRING RTH6400 Function 13: Smart Response® Technology Press the s or t button to display next function. Press to change setting.

Owner's Manual - Page 23

... will be connected to terminal as shown here (see page 6). Wrap bare end of wire with electrical tape and do not match letters on the thermostat, check the chart below and connect to both O and B if you have a heat pump. Wrap B wire with electrical tape. 21 69-2210EF-03...

Owner's Manual - Page 24

...change • Check Function 1: System Type to system setting make sure it is set to acceptable change ranges: • Heat: 40° to 90°F (4.5° to 32°C). • Cool: 50° to 99°F (10... • Make sure fresh AA alkaline batteries are set to match your to match your thermostat, please try the following suggestions. Most problems can be corrected quickly and easily...

Owner's Manual - Page 25

... safely, without damage to make sure in system (see page 15). cool mode ASSISTANCE TROUBLESHOOTING 23 69-2210EF-03 SETUP WIRING Troubleshooting RTH6400 Heating or • Press SYSTEM button to set system to Cool. Heat pump • Check Function 2: Heat Pump issues cool air Changeover Valve to the compressor. Wait 5 minutes for...

Owner's Manual - Page 26

... Heating system• Check Function 1: System Type to is running at the make sure it is set to match your heating and cooling equipment (see page 14). same time (or • Grasp and pull thermostat away heat does not from wallplate. Check to make sure turn off) bare wires are not touching...

Owner's Manual - Page 27

... cover marks left by old thermostats. Accessories/replacement parts To order, please call Honeywell Customer Care toll-free at 1-800-468-1502. WIRING ASSISTANCE TROUBLESHOOTING 25 69-2210EF-03 SETUP ACbuosutotmyoeur ransseiwsttahnecremostat RTH6400 For assistance with this product, please visit http://DIYthermostats.honeywell.com or call Honeywell Customer Care toll-free at 1-800...

Owner's Manual - Page 28

... OR ANY OTHER FAILURE OF THIS PRODUCT. In Canada, write Retail Products ON15-02H, Honeywell Limited/ Honeywell Limitée, 35 Dynamic Drive, Toronto, Ontario M1V4Z9. 69-2210EF-03 26 This warranty... which occurred while the product was caused by the consumer. 1-year limited warranty Honeywell warrants this product, excluding battery, to repair or replace the product within the terms...

Owner's Manual - Page 30

... Douglas Drive North Golden Valley, MN 55422 Honeywell Limited-Honeywell Limitée 35 Dynamic Drive Toronto, Ontario M1V 4Z9 http://DIYthermostats.honeywell.com Printed in a sealed tube. US Patent No. Contact your old thermostat in the trash if it contains mercury in U.S.A. on recycled paper containing at least 10% post-consumer paper fibers. ® U.S. D542...