Home » Honeywell » Thermostats » Honeywell RTH6400

Honeywell RTH6400 Support Question

Find answers below for this question about Honeywell RTH6400.
Need a Honeywell RTH6400 manual? We have 1 online manual for this item!

Honeywell Overview Questions Manuals Reviews Videos Research

Question posted by spazzkatz on August 30th, 2020

How To Change To Celsius

how to change my honeywell rth 6400D to celsius?

I Know the Answer!

I have the same question
Request More Information

Current Answers

Answer #1: Posted by i96i on September 2nd, 2020 10:56 AM

This answer was accepted by the poster of the original question.

i96i

Member since:
August 8th, 2020

Points: 8,800

1,100
points

Hello,

https://www.honeywellhome.com/us/en/support/how-do-i-change-from-fahrenheit-to-celsius-or-celsius-to-fahrenheit

I hope it will help you.

Answer #2: Posted by Odin on August 30th, 2020 11:53 AM

Odin

Member since:
April 10th, 2010

Points: 41,236,660

100
points

Honeywell does not document a facility to make that change. If it's possible, you'll have to consult Honeywell. use the contact information at https://www.contacthelp.com/honeywell/customer-service.

Hope this is useful. Please don't forget to click the Accept This Answer button if you do accept it. My aim is to provide reliable helpful answers, not just a lot of them. See https://www.helpowl.com/profile/Odin.

Answer #3: Posted by chocolatesweetboy30 on September 1st, 2020 3:01 AM

chocolatesweetboy30

Member since:
September 1st, 2020

Points: 690

100
points

You can change the temperature display by accessing function 14 in the system settings and switching to 1 or 0

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

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

Owner's Manual - Page 4

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

Owner's Manual - Page 6

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

Owner's Manual - Page 7

M2834 Thermostat M28344 5 69-2210EF-03 5 Insert Quick Reference Card Insert quick reference card into slot in back of thermostat.

Owner's Manual - Page 10

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

Owner's Manual - Page 11

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

Owner's Manual - Page 15

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

Owner's Manual - Page 16

When correct setting is selected, press NEXT to change setting. SETUP Advanced Installation Guide Function 1: System type Press the s or t button to select the type of system you have in your... central air conditioning. (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. M28351 69-2210EF-03 14 TROUBLESHOOTING

Owner's Manual - Page 17

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

Owner's Manual - Page 18

... (system controls fan operation). 1 Electric heat: Use this setting if you have an electric heating system (thermostat controls fan operation). SETUP WIRING Advanced Installation Guide Function 3: Heating fan control Press the s or t button... not appear, please turn to the next page to change setting. When correct setting is selected, press NEXT to display next function. M28351 69-2210EF-03 16

Owner's Manual - Page 19

...% efficiency. 1 Gas/oil steam or gravity system: Use this setting if you have a steam or gravity heat system. M28351 17 69-2210EF-03 TROUBLESHOOTING SETUP RTH6400 Function 5: Heating cycle rate Press the s or t button to select your heating system and optimize its operation: NOTE: If Function 5 does not appear, please turn...

Owner's Manual - Page 20

... display next function. TROUBLESHOOTING Press to option 0 if the outside temperature drops below 50ºF (10ºC). CAUTION: To avoid possible compressor damage, set to change setting. NOTE: System maintains a minimum 3ºF difference between heat and cool settings.

Owner's Manual - Page 21

SETUP WIRING RTH6400 Function 13: Smart Response® Technology Press the s or t button to change setting. M28351 ASSISTANCE TROUBLESHOOTING 19 69-2210EF-03 Press to select Smart Response® Technology: 13 1 Done Next M28356 1 Smart Response® Technology ON 0 Smart ...

Owner's Manual - Page 22

...Advanced Installation Guide AFubnocuttioynou1r4n: eTwemthpermatousrteadt isplay Press the s or t button to select Fahrenheit or Celsius temperature display: 14 0 Done Next 0 Fahrenheit temperature display (°F) 1 Celsius temperature display (°C) M28357 Press to exit and save changes. M28351 ASSISTANCE TROUBLESHOOTING 69-2210EF-03 20 When correct setting is selected, press DONE...

Owner's Manual - Page 23

... page 6). Wrap B wire with electrical tape. 21 69-2210EF-03 Wrap bare end of wire with electrical tape and do not match letters on the thermostat, check the chart below ). Connect O wire to O/B W. Do not use . RTH6400 Wiring If labels do not use C, X or B.

Owner's Manual - Page 24

...set to match your heating equipment (see page 16). Cannot change • Check Function 1: System Type to system setting make sure it is set to acceptable change ranges: • Heat: 40° to 90°F ... Fan Control to make sure it is set to match your thermostat, please try the following suggestions. SETUP WIRING Advanced Installation Guide Troubleshooting If you have difficulty with...

Owner's Manual - Page 25

SETUP WIRING Troubleshooting RTH6400 Heating or • Press SYSTEM button to set system to respond. "Cool On" or "Heat On" is flashing • Compressor protection feature is properly configured ...

Owner's Manual - Page 27

...-1502. Accessories/replacement parts To order, please call Honeywell Customer Care toll-free at 1-800-468-1502. WIRING ASSISTANCE TROUBLESHOOTING 25 69-2210EF-03 Battery holder Part No. 50007072-001 Cover plate assembly Part No. 50002883-001 *Use to cover marks left by old thermostats. To save time, please remove the battery...

Owner's Manual - Page 30

... Printed in a sealed tube. Rev. 08-08 Registered Trademark. D542,677 and other patents pending. © 2008 Honeywell International Inc. 69-2210EF-03 M.S. 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. MERCURY NOTICE: Do not place...