Question about Honeywell Air Conditioners

1 Answer

Digital thermostat not working

We have a Honeywell digital thermostat (# on tag on back of the unit are...
T8400C 1024). I noticed today that our fan wasn't running for awhile when I went to check the thermo. to see if it was on auto or on, the screen was blank. I tried to turn on the furnace and ac but nothing is working.

Posted by on

  • boberding Sep 15, 2008

    I just figured that was obvious... the unit doesn't have batteries. As it turns out it was a problem with the circuit board but thanks for the insightful comment.

×

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Prodigy:

    An expert who has answered 500 questions.

  • Expert
  • 540 Answers

Can you saY, Batteries!

Posted on Sep 15, 2008

  • Anonymous Apr 26, 2016

    No, but I can say you're a dumbazz because this doesn't use batteries!

×

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

The display on my thermostat T8400C 1024 isn't working. Everything else works but the heat and the flame is not igniting either. Please help.


Sounds like a manual limit needs to be reset (thermal disc). Generally the manual limits are around the exhaust - backdraft, or burner assembly - flame rollout.

Feb 15, 2014 | Honeywell Air Conditioners

1 Answer

Honeywell thermostat t8400c


Probably no power (24 volt) to the unit. Check 3amp fuse in the air handler. Also check that it's wired properly.

Sep 19, 2013 | Air Conditioners

1 Answer

I HAVE A HONEYWELL MANUAL THERMOSTAT NO BATTERIES ALL IT HAS ON THE BACK IS T8400C 1099 (2) 0710 1B HELP, IT DOES NOT SHOW ANY THING THE SCREEN IS BLANK


This model of Honeywell thermostat uses the 24v from the unit to power it. One of three things must have happened.

1. You have lost power to the furnace, therefore no power to thermostat.
2. You only have 4 wires hooked up on the thermostat and not 5. A lot of older homes had just 4 wire running to the thermostat, which will not work for this thermostat. You should have a wire connected to the (C) or (B) terminal on the thermostat, which ever one they have, I can't remember off hand. These are the Common terminals. They have to have the common from the furnace 24v power to operate.
3. Faulty thermostat, which will obviously have to be replaced.

Hope this helps and gets you to cooler days!

Jun 28, 2012 | Honeywell Air Conditioners

1 Answer

Changed honeywell T8400C 1024 to Hunter 44760, I have five wires white, red, yelliow, green, blue. Hunter Thermostat reads "NO A/C Power.


Hi,
On the t-stat and the furnace make sure the wires are hooked like this...

Red to R
White to W
Green to G
Yellow to Y
Blue to C

then it should work..

Thermostat Wiring and Terminal Designations

heatman101

Jun 12, 2011 | Air Conditioners

1 Answer

I have a Honeywell T8400C 1024 thermostat. the last two nights, our heat continues to run without shutting off at the pre-set temperature. We have woken up to 81 degrees in our house. What is the...


Hello
Try taking the batteries out for 5 min,or disconnect power for 5min.
To clear it out.
Then re input all your times days and temps,

Is t stat in a cold location near a door or window?this could also override your settings,most progrmamble stats will go into override at 58.f im guessing this is not your problem.

If it continues after you reset,i would consider a new thermostat.

Hope this helps.

Jan 28, 2010 | Air Conditioners

1 Answer

Honeywell thermostat T8400c started flashing, heat/cool was off. Display flashes all icons (heat and cooling icons, temperatures, everything) and on the oppposite flash, the setpoint is displayed. The fan...


Based on the simplicity of this particular t-stat, I really think that it is bad and needs to be replaced. They do not make this particular model anymore. I have included a link to the operators manual for the stat. Good luck!

http://customer.honeywell.com/techlit/pdf/PackedLit/69-1491.pdf

Apr 05, 2009 | Air Conditioners

1 Answer

I have just purchased a honeywell ct87n, could you please provide a schematic in order to connect it properly. I had someone install a honeywell digital thermostat several months ago, he did not tag the...


G to the manufactures webpage and type in model # and look upspecs . r- red y-cool w-white g-fan .. The red should be connected to rh--rc already by a jumper wire.

Sep 03, 2008 | Honeywell Air Conditioners

Not finding what you are looking for?
Air Conditioners Logo

Related Topics:

987 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honeywell Air Conditioners Experts

MightyMikeJr

Level 3 Expert

347 Answers

cheapdiesel

Level 1 Expert

5 Answers

Steve Kjr

Level 1 Expert

41 Answers

Are you a Honeywell Air Conditioner Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...