Honeywell Chronotherm III Problem - http://www.hvacmechanic.com/ Forums


Original message

extremer

76.185.175.93

"Honeywell Chronotherm III Problem" , posted Tue 15 Jul 17:50user profileedit/delete messagepost reply


Hey,

My family just recently bought a house that has this thermostat, and we are experiencing some issues with it and I wanted to find out if i could get some help here first before I call someone in, because it seems like a simple issue.

Basically, the thermostat is losing power to the unit around (2:00 thermostat time) and automatically turns the FAN on, which is blazing hot everyday anyway, since I'm in texas. Now the only way to turn this off, is by the switch that controls the things up in my attic is what I found. We have two separate units and they both seem to do this. It will work the next day if I turn it on before 2, and if I turn the AC on before 2'o clock everything will be normal till the next day. I checked the brakers, and didn't seem to find anything of an issue and I really cant figure this one out.

 


Replies:

Houston204



98.196.66.53

"Re(1):Honeywell Chronotherm III Problem" , posted Tue 15 Jul 19:02user profileedit/delete messagepost reply


I would check for loose stat wire connections in the furnace.
Does the attic have any ventilation? Motorized attic ventilation fans can fail causing high attic temperatures. Perhaps you need a new one.

I've seen hot attics start the blower in older furnaces before. When the fan limit hits 150 degrees, it initiates low speed blower operation.

A high limit might do this, though I haven't seen it on a modern furnace.

I have 2 turbine vents, 1 motorized vent, ridge vents and soffet grills, and my attic is still too hot.

"Tip of the Day" Remember to remove power first.

 

 

extremer

76.185.175.93

"Re(2):Honeywell Chronotherm III Problem" , posted Tue 15 Jul 21:02user profileedit/delete messagepost reply


I checked and didn't see anything wrong but I still can't understand why this happens at almost the exact time according to the thermostat each day, once the clock on the thermostat hits 2ish, it turns, even if the real time is like 10AM in the morning.

Now I know what your going to say, check the programming duh! I've checked and the only time that is programmed currently is WAKE( since I can't turn that off )...which is at 6AM t-stat time....

 

 

Houston204



98.196.66.53

"Re(3):Honeywell Chronotherm III Problem" , posted Tue 15 Jul 22:20user profileedit/delete messagepost reply


The Chronotherm 3 is a dinosaur. If the problem occurs by stat time instead of the heat of the day it is a stat issue.

It may be time to update your stat.
The Honeywell RTH7400 is a good replacement.

"Tip of the Day" Remember to remove power first.

 

 

extremer

76.185.175.93

"Re(4):Honeywell Chronotherm III Problem" , posted Tue 15 Jul 23:16:user profileedit/delete messagepost reply


Do you know the appox. cost of replacing these stat's to the ones you suggest, i'm probably going to need two of them. Also would ebay be a good place to get them?

Also would I be able to just use the existing installation on top of this new t-stat? Like the where the t-stat plugs into.

[this message was edited by extremer on Tue 15 Jul 23:22]

 

 

Houston204



98.196.66.53

"Re(5):Honeywell Chronotherm III Problem" , posted Tue 15 Jul 23:33user profileedit/delete messagepost reply


Be sure to remove power to your furnace before replacing your stat to avoid damaging a transformer or fuse.

Write down the existng "terminal = color" combination before removing any wires. If you post this information We can help with the new wiring combination.

Is this a gas furnace? A heatpump? If you do not know post the make and model of your equipment.

I would get them from Home Depot.

"Tip of the Day" Remember to remove power first.

 

 

extremer

76.185.175.93

"Re(6):Honeywell Chronotherm III Problem" , posted Tue 15 Jul 23:50user profileedit/delete messagepost reply


You are the man! I'll see if I can get you those information, because I have no idea which they are =P But thanks alot! You have been a great help and possibly saved me $60 for someone to come out and check this out for me!

 

 

extremer

76.185.175.93

"Re(7):Honeywell Chronotherm III Problem" , posted Wed 16 Jul 16:45user profileedit/delete messagepost reply


Also before I purchase the new t-stats...I want to mention that this is happening for both of the units....could be there something going on with other than the t-stats?

 

 

Houston204



98.196.66.53

"Re(8):Honeywell Chronotherm III Problem" , posted Thu 17 Jul 23:07user profileedit/delete messagepost reply


user error.

"Tip of the Day" Remember to remove power first.

 

 

extremer

76.185.175.93

"Re(9):Honeywell Chronotherm III Problem" , posted Sat 19 Jul 00:06user profileedit/delete messagepost reply


Could be, hm...it most likely seems like to be, because I know that this t-stat unit has to run some of the time right? thats why wake can't be cleared? but I can't figure out why the screen goes blank when this happens...i can't control it!