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ckcrew 12-06-2006 08:06 AM

replaced t-stat and now my ac unit does not work
ive bought a home recently. i decided to replace the old t-stat with a programmable honeywell RTH230B. the house has a electric ac/heater unit that worked fine before i replaced the t-stat. i think ive connected the wires correctly. white wire to W. yellow wire to Y. green wire to G. red wire to Rh with a jumper connecting Rh and Rc. ive put batteries in the t-stat and turned the power back on for the ac unit at the breaker box. and still nothing. no ac, no heating, no fan. since im new to this stuff, i just feel like there is something very simple im overlooking. i would appreciate any suggestions. thanks

#CARRIERMAN 12-06-2006 11:26 AM

Hi ckcrew

Were there any wires you did not hook up?. And did you set thermostat up for the system you have?. If you will answer these for me, we will get you going.


ckcrew 12-06-2006 11:44 AM

hi carrierman,

from the wall there are 4 wires. red, white, yellow, and green. so no, there arent any wires that have not been connected.

and im not exactly sure how i would set up the t-stat for the system i have. i have programmed the t-stat for correct temperature and configured all the different settings. i have gone through the entire manual severval times and i did not see a "set up" for the system i have. i can try tweaking something if there is sign of life. but there's no heat, cool, or fan. haha, im freezing my butt off at night.

ckcrew 12-07-2006 10:02 AM

i went home yesterday and realized i actually have a gas furnace. gas furnace and electric ac

mdshunk 12-07-2006 07:12 PM

Jeeze, it sure does sound like you hooked it up right. Assuming you followed the manual to the stat with regard to setting the temperature and setting it to heating, it should work. My best guess at this point would be that perhaps the R conductor got against something and blew the fuse on the board in the furnace. The other option is that maybe one of the conductors broke off at the stat connection, and it only looks connected. Is the display lit up on the thermostat? or is it completely blank?

One thing you could do would be to manually tough R and G and see if your furnace fan comes on. That would sorta narrow it down between a stat issue or a possible furnace (blown fuse) issue.

ckcrew 12-07-2006 10:50 PM

i fixed the problem. and it took about two seconds to fix. fearing that i had shorted something, i went back into the attic to investigate. and i noticed a switch that i had previously turned off the very first time i went into the attic. then i felt like a real dummy. i turned the switch on and went back to the thermostat. switched fan on and bingo the fan came on. i turned the air on too and it works fine. gas guy is coming tomorrow to turn the gas on and i will have heat. thank you for your suggestions. i was hoping for a simple solution but i didnt know it was gonna be THAT easy!

This is my first home so im sure im going to have all kind of questions about home improvement. this site is going to be invaluable. thanks

mdshunk 12-08-2006 05:04 PM

Glad everything worked out for you.

Yeah, every piece of HVAC equipment needs to have a disconnect within sight of the equipment. For low current stuff, like your gas furnace, it might be an ordinary "light switch". That's fooled more than one person, especially if the switch is mounted some other place than right on the equipment. I like to print out a label with my label machine and label the switch plate so there's no confusion. Some jurisdictions require bright red plates that are clearly labeled "furnace emergency switch" or similar.

ckcrew 12-08-2006 11:12 PM

yeah, it was a simple light switch for me too. i'm going to label it tomorrow. that's great advice.

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