COMMUNITY FORUM

dlbrad77

10:51AM | 07/27/07
Member Since: 07/26/07
9 lifetime posts
Bvhvac
Hello, I just moved into a house that had to have a thermostat installed. After installation I noticed the AC will not shut off. I have it set in auto, but when I raise the temp on the thermostat it doesnt do anything. The AC will turn off outside, but the fan constantly runs and the blower inside constantly runs. If I switch it off they will both go off. Any Ideas?? It is a ducane system.

dlbrad77

11:21AM | 07/27/07
Member Since: 07/26/07
9 lifetime posts
Now after I took apart the thermostat to look at it, it shuts of when I switch it from auto to on. Hmmmm????

MistressEll

06:55AM | 07/28/07
Member Since: 01/30/05
361 lifetime posts
First if you switch from AUTO to ON and the fan goes OFF sounds like a wiring error.

Second a dual mode thermostat has to be set for HEAT or AC - as a higher set temp would keep the fan running in heat mode (the fan runs until the temp is reached) to get the fan to stop running in a higher set temp - you would have to have the thermostat in AC mode.

As it is presently set up...if you dia the set temp DOWN does the fan stop?

You might also not have the right voltage settings for your fan. Some thermostats are adjustable some are not. You really have to know what voltages are required for your system.

Most common are low voltage but there are also line voltage systems.

dlbrad77

07:20PM | 07/28/07
Member Since: 07/26/07
9 lifetime posts
It does have both AC and Heat on the thermostat. When I switch it to heat it shuts off. When witched to AC, I try to dial up the temp it doesnt shut off. Nothing works when switched to heat. So if I dialed it down nothing happens. It keeps running. All I know about the thermostat is that its a Hunter 40035A-350. Not sure if that helps. It looks cheap to me. Im not sure what the model of the Ducane system is. I will try to find it.

MistressEll

05:32AM | 07/29/07
Member Since: 01/30/05
361 lifetime posts
Obviously you have some issues here, first I suspect wiring errors, assuming you have a correctly compatible thermostat; secondly that there are settings/adjustments that must be made for voltage compatibility, again assuming you've purchased a compatible thermostat.

It sounds as though you haven't consulted the wiring diagram nor the instructions/specifications information packaged with the thermostat to begin with.

It sounds as though you are in totally over your skill-set, since you have been unable to provide even the most basic information to make it possible to BEGIN to suggest a diagnositc path.

Consult a HVAC professional for an in-home visit. Be prepared to be purchasing a new thermostat directly from this individual, as well as his/her time to diagnose the relay, sensor, limit switches, wiring, etc. and install/repair/correct your previous efforts.

Of course there is the obvious, perhaps the set-back temperatures aren't yet being reached with-in the +/- parameters of the thermostat and/or you are making changes expecting instantaneous responses and that's just not how most systems respond.

dlbrad77

08:08PM | 07/29/07
Member Since: 07/26/07
9 lifetime posts
First off I didn't install it so I don't know if it's the right one or not. And sorry for at least trying to fix it myself. I am a 10 year veteran of the Air Force and performed heavy maintenace on fighter aircraft so I tend to try to fix things like this myself. Sorry if thermostats and AC units are not my speciality. I came here for help, not criticism.

dlbrad77

08:12PM | 07/29/07
Member Since: 07/26/07
9 lifetime posts
Thanks Kestenholtz, I will look for that info and see what I come up with. I tried to look at the furnace and could'nt find anything. I can't even get the front panel off. You don't understand the condition of this house I moved into. Haha.

dlbrad77

06:20AM | 07/30/07
Member Since: 07/26/07
9 lifetime posts
I wasn't an electrician on them. I was a crew chief. I didn't mess with any wires my friend. As far as I can see, everything looks wired correctly. I have been doing research all over the web for wiring diagrams and so forth. The door on the front of the system will not come off. I understand that it raises an inch and pulls out, but it won't and being a rental house im not going to trash the panel. Ya know I will just have someone come and look at it. I know the outside unit is an AC10B24. The only thing I did to the wiring is tidy it up at the thermostat. THe guy who put it on left so much wire hanging out so I cleaned them up and put them back in the same position they were in. It was then when I switched from auto to on that it started shutting off. Once again the fans (both outside and inside) will not turn off at all. The AC will, but not the fans. How would you feel if you were asking me how to install landing gear in an aircraft and all I did was criticize you for being out of your league and not knowing what you doing and not having all the facts. Whatever happened to common courtesy and patience? I understand you guys are the experts and im not. I figured my descriptions gave enough info. Sorry. I will go elsewhere. Thanks

Handyman

07:41AM | 07/30/07
Member Since: 11/18/98
187 lifetime posts
First I have to say. These experts are helping you for free. I am in Orlando where it is relatively inexpensive to live and it costs me 80 bucks for an HVAC tech to walk in the door before they do anything.

On my thermostat I have a setting for the fan and the a/c. Both have to be set to auto for them to work in tandem.
Fan can be set to on or auto.

That said in reading most of the back and forth but not all it sounds as if the unit was working prior to you cleaning up the wires on the back of the thermostat and not after.

(Turn off the power)

Then I personally would go back to the thermostat and take it off the wall.

Inspect all the wires and connections maybe a piece of exposed wire is touching another one when it is pushed into the box or maybe it is grounding itself on the box.

A small short can stop the unit.

Also check your breakers. You may hove more than one that could have been tripped.

Good luck on this. And if you do call a pro let us know what they said so the answer will be here for future visitors.

dlbrad77

12:52PM | 07/30/07
Member Since: 07/26/07
9 lifetime posts
First off I didn't come here to argue. I actually hate forums for the sole reason of jerks being on them. I didn't have anything to do with this system. I did not install the thermostat. The only thing I did was clean up the wires and after that the system would shut off when switched to ON. I will see if they are touching or anything to that degree. Thank you, that was good advice. All I wanted was some straight forward simple troubleshooting advice. Im not an electrician so I don't know whether or not if the thermostat is compatible or not. Sorry. After some banging I got the model number of the furnace. Its MPGA075B3A. Im sorry, but when people get on here and start assuming that I installed all of this stuff and that I messed it all up and start saying things like im over my head and start assuming that I know what they are talking about when it comes to electrician lingo, I got upset. I know these guys are free, but they need to understand that we who seek help are not familiar with these sort of things and thus just require some lamen's terms explanation. I mean look at the post by Mistress. Come on! If you still would like to help I would appreciate it. If not I will go elsewhere.
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