After relocating T-Stat get no fan, heat, a/c??

Reply

  #1  
Old 10-16-01, 06:57 AM
Visiting Guest
Posts: n/a
I relocated my downstairs T-Stat to a position about 2 feet away. I spliced in the correct size and number of wires (5) and reconnected up in the new position. I then tested by turning on Fan - OK, then I turned on the AC and ran it for about 5 minutes - OK. Then I switched to Heat. Fan kicked on for about 5 seconds then stopped. For the next 20 mintes or so I tried various temp settings etc and switched between Fan and Heat. Fan worked OK, Heat never kicked Fan on. I then went and rechecked my connections. My connections were fine but I could not find 24 volts across any pair of the 5 wires (which I had gotten before). I checked main breakers etc and they were OK. I'm suspecting I did something bad by switching straight from AC to Heat and the transformer has blown a fuse or burnt out. Anyone have any ideas? It's a Carrier gas-fired furnace. If it is the transformer, would that be located on the furnace itself? Is it something I could replace myself?
Thanks to anyone who cares to respond.
TDC
 
Sponsored Links
  #2  
Old 10-16-01, 12:36 PM
hvac4u's Avatar
Member
Join Date: Aug 2001
Location: NW atlanta
Posts: 3,147
Received 0 Votes on 0 Posts
ok, if fan runs when t stat calls for fan on, transformer and fuse are good. when you say fan will not kick on in heat, what is happening? fan (blower) should not come on until bonnet temp setting is reached, or by time if you have a circuit board. you may have an inducer draft blower that kicks on when call for heat (jump W and R at t stat) let us know if you have a standing pilot,circuit board, age, etc. are burners coming on?
 
  #3  
Old 10-16-01, 01:09 PM
Visiting Guest
Posts: n/a
I guess I need to be a bit clearer - There are 2 switches on the T-stat. One says Fan ON/AUTO, the other is HEAT/OFF/COOL. After I relocated the T-stat, I switched Fan to ON and the HEAT/OFF/COOL to OFF. The fan came on fine. I then switched the Fan to Auto and the HEAT/OFF/COOL to COOL. The Fan came on and cold air started blowing after about 3 minutes. So this looked OK too. I then immediately switched the HEAT/OFF/COOL switch to HEAT, the fan came on for about 5 seconds then stopped. From that point on I couldn't get the Fan to come on (in Auto position) when the other switch was on HEAT no matter what the temp setting or how long I waited (up to, say, 5 mins). I then checked the wires and discovered no voltage anywhere! So, right now, absolutely nothing will work. What's going on???
 
  #4  
Old 10-16-01, 01:29 PM
hvac4u's Avatar
Member
Join Date: Aug 2001
Location: NW atlanta
Posts: 3,147
Received 0 Votes on 0 Posts
is fan on switch working at this point? do you have a pilot light? what kind of ignition?
 
  #5  
Old 10-16-01, 01:46 PM
Visiting Guest
Posts: n/a
There is no voltage at T-Stat right now so nothing will work. That is why I suspect the transformer is blown or something. I haven't looked in the furnace so I don't know about pilot lights or anything.
 
  #6  
Old 10-17-01, 06:01 AM
Visiting Guest
Posts: n/a
hvac4u,
Thanks for the responses but I found and fixed the problem. As I suspected, there was a blown fuse on the circuit board behind the furnace outside panel. It is a 3 amp car-type fuse and, actually, there is a notice posted on the panel about the fuse location etc. In case anyone else attempts the same fuse replacement, watch out for a switch on the outside case of the furnace that will allow the unit to work only when the panel is in place! I had replaced the fuse and still got no voltage on the wires when I put a meter on them. Then I noticed a switch on the body of the furnace with 2 wires to it. This switch is closed when the panel is replaced. I guess it's a safety feature.

TDC
 
  #7  
Old 10-17-01, 06:26 PM
Visiting Guest
Posts: n/a
Wink

Ahhhhh the PURPLE FUSE...
Always turn the power foo before working, YES even with 24V!
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: