Carrier Gas Furnace 58MXA080


  #1  
Old 11-05-07, 05:56 AM
F
Member
Thread Starter
Join Date: Nov 2007
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Carrier Gas Furnace 58MXA080

my fan ran all the time during summer so I just replaced the tstat a couple of weeks ago.

Now when I turn the heat on ... there is none. Again, fan runs all the time. On the LED it starts off with code 33 and then goes to 13, as advertised.

Kinda lost from here, the reset does not seem to do anything. Should the heat be "running" when I try to do the reset?

Any ideas what the problem could be here?

Thanks
 
  #2  
Old 11-05-07, 06:08 AM
D
Member
Join Date: Aug 2007
Posts: 1,851
Upvotes: 0
Received 0 Upvotes on 0 Posts
Hi fred:

Codes 33 and 13 have to do with an open limit or rollout switch which also explains why the fan is running all the time. Can you read the wiring diagram? Start looking around for a resettable device within the furnace itself.
 
  #3  
Old 11-05-07, 01:22 PM
F
Member
Thread Starter
Join Date: Nov 2007
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Resetting the FRS does nothing.

FWIW, The tstat I used was a Hunter Autosaver 550

I've run the "diagnostics". According to the service manual, I disconnect the R terminal on the control board and then short the Test terminal to the Com. LED is supposed to go out, mine just flashes quickly. When I remove the short it goes back to Code 33.
 
  #4  
Old 11-05-07, 02:40 PM
D
Member
Join Date: Aug 2007
Posts: 1,851
Upvotes: 0
Received 0 Upvotes on 0 Posts
Did the FRS feel like it had tripped? 33 is a open limit or open rollout. Look at the wiring diagram- notice how a red wire leaves #1 on molex plug 1 and goes to the limit, then it goes to the FRS and then returns as a red wire to #7 on the molex plug? Kill the power- check the plug and make sure it's seated tightly on the board. Don't force it or you might push a pin up into the plug. Next, remove the wires from the limit and put them together, often I'll just lay the terminals side by side and use a clothespin to hold them together. Crank the furnace up and see what happens. If that doesn't work, do the same with the FRS. If that doesn't work, take the molex plug off and look inside to see if a pin is out of place or corroded. If that's ok, pull the board off and look on the back. See if maybe some solder has let go or if there's any burn marks. Let us know what you find.
 
  #5  
Old 11-05-07, 03:21 PM
F
Member
Thread Starter
Join Date: Nov 2007
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Originally Posted by daddyjohn
Did the FRS feel like it had tripped?
Hard to say, no real feedback, no positive sensation when pressing the reset. Spongy would be the best description.

Thanks for the other tips. I'll check those out tomorrow. When you say put the wires together, you mean short, right?

What are the odds that the FRS has failed open?

I can get a cheap(ish) control board, maybe I should order that just in case?

Cheers.
 
  #6  
Old 11-06-07, 01:25 PM
F
Member
Thread Starter
Join Date: Nov 2007
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Both limits check out correctly. No voltage across either. Both measure less than 2 ohms. Both show 26v to ground.

Just for fun, I pulled the wires off each and shorted them, started the furnace and got LED codes 33 then 13 just as before. I'm thinking control board.
 
  #7  
Old 11-07-07, 08:57 PM
C
Member
Join Date: Nov 2007
Posts: 16
Upvotes: 0
Received 0 Upvotes on 0 Posts
Only thing that stands out in my mind from what you have said is that since you replaced the tstat you have had an issue. By chance can you pop the tstat off the wall, leaving the subbase still on the wall and take a jumper and jump from R to W (make sure you turn the furnace off at the unit, jump at tstat, then go and turn on the unit and watch what happens). Update afterwards.
 
  #8  
Old 11-07-07, 09:02 PM
C
Member
Join Date: Nov 2007
Posts: 16
Upvotes: 0
Received 0 Upvotes on 0 Posts
Forgot, also check your flue piping, a restriction somewhere?
Sometimes those flash codes will take you only so far, and sometimes down a road away from the problem, have seen that before.
 
 

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