Carrier furnace quits

Reply

  #1  
Old 12-27-08, 01:06 PM
Member
Thread Starter
Join Date: Dec 2008
Posts: 3
Received 0 Votes on 0 Posts
Carrier furnace quits

My 16 year old Carrier furnace sporatically quits working. This has been going on for 3 years. Worked fine since we bought the house 9 years ago. If I leave the thermostat on "hold temp" it runs fine, and then quits and wont cycle back on. I can get it to go back on by cycling a switch that is held in by front panel cover. Sometimes it works fine and then just quits and then maybe turns back off...or maybe not. Sometimes I can cycle the panel switch and the pilot lites, burners lite, then fan goes on, then the whole thing shuts off after a few minutes....or maybe not. Very frustrating, and any help would be appreciated.
 
Sponsored Links
  #2  
Old 12-28-08, 08:37 AM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
The switch that is held by the cover is just a safety switch. That shouldn't have anything to do with it as long as it stays depressed. Jump the switch and see what happens.
 
  #3  
Old 12-28-08, 12:01 PM
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Received 0 Votes on 0 Posts
I have a feeling you are simply resetting your furnace when you disengage blower door switch, and then rengage it. This in essence is like shutting off your furnace and resetting by turning it back on.

It COULD be that switch, if nothing at all happens with the furnace. But it would seem doubtful that if this was the cause, that the furnace would sometimes work, but then quit.

Please tells us your entire sequence. And then what stays running and what shuts off, when it is not supposed to yet. For example, you said nothing about the inducer even coming on first. Need to know every step.
 
  #4  
Old 12-28-08, 01:06 PM
Member
Thread Starter
Join Date: Dec 2008
Posts: 3
Received 0 Votes on 0 Posts
Thanks for the responses. I'm confident the prob is not the switch. This switch turns off the furnace when you remove the panel, then turns back on when replaced. I simply manually activate the switch and the furnace starts. Sometimes turns on and operates fine, other times it all turns on, then shuts off after 3-5 minutes. I have to wait maybe 5 minutes then manually activate the switch before it comes on again. When I say it comes on, the pilot lites, burners lite and fan starts, in that sequence. Also when I say "turn the switch on", I mean that I prop it in closed position.

The furnace has been working fine since we started using this year for about a month. It just started up again with this intermittant shutting down, on Friday. I'm not up on how it actually works and don't know what an inducer is, but something is telling the burners to shut down, either a heat sensor or another switch or something. Burners & pilot shut down at once and fan about 30 seconds later.

I don't think its the filters (they're fresh) or clogged up fan. The fan works fine while the burners are on. It also works perfectly in the summer when I run the AC. No prob's with the AC, just the furnace.

One more thing, Friday was the 3rd day where I set the thermo to "hold temp". Normally I have it on program (about 1hr in morning then back on for 5 hrs in evening). Recalling past years, problem seemed to be concentrated during "hold temp" setting too.

The worst is, my brother-in-law owns a heating/AC business and I paid his crew to come out and troubleshoot. They could find nothing and tried to sell me a whole new unit.
 
  #5  
Old 12-28-08, 01:19 PM
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Received 0 Votes on 0 Posts
Do you have a test meter for volts-ohms (multi-meter)? Also when the flame shuts off prematurely, does the inducer motor also shut off? That inducer is the motor and fan assembly that sucks exhaust gas out and through the PVC exhaust pipe. It is connected right to that pipe inside the furnace.
 
  #6  
Old 12-28-08, 02:22 PM
Member
Thread Starter
Join Date: Dec 2008
Posts: 3
Received 0 Votes on 0 Posts
yes I do have a multimeter. I just came back from garage. I smacked the thing a few times, blew compressed air everywhere I could and gave it a good vacuming and turned it back on. It ran fine, until....well it didnt shut off. It came up to thermo setting temp and shut off. Now we'll see if it cycles back on when temp drops.

So there is a seperate exhaust fan? I'll check it out and see where and if it goes on. Stay tuned.

BTW the model is 58DRC.
 
  #7  
Old 12-28-08, 05:14 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,503
Received 0 Votes on 0 Posts
From what I can see, your furnace has an intermittent pilot ignition system, which lights the pilot each time the thermostat calls for heat. When the ignition module verifies that the pilot is lit, it turns on the main burner gas.

It may be that the pilot flame detection circuit in the ignition module is defective and not operating reliably to detect the presence of the pilot flame. When that happens, it would shut off the main burner and probably the pilot light as well, and restart the ignition process by lighting the pilot.

This is a problem a competent technician can diagnose if he observes it happening. Unfortunately, you brother in law doesn't appear to have competent repairmen on his service.
 
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: