Trane TUX100C948D2 Problem

Reply

  #1  
Old 10-19-12, 09:02 AM
Member
Thread Starter
Join Date: Oct 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Trane TUX100C948D2 Problem

History - Furnace installed end of 2003 by Air Tech. Air Tech called to fix cycling on and off in 11/14/2006. They said drain hose was block by a small piece of cardboard paper.

Diagnosis:
  • 3 led lights blinking indicating pressure switch error.
  • Checked and verified cleared Intake and exhaust vents to outside by blowing out with shopvac.
  • Removed and cleaned the black hose entering the pressure switch and the clear hose at the back.
  • Checked all the clear drain hoses in the furnace to make sure they are attached and cleared.
  • New Filter
  • Removed and cleaned Flame sensor
  • Right now the furnace works with the black hose that runs from the pressure switch to the burner box is unplugged. But soon as I plug it in it shuts down and blink 3 times.
  • The main blower is squeaking when it runs.
  • It runs for 5 minutes and shuts down.
  • It starts again immediately and shuts down after 5 minutes. The cycle repeats…….


Any input will be appreciated.

PP
 
Sponsored Links
  #2  
Old 10-19-12, 10:43 AM
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
What do you mean when you say it runs for five minutes? The burners stay lit for that time and then shut off? Does it run for that time when the hose is properly connected?
 
  #3  
Old 10-19-12, 11:20 AM
Member
Thread Starter
Join Date: Oct 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
With black hose disconnected from the pressure switch at the pressure switch, It runs for 5 minutes and shuts down.

It starts again immediately and shuts down after 5 minutes. The cycle repeats…….



With the black hose connected at the pressure switch, furnace shuts off. Exhaust blower tried and tried but igniter won't glow to allow the gas valve to open....
 
  #4  
Old 10-19-12, 04:58 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
Take the cover off the burner compartment of the furnace.

Observe the sequence of events that occurs at the furnace when you turn up the thermostat and post that sequence of events in order and in detail.

Unfortunately, your comments so far are vague and not of much help.
 
  #5  
Old 10-20-12, 06:57 AM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,245
Received 0 Votes on 0 Posts
How did you blow out the intake/exhaust exactly. If you remove the cover off the burner box. Using a flashlight, look up into the intake pipe from inside the burner box. Is there ANY blockage? Also, please do as Seattlepioneer requested...
 
  #6  
Old 10-22-12, 07:33 AM
Member
Thread Starter
Join Date: Oct 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Let see if I can make it more detail.

1. Set thermostate to heat
2. Set temperature 6 degrees above room temperature. Room temperature is 64 degree. Set thermostate temperature to 70 degree.
3. At the furnace (Tux100C948), exhaust fan (Inducer) comes on.
4. Some time later (I didn't time it), exhaust fan shut down. Red led lights blinking 3 times with a slight pause in between.
6. About 10 seconds later, exhaust fan comes one again. It shut down. It repeated off and on...................It doesn't work so I proceed with the following:
  • Turned the breaker off. Builder's electrician never put a switch to the furnace.
  • Checked and verified cleared Intake and exhaust vents to outside by blowing out with shopvac. I lifted the intake pipe (fresh air intake pipe on the left of the furnace). Inserted the shop vac exhaust part of the vacuum and blew it out. I ran out side of the house and felt the amount of air blowing out of the pipe. I didn't have any way of measuring the air flow coming out but I felt with my hand that the air flow was about the same as the vacuum. The same process was done for the exhaust pipe.
  • Removed and cleaned the black hose entering the pressure switch and the clear hose at the back.
  • Checked all the clear drain hoses in the furnace to make sure they are attached and cleared. Replaced all drain hoses (clear ones) with new hoses.
  • New Filter. Replace with newer filter (Blue brand from Menards).
  • Removed and cleaned Flame sensor with emery cloth. Re-install flame sensor.
  • Put every thing back into it's place and start it over at step 1 thru 6.
  • Got the same result as step 1 - 6.

Decide to try some of the things that other people tried in this forum:

  • Unplugged the black hose that runs from the pressure switch to the burner box and the gas valve.
  • With it unplugged at the pressure switch, the furnace works But as soon as I plug it back in it shuts down and blink 3 times. I tried to do this (plug and unplug the black hose for several times) to see if anything may coming out of it. No difference in result.
  • So I left the black hose unplugged to keep the furnace running.
  • It runs for 5 minutes and shuts down.
  • It starts again immediately and shuts down after 5 minutes later. The cycle repeats…….
  • Since we need comfort, I had it running with the 5 minutes interval until it reached 68 degree. I shut the furnace down at the breaker switch.
On 10/19/2012, I called local heating and ac places to see if they would sell me a flame sensor. Since I took it out and sanded it, I thought I may some how broke it. I figured why not doing that first before I call for a tech. Well, I found out the hard way. No one were willing to sell it to me. Not the tech, the general contractors, parts suppliers, etc. I have to be license to buy it. I felt like I have to be inducted into the mob to buy a flame sensor. Long story short, I went home on a Friday night without a fix. Luckily, the temperature was about 20 degrees above normal. We added more blankets to the beds for comfort until I can and willing to look at it on Saturday morning. Meanwhile, on Friday, I called a Trane salesman to give me a quote for a new furnace since mine is old (less than 10 yrs) and the problem might be the heat exchanger. He said he would stop by or call me in on Saturday but he never did. I don't feel like going back to a Trane furnace.


Saturday morning,
  • Replaced all drain hoses (clear ones) with new hoses.
  • Remove the drain trap and cleaned with tooth brush and dawn detergent.
  • Check continuity between wires at the pressure switch, limit switch, flame sensor, and gas valve. Just wanted to make sure that they have good connections.
  • Put every thing back together and flipped the breaker back on.
  • 1. Set thermostate to heat
  • 2. Set temperature 6 degrees above room temperature. Room temperature was 64 degree. Set thermostate temperature to 70 degree.
  • 3. While I was in the main floor I heard the exhaust fan (Inducer) comes on. I didn't bother going back to the furnace. I figured I was done playing around with it. If it didn't work, I will get a new furnace.
  • 4. Moment later I heard the flame kicked in and then the main blower came on. I told my wife to mute the TV. She said, "Why"............I was w
  • 5. 5 minutes later, I heard the flame shuts off. I put my hand over the vent and felt the cool air coming out. I said, "shiiiiit". The inducer shut down. About 30 seconds later the Inducer came back on. The flame kicked in and then the main blower came on. I went to the thermostat and increased it to 72 degree. "We'll see if it stays on", I told my wife as she served the net on her laptop.
  • 6. The furnace never shut down and cycle. It reached 73 degree and turned off.
  • It's been warm in and out of the house I haven't heard the furnace coming on. I also have the thermostat programm to 65 degree at night, 60 day, and 68 while we are at home.
  • I will try to kick it up again when I get home tonight just to check and validate the fix.
  • I think the fix is by cleaning the trap, a while plactic container that had 3 clear plastic hoses connecting to it.
 
  #7  
Old 10-22-12, 08:49 AM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,245
Received 0 Votes on 0 Posts
Remove The other hose of the pressure switch (not the one you disconnected) at the connection to the cold end header of the heat exchanger (beside a big drain hose that goes to the trap) . Make sure that port is clear by insertingthe a paper clip and reaming it out.
 
  #8  
Old 10-26-12, 11:13 AM
Member
Thread Starter
Join Date: Oct 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
I'm happy, literally, to report back that the furnace is working without a hiccup with the cleaning the trap, a while plactic container that had 3 clear plastic hoses connecting to it.


 
  #9  
Old 10-27-12, 05:34 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Received 0 Votes on 0 Posts
Hello, I'm from Rochester too! Too bad I didn't see this sooner! I was going to say, check that trip. I've seen that plugged with lady bugs that we've had here in the past!
 
  #10  
Old 02-11-13, 01:48 PM
Member
Thread Starter
Join Date: Oct 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Well, my furnace is doing the same thing again, erratic on and off with 3 blinks error code (pressure switch).
The heat didn't kick in this morning at a programmed time, 6:00 am due to this error.
Got it to run and reached set temperature of 67 degree by turning off power at the breaker and cleaned the trap, and checked pressure switch with light blow; it clicks.

This afternoon at around 3PM, furnace came on and stop short of set temperature (67 degree) due to pressure switch error.
I turned off power at the breaker and checked the pressure switch with light blow into the switch with my mouth. Switch is clicking fine. I cleaned the small pin hole of the insert of the pressure switch with a small paper clip. I didn't see any blockage. Restarted the furnace and it is running reaching 69 set degree. If the error repeats, I will try to replace the pressure switch. I'm not giving up on this furnace yet.
 
  #11  
Old 02-11-13, 01:54 PM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,245
Received 0 Votes on 0 Posts
95% of the time it is NOT the pressure switch, but you could have ruined it by inserting an object into it.:NO NO NO:

You need to make sure the intake and exhaust are clear, you also need to make sure there is nothing stuck in the drain hoses that lead into and out of the trap. Other possibilities are a weak inducer or failed heat exchanger.
 
  #12  
Old 02-12-13, 03:33 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
Yes, replacing the pressure switch is almost always a waste of time and money.

It is FAR more likely that the pressure switch is opening for a reason, usually because something is plugged up in the furnace or venting system.
 
  #13  
Old 10-16-13, 12:20 PM
Member
Thread Starter
Join Date: Oct 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Well, it is that time of the season again. Furnace is not working again. Well, I guess it was never been fixed...........Time for a new furnace.
 
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: