Trane XB80 error code 4 and no ignition, Limit switch OK!
#1
06-06-15, 11:21 PM
Trane XB80 error code 4 and no ignition, Limit switch OK!
Hello
I have Trane xb80 furnance blowing cold air, I opened the panel and I found the red light blinking 4 times. Everything else is working except no ignition.
I did some research and found that it's Open Limit Switch Issue. I located the temperature limit switch, tested it continuity test by the multimeter and it's working (sound peeps with the test). I couldn't find any reset buttons, so I turned off the circuit breaker and the gas, then turned them back on, same issue!
I tested the pressure limit switch and from the google'ing, I figured out that it the continuity test should fail when the furnance is off, and it was OK! I turned the furnace back on, did the same test and it peeps (so it should be OK).
Moreover, I tried to measure the voltage between the temperature switch prop and the screw, but found zero voltage.
I'm new guy in do it yourself, but I'm trying to learn. It was super expensive to pay a technician to show up starting at $150 per hr!!!
If it's easy fix, I would like to learn it...is there anyone who can help me?
Here are some photos from inside my panel to help keeping our language close.
Thank you
I have Trane xb80 furnance blowing cold air, I opened the panel and I found the red light blinking 4 times. Everything else is working except no ignition.
I did some research and found that it's Open Limit Switch Issue. I located the temperature limit switch, tested it continuity test by the multimeter and it's working (sound peeps with the test). I couldn't find any reset buttons, so I turned off the circuit breaker and the gas, then turned them back on, same issue!
I tested the pressure limit switch and from the google'ing, I figured out that it the continuity test should fail when the furnance is off, and it was OK! I turned the furnace back on, did the same test and it peeps (so it should be OK).
Moreover, I tried to measure the voltage between the temperature switch prop and the screw, but found zero voltage.
I'm new guy in do it yourself, but I'm trying to learn. It was super expensive to pay a technician to show up starting at $150 per hr!!!
If it's easy fix, I would like to learn it...is there anyone who can help me?
Here are some photos from inside my panel to help keeping our language close.
Thank you
#5
06-07-15, 02:34 PM
@ goldstar
no glow at all like there is nothing trying to ignite.
The inducer motor (I think the one in pic #3) is running all the time when calling for heat.
Any Thoughts? Thank you
no glow at all like there is nothing trying to ignite.
The inducer motor (I think the one in pic #3) is running all the time when calling for heat.
Any Thoughts? Thank you
#6
06-07-15, 02:57 PM
Your right no reset on that furnace. Are you pulling the wires off the switches to test them?
should I? I tested all of them while running and when circuit breaker is off. Thank you
#9
06-07-15, 04:50 PM
There should be one more safety switch in there. Trace the yellow wire marked YL/5 from the control board to see if you can find it.
#10
06-07-15, 05:31 PM
If you follow the flexible plastic hose coming from the inducer blower, it will lead you to a vacuum switch.
You need to see if that switch is closing with the inducer running. If not, check for crud in the hose or the nipples where the hose attaches to the blower and vacuum switch. That switch must close before power is applied to the HSI. If it is working properly, the next step is to check for a bad HSI.
You need to see if that switch is closing with the inducer running. If not, check for crud in the hose or the nipples where the hose attaches to the blower and vacuum switch. That switch must close before power is applied to the HSI. If it is working properly, the next step is to check for a bad HSI.
#11
06-07-15, 05:34 PM
I couldn't find any wire labeled YL5. I looked again and I found a switch with 4 wires in it (one blue one red on each side of it), but I don't know how to test this one.
Photos are below
Photos are below
#12
06-07-15, 05:41 PM
I tested that switch in pic #5, it fails when the inducer not working (no peep) however when the inducer is working, it peeps (which I think it should be good??). Note, I tested it with the wires on, should I remove them for the continuity testing?
Where is that HSI? and how can I make sure it's the defective peace? does it make sense ti have error code 4 with this HSI defective?
Thank you
Where is that HSI? and how can I make sure it's the defective peace? does it make sense ti have error code 4 with this HSI defective?
Thank you
#14
06-07-15, 07:00 PM
That is a transformer, not likely your problem. I think I would start to test the switches for voltage. Use the furnace chasis for ground and other probe on each side of the switches. This will be 24V.
#16
06-07-15, 07:31 PM
Did you reconnect the transformer? Can you post a close up pic of the wiring diagram? I want to make sure it matches mine.
#20
06-07-15, 08:18 PM
Can't find any thing for that model. The diagram I have shows a reverse flow switch. On the control board find the 12 connecter. Trace the yellow wire to this switch.
#21
06-07-15, 08:26 PM
the 12 connector (with 3 empty slots, so there are 9 wires only) has 2 yellow wires. One goes behind the panel (can be seen at picture #1) and the other goes to the pressure switch. Is it helpful? I appreciate your help! Thanks
#22
06-08-15, 04:01 AM
Yes that helps, trace the yellow wire that goes behind the panel. Check for voltage at that switch.
#25
06-08-15, 08:46 PM
It goes somewhere behind the panel. I can't see.
I guess it's the time for a technician! got frustrated!
Anyway thank you Sir for your help! Appreciate it!
I guess it's the time for a technician! got frustrated!
Anyway thank you Sir for your help! Appreciate it!
