Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 10-20-2010, 01:48 PM   #16
Newbie
 
Join Date: Oct 2010
Posts: 18
Share |
Default

Trane XR90, LED flashes 2 times for error


On a whim, I decided to replace the ignitor. That did not seem to help. There is still no flame and the ignitor shuts off after 10 seconds or so.

I know at this point this should be a separate thread. Sorry.

Any thoughts?

theob is offline   Reply With Quote
Old 10-20-2010, 03:33 PM   #17
HVAC / Plumbing
 
Join Date: Feb 2009
Posts: 1,801
Default

Trane XR90, LED flashes 2 times for error


Quote:
Originally Posted by theob View Post
On a whim, I decided to replace the ignitor. That did not seem to help. There is still no flame and the ignitor shuts off after 10 seconds or so.

I know at this point this should be a separate thread. Sorry.

Any thoughts?


I would make sure the ps is staying closed & check the other parts of the 24v circuit. If it fires up & goes back off could be ps or flame sensor , bad ground, board
kenmac is offline   Reply With Quote
Old 10-22-2010, 12:13 PM   #18
Newbie
 
Join Date: Oct 2010
Posts: 18
Default

Trane XR90, LED flashes 2 times for error


i assume 'ps' means pressure switch? i really don't know that much about furnaces other than what I see when i take the front panels off and what I can gather off the internet. Is there a good parts list or service manual that I could possibly find?

I would test the ps to make sure it's closed (shouldn't it be open in the beginning?) but I'm not exactly sure which part this is. I would guess that it's the piece right off the main gas line coming in, but I can be sure. I'm also not sure how to test to make sure it's open or closed. any advice?
theob is offline   Reply With Quote
Old 10-22-2010, 12:38 PM   #19
HVAC / Plumbing
 
Join Date: Feb 2009
Posts: 1,801
Default

Trane XR90, LED flashes 2 times for error


It has a small hose from it to the exhaust motor. Sometimes that small port at the exhaust motor will clog up. Have you checked for 24v at the valve when this happens ? You need a vm to start checking for voltage. Did you ever find out what the error codes were ?

Last edited by kenmac; 10-22-2010 at 12:51 PM.
kenmac is offline   Reply With Quote
Old 10-23-2010, 06:06 PM   #20
Newbie
 
Join Date: Oct 2010
Posts: 18
Default

Trane XR90, LED flashes 2 times for error


i checked the pressure switch while the furnace was off and it appeared open (infinite resistance on the multimeter). i did not bother firing up the furnace because i thought that the pressure switch should be closed (close to zero resistance) when the furnace is off. is this correct? and if so, does it look like my pressure switch needs replacing? can i verify this by temporarily putting a jumper wire from one terminal to the other on the pressure switch and firing the furnace up to see if the flame lights and stays on?

on a side note, there is no pressure hose from the exhaust fan. just one from the gas valve (i believe that is what it is), one from the combustion chamber, and the final leg to the pressure switch.

assuming the pressure switch is bad, i am wondering if the fact that the condensate hose was jammed down the drain was what was causing the issue. i will be putting in a condensate pump shortly anyway.

thanks for the help.
theob is offline   Reply With Quote
Old 10-23-2010, 06:39 PM   #21
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,382
Default

Trane XR90, LED flashes 2 times for error


Should be open when the furnace/inducer is not running.
beenthere is online now   Reply With Quote
Old 10-23-2010, 06:55 PM   #22
Newbie
 
Join Date: Oct 2010
Posts: 18
Default

Trane XR90, LED flashes 2 times for error


just after i posted last i found a few sites that said that the pressure switch should be open when the furnace is off. i turned the furnace on and the resistance jumped to zero and stayed there. i did pull the condensate tube out of the drain but that didn't seem to do much either.

i did finally check the voltage to the gas valve. i pulled the two wires off of the valve and read from the red wire to ground somewhere in the furnace. it read 0 volts when the inducer fan started, and stayed at zero when the ignitor came on. the ignitor glowed for 10 secs or so, like normal, and then there was the audible click from the lower area near the circuit board (i believe) and the ignitor turned off. around this time, i read about 26.5 volts from the red wire for a few seconds and then it went away.

any ideas?

ps - the original error code was two flashes of the diagnostic light (System lockout (retries or recycles exceeded))

Last edited by theob; 10-23-2010 at 07:15 PM.
theob is offline   Reply With Quote
Old 10-23-2010, 06:58 PM   #23
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,382
Default

Trane XR90, LED flashes 2 times for error


Could be the switch, is opening while the burners are lite. This can be a bad switch. or an obstruction in the vent pipes.
beenthere is online now   Reply With Quote
Old 10-23-2010, 07:21 PM   #24
Newbie
 
Join Date: Oct 2010
Posts: 18
Default

Trane XR90, LED flashes 2 times for error


Quote:
Originally Posted by beenthere View Post
Could be the switch, is opening while the burners are lite. This can be a bad switch. or an obstruction in the vent pipes.
it could be the pressure switch? the burners have never lit. the ignitor always glows and then shuts after 10 secs or so. no flame.

the switch could be bad even though there is no resistance between the terminals when the furnace is running? although i did find that while there was no resistance between the two terminals with the wires still attached, and there was 24v+ going from each lead/wire to ground, there was no voltage between the two leads/wires. i don't know if that means anything or not.

i did check the small pressure hoses and there didn't seem to be any obstruction. there was no obstruction that i can see on the intake pipe/grate, but I haven't checked the exhaust fan. it that necessary?

thanks for the help
theob is offline   Reply With Quote
Old 10-23-2010, 09:45 PM   #25
HVAC / Plumbing
 
Join Date: Feb 2009
Posts: 1,801
Default

Trane XR90, LED flashes 2 times for error


Don't read resistance .. read voltage. If the switch is colsed . you won't read volts connecting vm terminal to terminal. If the switch is open you will read voltage
kenmac is offline   Reply With Quote
Old 10-24-2010, 03:16 AM   #26
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,382
Default

Trane XR90, LED flashes 2 times for error


Its not the switch if its not lighting, and the ignitor is glowing.

Check for 24 volts across the gas valve.
beenthere is online now   Reply With Quote
Old 10-24-2010, 02:19 PM   #27
Newbie
 
Join Date: Oct 2010
Posts: 18
Default

Trane XR90, LED flashes 2 times for error


Quote:
Originally Posted by beenthere View Post
Its not the switch if its not lighting, and the ignitor is glowing.

Check for 24 volts across the gas valve.
the ignitor is certainly glowing and the furnace is not lighting. i did check the gas valve yesterday and i believe it might not getting power, though i am not entirely sure of how it's supposed to power up.

to check the voltage to the gas valve, this is what i did: i pulled the two wires off of the gas valve and started the furnace up. i then checked the voltage from the red wire to ground somewhere in the furnace and watched it for the first minute while the furnace started up. i read 0 volts when the inducer fan started, and it stayed at zero when the ignitor came on. the ignitor glowed for 10 secs or so, like normal, and then there was the audible click from the lower area near the circuit board (i believe) and the ignitor turned off. around this time, i read about 26.5 volts from the red wire for a few seconds and then it went away. i believe i also checked the black wire for voltage as well, but i didn't get anything.

is this a gas valve problem? a circuit board problem?

as a bit of background info, the furnace came with the house when i bought it a couple of years ago. i believe there was a flood at some point because the bottom of the furnace is pretty rusty (and the previous owner mentioned something about not hooking up the condensate drain properly or something like that). from what i can see, the water damage is only confined to the bottom of the furnace and it's metal walls and floor. the circuit board seems fine and the furnace ran fine for the past couple of winters. might there be a problem there?
theob is offline   Reply With Quote
Old 10-24-2010, 02:26 PM   #28
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,382
Default

Trane XR90, LED flashes 2 times for error


Check for voltage between the 2 wires that are connected to the gas valve, while they are attached to the gas valve.

If you don't get 24 volts across the gas valve, but do when you read red to ground. Most likely. You have a limit or roll out switch open somewhere.
beenthere is online now   Reply With Quote
Old 10-24-2010, 02:30 PM   #29
Newbie
 
Join Date: Oct 2010
Posts: 18
Default

Trane XR90, LED flashes 2 times for error


thanks. i will check now. i believe i checked the high limit switch, but i am not sure where the roll out switch is located.
theob is offline   Reply With Quote
Old 10-24-2010, 02:42 PM   #30
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,382
Default

Trane XR90, LED flashes 2 times for error


Somewhere around the burner box. May be more then one.

beenthere is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Trane XR90 Pressure Switch Error kenk HVAC 30 10-10-2012 03:24 PM
Trane XR90 Mike2401 HVAC 32 12-22-2009 01:18 PM
Trane XE 80 4 flashes on board Trane Spotter HVAC 1 11-13-2008 07:58 PM
Trane 80xl, 3 flashes error light - draft pressure problem, help? Xsta HVAC 1 10-14-2007 08:20 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.