Jump to content
Click here to check out our structured, online appliance repair training courses for rookies and experienced techs.

FAQs | Repair Videos | Academy | Newsletter | Contact


DISCLOSURE: We may earn a commission when you use one of our coupons/links to make a purchase.
  • Upcoming Events

    • 30 March 2024 02:00 PM Until 03:00 PM
      0  
      All Appliantology tech members are invited to join in this workshop on all things Appliantological: bidness, customers, tools, troubleshooting, flavorite brewski, whatever. Webcams and microphones are open and live!
      This workshop is also a great time for any students at Master Samurai Tech to bring any and all questions about the coursework. We're happy to walk through any concepts you're having trouble with. Think of it like office hours with your teachers. 
      If you have a specific appliance problem you'd like us to talk about, post it here! We need a problem statement and a PDF of the tech sheet or schematic so we can all see it on screen share. If you have a PDF that isn't already in the File library here at Appliantology, send it to us by attaching it to the contact form. 
      Also, follow this Calendar Event so you'll get notified of new posts here. Look for the "Follow" button either at the top of the topic on desktop or below the topic on mobile.
      Who: This workshop is only available to tech members at Appliantology.
      When: Saturday, March 30 @10:00 AM Eastern Time.
      Where: Online via Zoom
      How:
      Click here to go to the forum topic with the registration link. If you're interested, register now. Arrive a couple minutes early to make sure your connection is working. Set a reminder for yourself for this workshop so you don’t miss it.  And check out past workshops here: https://appliantology.org/announcement/33-webinar-recordings-index-page/

trane furnace blu108e936b1 blower stays on continuously


mwfarrar1

Recommended Posts

This is an old 1983 trane gas furnace that the blower stays on all the time. I checked the thermostat and the fan runs in every setting. I am thinking a bad relay from what I have read on the internet. Any help would be appreciated. I have never worked on a furnace before except to replace the thermostat a few years back.

Link to comment
Share on other sites

  • Replies 2
  • Created
  • Last Reply

Take the face off of the T-stat if it is a digital programmable and see if the unit still runs the fan.  If it does, turn off the power to the air handler (with the t-stat face still off) wait a few seconds and then turn it back on.  If the fan comes on again, suspect a stuck relay.  If the T-stat is one that is other than a digital you can turn the Fan off and the Mode to off as well.   You can also remove the R terminal from the sub base and see if the fan continues.  These are non-technical ways to check for the problem

The technical way to test and confirm a bad relay requires a meter set to volts.  With the unit powered up, check for 24 VAC from the G terminal to Common at the control board or where the T-stat wires enter the furnace case and are wire nutted to the unit's low volt wiring.  If you have 24 volts with the T-stat turned off and Fan off, you will have to check for a wire to wire short in the 18/8 pairs between the T-stat and Air Handler or a poor terminal connection at the T-stat or board.

You can check the fan relay itself (if it is in fact a relay not located on a control board) using Continuity on your meter across the N.O. contacts with the unit off.  If there is continuity on otherwise N.O. contacts, then they are stuck and the relay should be replaced.

Let us know....best of luck.

Link to comment
Share on other sites

Thanks for the info. I believe I found the problem to be the fan limit switch. I went back and looked at a post that talked about the limit switch. With the power on, I turned the dial and got the fan to shut off.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.


×
×
  • Create New...