Furnace Problem Fan Related - HVAC - DIY Chatroom Home Improvement Forum

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


Thread Tools Display Modes
Old 03-12-2013, 03:41 PM   #1
Join Date: Mar 2013
Posts: 2
Rewards Points: 10

Furnace Problem Fan Related

Hello all,

Here's what I got. Two days ago the house got up to 74 and I tried to turn the air on. The compressor was running but the blower motor never started. By time I realized the house was still warm, the compressor was a block of ice and I shut it off. I was busy and couldn't wait for it to thaw and check for problems. Soooo, its ohio, I tried to turn the heat on last night, plenty of fire, the fan still does not run.

The fan does not start if you set the fan to ON. I opened the furnace and checked the capacitor, tested A OK. I taped the door switch shut and started checking a few voltage points, where I checked was good. I turned the HEAT on and switched the fan to auto. I have fire, I'm testing more points watching the limit switch creep up. Then the limit switch made a tiny bang (like a coil that was bound up released,) then the fan turned ON. I stopped where I was and let the house get up to 70, it was down to 59 by time I got this far. It cycled the fan on and off multiple times to warm the house up, seems like the air temp was a little cooler than it wanted coming in. Fan still does not work when set to ON.

I'm having a mental breakdown I think. I'm assuming at this point the limit switch is bad and needs replaced, but does this have anything to do with the switching the fan to ON? And how does this relate to the blower not running when set to AIR? Could half of the limit switch short out and cause this?

I know you guys want details, but I honestly cant tell you exactly what furnace it is lol. It appears that this furnace is sold as about 40 different manufactures. This is the model on the sticker, PCMU-LD16N095B.

Any help you guys can provide will help me immensely.


LocalSimpleton is offline   Reply With Quote
Old 03-12-2013, 04:00 PM   #2
Hvac Pro
yuri's Avatar
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 15,981
Rewards Points: 100

post some pics and closeups of it with both doors off and the model # sticker.


"Cut it twice and it is still too short".
yuri is offline   Reply With Quote
Old 03-12-2013, 04:24 PM   #3
An old Tradesmen
Join Date: Oct 2008
Location: Somewhere
Posts: 34,402
Rewards Points: 7,794

Generally wouldn't be a limit switch problem if the fan doesn't run when you set the fan switch to on at the thermostat.
beenthere is online now   Reply With Quote
Old 03-12-2013, 06:24 PM   #4
Join Date: Oct 2011
Location: PA
Posts: 5,918
Rewards Points: 582

pics it needed .....but to me it sounds like you are watching a fan and limit combination control...ben sr
ben's plumbing is offline   Reply With Quote
Old 03-12-2013, 07:01 PM   #5
Join Date: Mar 2013
Posts: 2
Rewards Points: 10

having issues with my camera

Cant get it to connect with usb for some reason. I will add pics another way.

Ben, do you mean you think im watching the normal operation of the furnace?

I mean, right now im stuck with, why doesnt the fan turn on when set to ON.
LocalSimpleton is offline   Reply With Quote

Thread Tools
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
Heil Furnace Burner Problem timothyr HVAC 79 02-12-2014 07:01 PM
Quote for new furnace. Reasonable? dengle HVAC 16 03-04-2012 07:01 AM
Help with furnace blower problem Spydey HVAC 6 12-15-2010 08:18 PM
Old Silver-Line furnace problem avro1 HVAC 9 03-18-2010 12:01 AM
New Cased Coil - Install to Furnace - PICTURES!! hartkem HVAC 39 11-18-2008 01:45 AM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1