Nordyne furnace problems-Please help

Questions about repairs and parts for Nordyne furnaces, air conditioners and heat pumps for manufactured homes including Intertherm, Mac and Miller brands. Click here for Nordyne parts.

Moderators: Greg, Mark

Posts: 2
Joined: Wed Nov 30, 2011 4:32 pm

Thu Dec 01, 2011 8:21 am

I have a 5 year old Nordyne furnance (FG6RC 100C-16B) which is giving me problems. The furnace heat hasn't been kicking on beyond the inducer motor (I get 2 flashing lights indicating open switch). Over the last year or so, the furnace would periodically do this. I had a tech come out around a month ago. He replaced the pressure switch and the flame sensor. I'm having the same issues again today.

I've been able to get the furnace to work if I go through this series of items. Remove the vent exhaust PVC at the furnace, remove the pressure switch and then blowing in it to make sure the diaphram isn't stuck, replacing the switch, turning back on the furnace (without exhaust PVC attached), waiting for the unit to heat and then attaching the PVC.

This has worked the couple of times it's gone out in the middle of the night. The furnace isn't working again this morning and now this process no longer works. What I get now when I go through this process is: the the inducer motor runs, the burner box begins to light up, and then it stops and the 2 green lights begin to flash. Again, all of this happens without the exhaust PVC attached to the unit. Can someone help me diagnose this? Here are some other details which might help:

- Unit is upflow with 2 inch PVC exhaust running about 30 feet in basement (2 elbows) Someone told me the PVC could be restricted. Could this cause the switch to go bad?)
- PVC Slope looks ok?
- Pressure switch (1.74 ) was replaced a month ago (could this one be bad too)
- It's cold in here. :)

Thanks for any help you can offer.