TRANE XB80 no heat!

Hello folks! Yesterday after coming home from work I noticed the house was a bit chilly. Noticed air was being blown but it was only cold air.

The following is what I know and what I have looked at.

  1. Heat is commanded vent motor fires up. After about 6 seconds vent motor shuts off and main fan blower kicks on. No flame, no ignition…

  2. Error LED flashes 6 times. Supposed to mean 115VAC reveresed polarity or bad ground.

  3. I checked all powerI have 120VAC.. getting to the circuit board. I have 120VAC on Primary of transformer and 27VAC on secondary being fed to CB.

  4. I have no voltage ever getting sent to Gas valve or ignitor. Have clean filter shorted out safety switched one at a time same results.

This one is bugging me I am not sure what the cause would be… I am thinking it may be the Circuit board but I don’t know. About ready to give in and call HVAC tech but any other advice would be welcome.

Regards,
Tom Spokane, WA

http://www.aireng.com/clientuploads/Trane_Data_Guides/Furnace/tuy.pdf

6 blink codes is from the control board indicating the problem… Computer never lie. Check your ground and polarity.