Armstrong Ultra SX-90 - Contractor Talk - Professional Construction and Remodeling Forum

Leo D · 02-12-2008, 02:22 AM

Armstrong Ultra SX-90
Need help too:
My Armstrong Ultra SX-90 Furnacehas a problem:
here is what happens
1 power vent blower goes on
2 hear a click and ign lights and burner lights
3 after a second hear a click and burner goes off
4 after another second burner lights again and then click goes off
5 when I shut off power to unit and reset, it might work for a cycle or 2
Thanks for any help

hf05 · 02-12-2008, 08:48 AM

lazy [ dirty ] pilot flame not impinging on sensor and or sensor itself

Leo D · 02-12-2008, 08:26 PM

thanks, I'll try that

tdavis · 02-13-2008, 01:37 AM

our HVAC guy usually hits the flame sensor with a light emery cloth and it fixes the flame sensor problem...

Leo D · 02-14-2008, 04:26 AM

Thank you all
Here is what I did.
1 Cleaned flame sensor lightly with a nail file, very hard to get at.
2 Then I saw a burnt mark near a resistor on the curcuit board and start to clean and wiggle it.
3 replaced covers and reset unit and has been working for the last 18 hours