Suburban Mfg. model NT20SEQ furnace intermittent lockout

[johnbryanpeters]

The ignition and fan control board on my Suburban Mfg. model NT20SEQ furnace has taken to intermittently locking out, which leaves the blower running with no flame. Resetting it's a PITA, turn off the thermostat, pull the fuse which protects the furnace feed, replace fuse, turn the thermostat back on.

Plenty of propane, stove and refrigerator work fine. 12 VDC is at a healthy level.

Given that the problem is intermittent, it's going to be hard to diagnose further. Any suggestions?

[Johnfort]

Dinosaur Boards makes a circuit board for your furnace.