Hello
Been looking at various problems with the concord.
Most seem to be limit switches.
Problem with mine is the small side hose from exhaust blower
To switch is accumulating about inch of water in it
And is shutting furnace down.
Once tube is drained she fires up and
Runs for 2 days then does same thing all over again.
What would be causing tube to accumulate too much water?
Everything else aok.

Check the condensate drain line for restrictions.