Built in 8-06, this thing is pre FVIR, Power vent...Hot shot.
Go on a no hot water call.It is flashing the classic '6' error code so I clean the flame sensor rod,put all back and it fires after *tightly* putting the inner and outer doors back on.
I was called 3 days later same thing.
Show up and it's running?!Thought ok....
Called back in 2 days..failed again.
Well turns out that it is now intermittent.
Is the flame sensor out of specs?
I called tech support and they were already gone for the day.
I install Rheems.