Greg, again thanks for your input. They have had meters on several of
the circuits, but never had anything but normal readings. At the time,
though, the furnace was functioning normally. It did fail twice while
they were here, but they didn't have a meter hooked up at the time.
One tech looked at the other at the first of the failures and said, "no
gas." That's what caused them to put in a new valve. But within a
day, I was having lock-outs again.
I think they're now grasping at sraws, however. They suspect a problem
with the composition of the LP gas, and pointed to the green residue
on the flame sensor. I don't see how that has anything to do with the
ignition failures, particularly after you described the cycle to me.
There certainly is no problem with the gas water heater sitting right
next to the furnace.
Bubba, I have not paid anything for any of the parts or labor except
for the first service call six weeks ago, or so. The furnace is only
28 months old and I have a ten year-warranty. I am concerned, though,
that with their expressed concern about the quality of the LP gas, that
they may be very frustrated and starting to "bail out" on me.