On Monday, December 22, 2014 9:30:56 AM UTC-5, Danny D. wrote:
trader_4 wrote, on Mon, 22 Dec 2014 03:57:10 -0800:

Could be some sensor input is lacking, but then you'd think it would be
flashing a code that was in the table. Given what it's doing, my first
suspicion would be that it's a bad control board. Did you put a meter
on it when power is first applied, verified that it has 120V, ground is
OK, etc?

I agree with you that the first thing I need to test is power and
control inputs.

The sad thing is that I don't have a clue how to test that, as only
once before did I ever troubleshoot a furnace. I don't even remember
if it's AC or DC control inputs. Nor which color wires do what
(although I do remember that it's a standard, so, I can look that up).

I just received from Bryant two more PDF manuals, in addition to the
sparse 12-page 373 LAV Series G "User's Information Manual" that
I had already found, namely:
a. Installation Start-up, and Operating Instructions (24 pages)
b. Service and Maintenance Procedures (16 pages)

I can convert the PDF to JPEG and then post the JPG so you can read
them, but is there a way to just post the PDF for you to view them
to help interpret them?

The thing is constantly flashing, which according to the table, is
polarity reversed. That's virtually impossible, but there could be
something wrong with the incoming AC. To test it with a VOM:

turn off power, usually via turning off the red safety toggle switch
that's mounted near the furnace.

get access to the incoming AC, remove wire nuts from hot and neutral,
but leave wires twisted together

make sure wires are in the air, not touching anything

then turn power switch back on

with VOM check for
120V from hot (black) to neutral (white).
120V from hot to ground (that tells you it's not reversed polarity and
that the ground is likely OK.
0V from neutral to ground

Then turn off power and put it back together.

You could also do it easier without removing wire nuts if you
can find hot/neutral identified on the control board. You could just
probe it there.

If you're unsure about any of that, or basic electric safety,
I agree with Stormin. Either call a friend in who is, or just call for service.

Besides, I'd bet 99% that nothing is wrong with the power.