"Danny D'Amico" wrote in message
news
On Tue, 10 Dec 2013 18:10:46 -0600, philo wrote:

If the blower is working that means the furnace is getting power.
Unless you know /exactly/ what you are doing, a furnace is one thing
you should not fool with.

The fact that I assume 120 volts (and whatever the high-tension leads
have in them) is there, is the key reason why I'm not just jumping
leads just yet.

I want to *measure* first. That's not dangerous. Jumping things is
much more dangerous (if I make a mistake).

So, at the moment, I concentrated first on identifying all the parts
of the furnace (which I snapped a picture of and posted separately).

Then, I am concentrating on figuring out how those parts play together.

After that, I'll do the measuring.

And then the jumping.

I'm sorry I'm probably way slower than you guys would like, but, I'm
trying to actually understand the darn thing first ... Thanks for
your patience. I've still got to read that Carrier manual ...


Check for 24VAC between SEC1 and SEC 2. If there is no 24VAC, check the
transformer solder joints on the circuit board

Leave one lead on SEC2 and check for 24VAC on the red wire terminal. If you
have 24VAC the interlocks are OK. If not, trace back until the open
interlock is found

With the stat calling for heat, check for 24VAC at the W terminal. If you
have 24VAC, the stat heat circuit is good. You should hear the gas valve
click and the igniter spark.

If you look at the schematic for 394JA you will see the blower motor relay
is normally closed. If the furnace is powered up and there is not 24VAC at
the R terminal, the blower motor will run right away and not shut off, which
is what you said it's doing (note the jumper between R and GH)