On 12/22/2014 1:51 PM, Danny D. wrote:
trader_4 wrote, on Mon, 22 Dec 2014 08:37:51 -0800:

No, they are talking about polarity reversed at the incoming AC,
ie hot and neutral. How would you ever get DC reversed on the circuit
board?

The incoming power, at least at the BX cable coming into the furnace,
is not reversed, but, clearly "something" is wrong, so I do
appreciate the advice as to what to look for.

A few things I did in the meantime, which "may" have changed the
situation is that I opened up all the vents in the house, most
of which had been closed for some reason (almost certainly since
last winter), which means the vent airflow was certainly stifled.

I opened all the suckers:
https://c4.staticflickr.com/8/7563/1...ca4af62b_b.jpg

And all the blowers:
https://c4.staticflickr.com/8/7478/1...a422228b_b.jpg

And, I ascertained that there is no V-shaped filter in the top
(left) side of the furnace itself:
https://c4.staticflickr.com/8/7491/1...8312f3fe_c.jpg

This lack of v-shaped filters is apparently normal, as it is
described on the furnace cover sticker, which says:
"Horizontal furnace: Filters are located external of furnace.
Consult installer for location."
https://c4.staticflickr.com/8/7474/1...0f645731_c.jpg

Interestingly, since most of the vents were closed, I might assume
the furnace had shut off due to lack of air, but I can't find
what the sticker also says is the "RESET" button:
"Auxiliary limit control may be located on blower housing or
top of furnace. To RESET, push button on control firmly.
Refer to USERS MANUAL for more information. Call qualified
serviceman if failure continues."

Also, the sticker talks about a "fusible link", which I also
haven't found yet:
https://c1.staticflickr.com/9/8575/1...a6bf6b65_c.jpg
"This furnace is equipped with a fusible element or manual reset
limit switch in burnder compartment and/or draft diverter to
protect against overheat conditions that can result from
inadequate combustion air supply or blocked vent conditions."

Just in case, I hit all the reset buttons I could find, starting
with the two manual limit switches:
https://c4.staticflickr.com/8/7496/1...acc7329a_c.jpg

When I press the brown button on the manual limit switch, nothing
happens (I had expected a spring-loaded type of interaction):
https://c4.staticflickr.com/8/7490/1...550d1ee2_c.jpg

I pressed the brown button on the blocked vent tube switch:
https://c4.staticflickr.com/8/7580/1...19b8f191_c.jpg

There were no buttons on the flame sensor and hot surface igniter,
so, I merely wiggled the wires to ensure they were on snugly:
https://c1.staticflickr.com/9/8651/1...7fe7ca9f_c.jpg

I suspect this is the backside of the fusible link, which likewise,
I wiggled the wires to ensure they were on tightly:
https://c4.staticflickr.com/8/7498/1...4fb55b63_b.jpg

I also flipped the on-off switch, on the gas valve itself, a few times:
https://c1.staticflickr.com/9/8681/1...d011aced_c.jpg

I also wiggled all the wires and connections on the control board:
https://c1.staticflickr.com/9/8631/1...4bb7c59e_c.jpg

I'll run another series of tests, and see if any of that made
a difference.




Might have been someone, suggested low air
flow, and a bad limit switch. Trader, was
that you?

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Christopher A. Young
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