Amana Air Command 80 Gas Fired Furnace (4 blinks) troubleshooting

 Can you help me troubleshoot my Amana Air Command 80 gas-fired furnace?

1. Today it stopped heating the house; three red blinks were visible.
The instructions say this means the "pressure switch is stuck open".

2. I could see the "top" (smaller" motor wasn't spinning) but the bottom
(bigger) motor was spinning; so, I guessed, there was no vaccum to the
pressure switch - hence - the pressure switch was stuck in the open (off)
position.

3. To test, I removed the hose from the top (smaller) motor & sucked on it.

4. This self-induced vacuum caused the diaphram to move which caused the
mechanical switch connected to the pressure valve to close (I could see the
switch move when I sucked on it).

5. The flame ignighter heated up and the gas started burning.
The three blinking red LED signal went out; I thought I "fixed" my furnace.

I cycled the power a few times while I cleaned the filters and blew dust
from around the wires.

But ...

6. Then the Amana Air Command 80 gas-fired furnace stopped heating again;
this time, four red blinks were visible!

7. Now the opposite ocurred; the "top" (smaller) motor was now spinning but
the bottom (big) motor was not spinning. No air was circulating through the
house.

8. Four blinks indicate an "open Limit Control (primary or auxilliary)".

8. If I cycle the power to the furnace, it works for about ten minutes and
then the bottom (big) motor stops spinning and the four blinks start again.

I have a few questions:
a) How can I troubleshoot this Amana Air Command 80 gas-fired furnace?
b) Is there a reset switch somewhere?
c) Is there a maintenance guide on the web somewhere?

Thanks,
Donna

 
Literally, the instructions say:

<quote>
Pressure Switch Stuck Open
If, after the vent blower is energized, the pressure switch does not close,
the congtrol will keep the blower on and wait for the switch to close. The
diagnostic light code for this problem is three short flashes followed by a
pause. The probable cause is either:
a) disconnected hose to the pressure switch,
b) faulty pressure switch or wiring, or
c) restricted air intake or flue piping.
<end quote>

By pulling the vacuum hose off at the top (smaller) motor side, and sucking
on it, I was able to see the pressure switch diaphragm moved and the
electrical contact closed, causing the heating element to heat up and the
gas to start. So, I could tell the hose was OK (a) and the pressure switch
(b) seemed ok.

That leaves (c).

Can you advise me what it means to have "a restricted air intake or flue
piping"?

Where do I look and what do I do to unrestrict an air intake or flue
piping?

Thanks,
Donna

  wrote:

If I were you, I would call a professional repair person to deal with
this problem. You are asking about a piece of equipment that could cause
serious damage to your home and death and injury to you and your family
if you mess with it and screw something up. Call a professional heating
and repair person to fix the problem.

 On Thu, 24 Jan 2008 07:18:07 -0500, Shawn Hirn wrote:

I did. He'll be out here on Saturday. Isn't there ANY maintenance a
homeowner can do themselves?

I'm sure, from the symptoms, that the "limits" kicked in, probably due to
some problem with air circulation.

Besides the filter (which was very dirty but I replaced it yesterday), what
other maintenance can I do.

For example, someone said clean the A/C coils ... but WHERE ARE THEY?

The furnace is in a tiny closet. The AC fan is outside the house.

Donna

 On Thu, 24 Jan 2008 17:14:29 GMT, "Donna Ohl, Grady Volunteer


Leave it alone.  Let the pro fix it.
You can ask him about what you can do with the maintenances.
Just keep your pipes from freezing until he gets there.

--Vic