Armstrong gas furnace won't start


Hi,
I have a Armstrong Air Ultra V - Tech 80 furnace with a Honeywell Smartvalve II SV9520H which doesn't start. Here are the details about the problem:
1. When the thermostat is on the OFF position, the led indicating the status is showing the normal function "heartbeat" 2. Turn the heat on the thermostat (80 F) and set the thermostat to AUTO - nothing happens, the furnace won't kick off. 3. Set the thermostat switch to ON - the blower kicks off but the gas won't light. After about 20-30 seconds, the status led starts flashing 3 times which means: "Presure switch open. Should be closed".
NOTE: The gas is on and the furnace turned on from the main switch.
Any idea of what might be wrong with the furnace and how can I solve the problem?
Thanks, ne@
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guessing: on my non electronic boiler, the exhaust from the combustion is blown up the flue to the chimney and a silicone tube connects the suction port of the flue blower motor to a switch. the switch tells the controller it is ok to light the gas main, with power off, i disconnect the hose and poke the suction port nipple with a paperclip to clear its blockage.
ne@ wrote:

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Sounds like the purge blower is out. A call for heat should bring on the (purge blower) blower on the flue and purge the furnace before the ignition system lights the burner. If the purge blower comes on then fails to go to ignition, then look for flue obstructions or bad blower wheel.
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see also similar thread at: http://www.hvacmechanic.com/forums/resservice/messages/21908.htm#0
ne@ wrote:

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ne@ posted for all of us...

Google is broken at your house? This has been addressed SO MANY times.
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Tekkie Don\'t bother to thank me, I do this as a public service.

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That sounds right jolt. I just realized the blower is not working. That's the reason the pressure switch doen't get closed, there is no suction on the hose to close the switch.
I checked the switch and works perfectly.
First, I hear some noise inside and I thought the blower started, but no, the BLOWER WON'T START.
Any of you guys have any idea how ca I troubleshoot/fix this?
Thanks, ne@
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For a draft inducer fan not working, the usual answer is to check for power getting to the fan. If power, then replace the inducer fan. They are a fairly common part.
If the inducer runs, but the vacuum switch doesn't operate, check for clogged or blocked combustion air tubes. Bees nest in the exhaust?
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