Indicates a open limit switch
Here some info
I'm installing a used funace,, I've had it checked out by a certified guy
And we had it running while we checked it out... worked great...
Then I installed it in my house,, when I hooked it up and turned it on
The inducer comes on, and the main blower comes on
And then the led flashes 4 times,, then waits 5 secs then flashs 4 times
Continuously... ive check the wire connections, same result...

Now I'm thinking there is 4 limit switches.. right??
How do I narrow it down to which one? continuity test??
Any other ideas??
Thanks much
Like to have some heat...
Heat I good

Thanks
Bryen

Check the ones strung together with purple wires first-press the small tab in the center, if any "click" they were tripped. Don't forget the one under the blower shelf, or the one on the front of the blower (if present-look behind circuit board mounting plate). Check the main limit too (red wires, behind the gas control). If you have a voltmeter, check for voltage across each switch with the unit powered. If you measure approx. 24v, the switch is open.

Quote:

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Originally Posted by KC13

Check the ones strung together with purple wires first-press the small tab in the center, if any "click" they were tripped. Don't forget the one under the blower shelf, or the one on the front of the blower (if present-look behind circuit board mounting plate). Check the main limit too (red wires, behind the gas control). If you have a voltmeter, check for voltage across each switch with the unit powered. If you measure approx. 24v, the switch is open.

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Sweet man,, I got it running,, was just the switch under the main blower wire, was disconnected
OK,, my next question,,
Seems that when the temp has been met and is shutting down,, the main blower
Seems like it runs way to long,, and blows a lot of excess cold air
Other than that, I have wonderous heat..
Thanks for the quick response
Bryen

Is your furnace a two stage furnace? If so, there are three dip switch settings on control board. Top is for blower off time, middle is for one or two stage, bottom is for auto or five minute (first and second stage) switchover. Please let me know what you have. I can't remember what the top setting is on from factory, so if you could let me know what it says, I could try to help you out.

Where is the main limit switch