Furnace Short-Cycling
2018 Furnace - Atwood/Dometic model AFSD20141 is short-cycling. I tried the following everything: Jumped the thermostat jumped the high temp limit switch jumped the sail switch removed disch...
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dougrainer wrote:BFL13 wrote:
That tongue looking thing un-screws along with the sparker unit and the orifice can then be seen. You can check that for if its hole is plugged up. Also confirm the sparker gap is correct--could matter even more for the new gap flame sensor method.
The screen on that tongue eventually rusts out in places. The furnace burning gets wonky from the flame being exposed where there is no screen anymore. You can get a new one from Amazon. Be sure to get the right part when the time comes. There are different tongues by models of furnace. Just got one for my old 8531.
This post explains where the orifice IS. When you have microscopic debris floating around behind the orifice, it gets in front of the orifice hole and blocks the LP for awhile. That is why I keep asking about the orifice. Obviously, you are confused as it seems you do not know what the orifice is. Remove the orifice and verify there is no debris in the cavity behind the orifice and the orifice hole is clear. You can use PC can air to blow it out. Now, I am almost 100% sure your problem is a bad LP regulator from your posts on the way it malfunctions. REPLACE the LP regulator and then retest. FORGET the exhaust tube system. You are not going to have a problem with the exhaust tube and parts of it. There are hundreds of thousands of this model Furnace out there with that same exact exhaust tube and NONE cause problems. Doug
That would explain why it works with the restricter out. With the restrictor in the velocity increases and would present as running out of fuel. Is this a fair assessment on what is occurring?
