Pellet stove won't start (St. Croix-Afton Bay) Any help is Apreciated

When I start it (on manual) the fans come on, it feeds the burn box with pellets, then the auger stops all fans shut down and the #2 & #3 lights blink simultaneously. From the time I push start until the lights start to blink and everything stops and the control board won't respond is about 45 -60 seconds. The pellets don't ignite. The ignitor is hot (presumably not for enough time to ignite).
The manual indicates this is a high limit switch problem. I've reset the switch, no change. By-passed the switch with a jumper, no change.
Now, Ive taken the stove outside and completely cleaned it (with brush, scraper, vacuum and an air compressor)- All ash traps, air intake path, exhaust path, behind the burn box, removed and cleaned both fans. The seals are in good repair. all doors and trap covers replaced and closed. I've by-passed the high limit switch, the vacuum switch, checked all the wiring connectors, cleaned the control board ground, ensured the control board is securely in place (fuse is good). I've checked the wires and voltage (at the switch and at the pin out on the control board) for the hi-limit, vacuum and proof of fire switches.
I took the proof of fire switch off and cleaned the contact area on the switch and fan.
I've by-passed the proof of fire switch. When I did this, It follows the same procedure as above except, the combustion/exhaust fan remains on after the #2 & #3 lights blink (and the auger stops and the ignitor no longer heats).
I have by passed the switches individually and simultaneously. I am at a loss as to what the problem is.
It does not seem to be completing a full start up cycle. But, since it drops pellets and the ignitor begins to heat, it has apparently passed the vacuum check. Then after approximately an additional 30 seconds it shuts down (minutes before the proof of fire check should occur).
Any suggestions are welcome. - Thank you

FIRST, I want to thank you all for taking the time to read and reply to my post.
I am going to go thru them individually and have another look at the stove.

In general, I don't think it's a venting or intake air issue. We took the stove out on the deck to completely clean it with the vacuum, compressor, wire and scrapers; and have since been testing it outside with just 18" of straight pipe off the rear of the stove and the combustion intake open right at the stove. I understand the combustion air may not be optimized, but I would still expect it to light, not shut down and stop the ignition process.

SmokeyTheBear said:

Have you cleaned your venting including the termination cap? Also is your damper open about a pencil's width? Are all of your cleaning rods fully inserted in the stove, and does your versa grate move?

Now about the flashing lights there is no diagnostic indication that uses 2 leds so which of the lights is actually flashing.

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Yes, we cleaned the vents, and are currently testing it outside without the vent pipe. All the rods are fully inserted. The versa grate moves.
The Afton Bay operations manual online (pg. 7) states that the simultaneous blinking of lights 2 & 3 is the error message for a high limit switch issue.
But, I've by passed the switch with a jumper with the same results, Plus the stove never heats up.

imacman said:

As Smokey says, it sounds like there is a blockage in the stove or exhaust system. Not enough vacuum to close the vacuum switch and therefore the auger won't turn.

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I don't think there is a blockage. I've cleaned the stove. Currently testing without the vent connected. Plus, I've by passed the vacuum switch with a jumper (1. before pressing start and 2. pressing start and waiting 15 seconds to connect the jumper). I've checked the voltage at the switch and at the control board (it's 120v one side only).
Plus in addition to running it as is, I've tried augmenting both intake and exhaust (one at a time) by blowing air in the intake and sucking thru the exhaust with a vacuum.

imacman said:

As Smokey says, it sounds like there is a blockage in the stove or exhaust system. Not enough vacuum to close the vacuum switch and therefore the auger won't turn.

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I've by-passed the switch and augmented the exhaust (see other replies) and the auger fills the burn basket with pellets before it goes into shutdown.

wwert said:

Vacuum test was not necessarily completed. Stove could even light and then shut down with number 2 light flashing. I agree with both answers above, my guess is clogged chimney. Does exhaust fan come on when it starts up?

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Yes the fan comes on and I've eliminated the chimney for testing.

mnkywrnch said:

The #2 and three lights flashing are for a fault in the high limit switch circuit,you said that you bypassed the high limit switch with the same results it can't be the room air blower because the stove never starts and so the the stoves not overheating from a weak blower,the only other thing it could be is the control panel falsely thinking the stoves overheating when it isn't.

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I do think this could be the problem but haven't found any way to do a general diagnostic on the control board or any way to "reset" the board. I have checked the pinouts on the board for the Vacuum Switch (5 volts one side only), Proof of Fire switch (5 volts one side only), and High limit switch (120 volts one side only). The tech manual says 5 volts for the vacuum and proof of fire, but doesn't indicate the voltage for the High limit. Don't know what to do next.

Tim469 said:

I don't think there is a blockage. I've cleaned the stove. Currently testing without the vent connected. Plus, I've by passed the vacuum switch with a jumper (1. before pressing start and 2. pressing start and waiting 15 seconds to connect the jumper). I've checked the voltage at the switch and at the control board (it's 120v one side only).
Plus in addition to running it as is, I've tried augmenting both intake and exhaust (one at a time) by blowing air in the intake and sucking thru the exhaust with a vacuum.

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Sorry, I meant to say 5 volts one side only.

SmokeyTheBear said:

Page 7 of the operations manual states the stove will complete a safety shutdown with a flashing #2 for a vacuum fault and complete a safety shutdown with a flashing #3 for a high limit fault or a POF failure.

The flashing number three can actually indicate the following as the cause of the safety shutdown.

1: Out of fuel.
2. High Limit Trip (this is because there will be no fuel and the POF will open).
3. Failure to present POF within start window (the POF is still open after the start window).

In short the proof of fire switch fails to close or isn't closed (this can be the case for a number of reasons most of which have nothing to do with a high temperature issue).

The controller presents the flashing number two when the vacuum switch is not closed when polled during the start up window or a period of time has passed in which the vacuum switch hasn't closed that exceeds the normal daily maintenance time allotment window (that is the amount of time needed to have the door open to do pot scrapping etc ... ).

The flashing number two can actually indicate the following as the cause of the safety shutdown.

1. Combustion blower issue.
2. Ash in the venting.
3. Ash in the vacuum tubing.
4. Ash in the barb the vacuum tubing attaches to at the stove end.
5. Incorrectly set damper.
6. Failing stove gaskets.
7. The door is open for too long a period of time.
8. A bad vacuum switch.

Most controllers can only present one error indication and page seven of the operations manual does not indicate the 2 & 3 flashing at the same time exists as an error indication.

So again I ask which of the leds is actually flashing and yes it can appear more than one is looking through that heat level indicator. I know because the controller on your stove is made by the same folks who made the one on my stove.

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Smokey, Thank you for your time and thoughtful reply. It is the 2 & 3 lights together, see cut and paste message from manual:
"The Diagnostic Lights flash as follows:
...
2. The High Limit switch. This sensor will
sense if the unit reaches temperatures that are
too high for normal operation. If this happens
the Auger will quit feeding and the #2 and #3
LED lights will flash simultaneously. (See
Figure 2 on Page 5 and point 4 on page 16)" from page 7 of the manual I downloaded for St. Croix Afton Bay Operation and Maintenance.

The hopper is full of fuel. I spent a good 2-3 hours cleaning the stoves hard to reach areas. cleared the vacuum tube. By passed the vacuum switch with a jumper (which should work if the switch was bad because it is a normally open switch) The voltage to the switch is correct, 5 V one side only at the control board pins.
Because the stove goes into safety shut down in 45 to 75 seconds, I don't think the proof of fire switch should have been polled yet.

I have rechecked the high limit switch and I think it is a problem between the switch and the control board. The high limit switch is a normally closed switch and at the control board only one pin to the switch should have voltage (line voltage). At the switch only one wire has voltage (120V) when they are not connected to the switch. But when connected the circuit completes. I hit the reset button on the switch but it won't reset to a closed position. So I have a bad high limit switch, one problem identified. What I don't understand is why I can't get the stove to light when I try to bypass the switch. Because it is a normally closed switch I thought if I disconnect it the board would sense it as a operational closed switch - didn't work, same error message. Then I tried to light to light it while holding the reset button during startup (which does close the switch, I kept a voltmeter on it) still didn't work.
I'm ordering a new switch, I wonder if there is another problem.