Hastings Shutting Down #3 light

Hello - looking for a little advice/help. About 4 times over the last 3 weeks I have come up/woken up to my stove being off and the #3 light blinking. A little history: Stove is a St Croix hastings, 7 years old. I clean it every two weeks and do a full breakdown each year. Last year my combustion fan went. I replaced it with a new one that kicked the bucket in December. When I replaced it in December, I was noticing some creosote build up so since the stove keeps shutting down and I was getting build up, I decided to open the damper a bit for more air....it seemed to help with the creosote but not the shutting down.

When I checked the burn pot today there were unburnt pellets....so I am thinking the stove is shutting down due to a POF issue?

Any help is appreciated....the #3 light seems to be caused from a few things in the posts I have read. Just looking for a starting point to troubleshoot.
Thanks

Thanks for the reply bioburner. I have it hooked up to a thermostat and it usually goes for a good 20 minutes a couple of times a day. Just to be sure though, I will start doing it each night to see if it helps. Also, I cleaned the stove Saturday morning and it was off when I got home from work, so I don't think it is a cleaning issue.

Thanks..I will check the POF switch tomorrow. Much appreciated

So I have been playing around with this....it is taking a few days for the stove to shut down. I checked the POF switch and it didn't have any build up, but I gave it a good brushing. I also played with the combustion fan voltage. I have been thinking maybe the POF switch is faulty????

Should I try replacing it?

Thanks....I found one for 46$ so I think it is worth a shot. If this doesn't work....I am throwing my hands up. Appreciate the help

Thanks Heet Seeker for that link! Going to buy it anyway just to have one on hand.

I did read about the combustion air so I did lower it back to what I originally had it set at yesterday when I got home. I guess I will know in a day or two. I think it makes the most sense since that is what I changed originally when this started happening (problem is you start making so many adjustements, you forgot what you touch. Think i need to start writing down what I troubleshoot next time a problem starts). If this works, I will then need to work on the creosote isssue...although I am making sure I do 2 good high burns a day now for at least 20 minutes each.

I will let you know in a couple of days if it is the combustion air. Appreciate all your advice and help. This forum has the most helpful people I have ever come across! So glad it is here.

So far no shut downs.....sounds like it may have been too much air on the damper. Thanks everyone.