Note taken. I think there is a fine line between getting enough air across not to form a bubble and getting too much air where the fin ignitors won't light a flame because too much air is basically blowing the fire out, my opinion. What's your take on my aquastat issue ?

I'll try the 1-off 2-on 3-off dip setting and see what that does. Like I stated before I don't think I've gone over 7 minutes before I see flames. As a matter of fact last evening I put a bag of pellets in where some of them were like saw dust. Hey if your like me you want to see how this beast ig going to react, that's how you learn. Anyway it wasn't 2 minutes before I had flames. Yep, it was some of those "Sawdust" pellets that probably ignited quicker. I also set the max temp to 150 and min temp to 120, feed rate was 4 (If I set higher I get 3/4 burnt pellets falling in the ash box). After about 30 minutes the boiler temp was 180% and the flames were still wraping around all 3 heat exchangers. So like I said I think it's either the control board or the aquastat sensor. BTW - before I got onto any forums I was playing around with the flame/draft by using a restriction on the air inlet and a damper on the exhaust. The best flame I've seen was nice and blue for about 1.5 inches and then a nice bright yellow (almost white), from bottom to top, and that was with the inlet restricted to about 75 percent and the damper about 3/4 closed. The 1st heat exchanger accumulates the ash dust that is almost white. My take on this is just like a spark plug on car engine (my hobby is muscle cars / drag racing), the air/fuel ration has to be set right for a good combustion. Harmon should be aware of this and build in another sensor in the firebox to set feed rate, air inlet, and exhaust blower to get the proper mix. That's my opinion for what it's worth.

Thanks for replying. The control board I am currently using is the 6143. I was really worried about the smoke issues that I read about but mine at the most is 7 minutes from a cold start to the time it ignites, butn pot might be 2/3 full with the first 3 dip swithes set on. No pressure ignitor, just the 15 fin ignitor. When on auto, isn't the flame suppose to go out after it reaches the max temp ?

Well after a bit of research and paying for my last fillup of fuel oil I broke down and bought a used PB105. Got it hooked into a series with oil boiler, the PB105 is a nice boiler (but working in Engineering and Infomation Technolgy field for the last 35+ years I can say it could be better), anyway it was the right price. It's a older model (MFG date 12/2006) but it has a newer ignitor, the burn pot looks great, and I think I can make it work for me. The first few times using it (burning pellets) the thing wouldn't heat over 140%, I kept saying to myself "this isn't right". So I cured that by getting a new red wired ESP (and yes I had to splice it to make it reach). I have the the 1st 3 dip switches set to on and of course the #5 dip set on also ((red wired ESP). It's got the newer control board but I don't know if it's working properly or not, can those be reset in anyway (firmware or mapping) ? Being new at this I don't know how these things are suppose to act. Anyway, this was a DIY install and have some questions if anyone don't mide sharing there knowledge. When the max temp is set to 160% (with or without the OAT sensor, I've tried both ways), does the control board adjust the feed rate ? Seems like if I have the feed rate at 1 the boiler temp stays around 140%, 2 at 155%, 3 at 165-175%, 4 is beyond 180%. I thought no matter what you have the feed rate set at in auto mode and you were using the OAT and Aquastat sensors (by the way same sensors) your suppose to set the min and max temps and that is what the boiler temps would adjust to depending on the outside temp ? Not mine, if I have the feed rate at 3 and the max temp at 155 the temp will reach 175 and never go out (in auto mode I thought it wa suppose to go out?) Enough for now, gotta say it's going to be a challenge but I think I'll get at to work for me with some of your help. Thanks.