New PF 100 user with questions

Hello all.

I recently installed a Harman PF 100 and scrapped my oil burner. So far I'm happy with the heat output, but we haven't had any real cold weather yet.

I noticed that when there is just a little demand for heat, the PF 100 will continually feed pellets but takes a real long time (if ever) to get the distribution blower to come on. (low set point 100 degrees per the manual). It's acting like a pilot light, but I'd rather not burn any pellets if the dist. blower isn't going to come on in say 10 minutes tops.

When there is a demand for heat the thing goes like a jet engine and the distr. blower comes on quickly.

Any ideas?

Here are some particulars...

feed rate to 3 burning Energex Premium grade. The manual says 4, but I noticed a few un-burned pellets.
7' of vent pipe 1-90 deg., 1-45 deg.
homemade outside air: 3" galv. exiting furnace to 3"alum. flex-duct to 4" galv. to 4"diameter screen vent.
I will probably change-out the 3" alum. flex to galv. pipe because it probably creates too much resistance in the 20' run.

Other things that I've noticed...
t-stat not even close
the combustion blower goes on a long time. I thought the outside air pipe would fix that.
the little flapper in the door sometimes flaps like crazy. I think if I switch to a smooth wall outside air pipe this will be eliminated.

Thanks for the feedback. I will do the t-stat trick too. Even with the feed set at 3, I find some unburned pellets in the ash. I think it happens upon ignition.

I installed per the manual at 11" up and centered. Maybe 3 is too low a setting and I need to throw more pellets into the burn pot to hit the high limit??? I need to investigate when these un-burned pellets (about a handful every 3 bags) are coming. I might be making the wrong assumption that feedrate at 4 was causing it.

This forum is a great resource. Thanks for the responses. I'm wondering if a PF 100 owner has greated a FAQ or Wiki...

How often do PF 100 owners do a more thorough cleaning? I've only done a daily burnpot scraping and wonder if things at the bottom of the burnpot are getting crusty. It's impossible to see in there. I will invest in a mirror.

The daily burnpot scraping probably means I have nothing better to do. ;^> I don't think most PF 100 owners are doing that.