Hey. New to the forum and to wood burning. I installed a HotBlast 1557 in the basement of our old farmhouse. 24 feet of stainless steal lined chimney. I drilled a 1 inch hole just under the smoke shelf in the back and welded in a pipe for secondary burn air. The pipe comes in the back and t’s off to 2 pipes that go out to the outer edge of the stove up to the front then in a little then back down the length of the firebox all just under the smoke shelf the pipes as they make 2nd run down the stove have 7/32 holes every inch to let air to the top of the fire after it’s preheated . I am having trouble keeping the secondary burn going. I get the fire roaring then shut the bottom ash door leaving the spinner almost closed. Damper on top full open. The secondary burn starts and will go until the fire underneath dies from lack of air. Then the secondary dies and I’m left with a smoky smoldering fire. If I open up the spinner some I can get the secondary’s to stay lit but goes through wood. Full load of dry walnut gone in 5 to 6 hours. I do have firebrick on top of the smoke shelf and some added on the back. Any tips on settings to keep the secondary burn going while dialing back the main burn. I will add pics in the am.