Go here for troubleshooting steps for Blend Air systems :
On some digital t-stats, there is an internal anticipator, but on most there is not.
Read the t-stat manual or look it up online.
Make sure burner and burner orifice are clear and not clogged with spider/web.
Could be faulty control board, would have to test board to know.
As long as the board shows 24vac across W and C, then the burner and blower motor should be going along with booster motor.
When there is no 24vac at W and C, all should be off.
Might need to find a reputable company with knowledgeable and trained hvac techs.
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?