Just changed the ignitor and the flame sensor on my goodman furnace yesterday... today I went and put the thermostat to 85... it ran normal for over an hour and a half so I decided to lower the temp to 80... the room temp was almost 50 on the thermostat... but once I lowered it to 80, the flames went out and the blower stopped... now what, please help... the LED is solid red... thanks

Sounds like the furnace is doing its job. The tstat I`m sure has a name brand and model number to tell us what you are working on. 85 or even 80 is awfull warm for most any size house. Put it down to a normal 70 or 72, see if it works right then,not knowing if you have a digital or analog temperature read out on the tstat,make it hard to give you any help