Ok our heater was triggering off a red light and it blinks four times which meant limit switch we replaced all the limit switch cleaned the flame sensor off and then it still did it so he got to the coil and cleaned it also cleaned the blower and still it's doing the same thing. This is what it does the igniter gets hot then u hear the click all the flames light up then immediately the blower kicks on and not long after that the flames go out. We have it turned up to 80 and the house won't heat up past 60 please help me!

Model number would help. Does the furnace have a draft inducer fan, is it activated when burner lights?

The model number is BGU7512A and I don't know if it has a draft inducer fan I think so but I'm not 100% positive.