I have a lennox g24m3-75. I have been reviewing several posts and after watching my lights blinking and using the diagnosis codes, I have seen that I am receiving multiple codes. During what appears to be normal operation, I have gotten a primary/secondary switch open, a pressure switch open, and a roll out switch open. Most times when it shuts the flame off prematurely I get a low flame code. Usually the next time it tries to light after that I get a watchguard code. I have gotten a "flame sensed without valve energizing" once after a premature shut off. Can you help me at all? Basically I have been having problems with it maintaining the temperature in the house. Sometimes we'll get up in the morning an it's 8 degrees under the regulated temp. Sometimes we have to reset the furnace, so that it will try to kick on again. Can you help me at all?

When was the last time your furnace was serviced by a HVAC company?

You are having way to many problems. Usually one problem causes a indicator to light and you stated you have many. It might be best to have a Professional do a ON SITE inspection of your unit and get to the main problem before the real cold weather gets here.