Furnace problems

[04fxsts]

2015 30.1 ACE furnace making noise when not running. This is strange, opened the back door next to where MH is sitting winterized and plugged in as we have always done. I hear a noise that at first sounded like the water pump running. It is 3 AM and 24 degrees F so I just shut off the power to check later. Water pump was not on and now I hear the noise is coming from the furnace bay. The furnace was not on so turned on and it cycles coming on for a few seconds each time and then shutting off. It has always done this but then comes on and then would always run fine.
When I shut the heat off at the thermostat the blower goes off then the noise starts, sounds like ignitor running. Now I am thinking with all the rain we have had it is the circuit board being wet, fairly common problem I understand.
Now the next problem, I took the screws out of the panel to get to the furnace. I can't pull it off the side of MH, it seems the exhaust pipe is stuck inside. I assume the pipe comes out with the cover panel. If correct how is the best way to get it loose? Thanks, Jim.

[Grumpy Grampa]

Yes, it’s a challenge, you have to turn and pull, wiggle.

[CHS]

They use a sealer around the pipe for safety when it's installed, like previously said, you have to pull and wiggle.

Thats said. Just curious, Do you have any type of pipe, or underneath heating system to keep things from freezing. Could that be on? They sometimes turn on automatically at a preset temperature.

[16ACE27]

The pipe has it's own screws. Remove them and remove the pipe before removing the panel.