Mt. Vernon Quadrafire Vacuum Switch Error Help! Please!

[Babygotbuttbbq]

Ok....Getting a vacuum switch error. I have done the following:
1. Cleaned entire unit top to bottom including blower and exhaust
2. Check and blew out vacuum hose
3. Jumped the switch...unit worked.
4. Replaced the switch with a new switch.....no workie
5. Said a few really bad words.
6. Checked for leaks...none apparent.

Any and all suggestions would greatly be appreciated. Very frustrated!!

 

[Bioburner]

How old of stove? Checked the door gaskets(dollar bill test)?

 

[Babygotbuttbbq]

How old of stove? Checked the door gaskets(dollar bill test)?

Stove is 3 years old. tight as a drum around the door and ash pan.

 

[Babygotbuttbbq]

Got it. Top of chimney cap is a ninety degree. there was a blockage in it.

 

[Bioburner]

Not cleaned all the wayyyy out.