Magnum Baby Countryside heat Level 2 blinking error.

Hello
This 17 year old stove did not run and failed with the 2 light error.
There are a few causes here and this stove has not seen service in over two years.
The exhaust blower was working but the stove had a lot of ash. Therefore we cleaned out all the ash and using a compressor, blew out ash around the heat exchanger tubes in the top of the firebox, blew out the upside down u in the back of the firebox, and the air wash slot below the inside of the fire door. Then the original 17 year old door and ash pan gaskets were replaced. Many of the holes in the bottom of the burnpot were clogged so they were unplugged and the firepot was thoroughly cleaned. The exhaust blower was upgraded 8 years ago to the 105 CFM so there was plenty being generated to the 4” diameter pro venting.
This got the stove working but it still failed after 2 hours with the 2 error still!
The only original part was the negative pressure vacuum switch which has a very sensitive trip point of 0.07 WC = Water Column. Also the vacuum hose takes the air for measurement in the lower right side of the fire box which is why the very low trip point is used. Therefore since the micro switch must be working because the stove runs for 2 hours, the best way to test this switch is to test the bladder for a leak. See test below
A good way to test any pellet stove vacuum switch.
https://m.youtube.com/shorts/UntlGetlad0
Since this test did fail and we replaced the vacuum switch, the stove has been running well ever since.