M55 damper setting ?

My Omega is very similar. Tygon tubing should work fine as its not going to be there long. I used standard vinyl tubing. I also used a barbed fitting in the hose(made by Clippard #C44). You could use a piece of brass tubing or brake line. This will help keep it centered in/on the hole.

I used a basketball air needle pushed into the end of some urethane tubing. I found that the stove was too hot to just push the tubing up against it because it would melt. The hole above my door is threaded. I have to remove a screw to do my magnahelic reading. So is there a screw in the hole in your stove?
Flynfrfun

My Omega's check point is low on the unit and probably a cooler location. If its that hot of an area? You could use the same tubing as whats on the vacuum switch. Silicon has a higher heat rating.

Some of the early Enviro's didn't have the check point hole. We used to use a standard vacuum tee and short piece of tubing in the vacuum switch line close to the vacuum switch. Nice because you didn't need to hold the hose/tubing! Once done checking we would put a cap over the tee. You probably could use a longer hose and use some type of plug. Neatly tuck the hose in the stove body for future use. Just throwing ideas around!

Yeah, the M55's hole is above the right top corner of the door. Also, they want the stove running on heat level 5 for 1/2 to 1hr, so it's pretty hot. If I were you I'd tap the hole and put a screw in it. It might not affect how the stove runs, but it would make me feel better. If you don't have a tap and die set, just find a screw that you can thread into it.