How to check pressure in coal stoves

Hi I was wondering if anyone knew how you would check the pressure inside coal or pellet stoves ect to see if there’s a leak. I have a hitzer stoker which I have a manometer on so I shouldn’t need to check that with much else unless my reading is way off but specifically on a Harman dvc 500 how would you check the pressure which is negative I believe? Thanks

The DVC is a unique setup. I would start with the manual.

I’ve read the manual over a few times. But didn’t see anything related to that I’ve replaced every part and gasket I can think I currently have every motor and fan out of the stove getting serviced at a electric motor shop to be safe. Removed the pusher block and cleaned as well as the pusher fork. All new glass door gaskets handles, fss tube, control board esp and tcp sensor. I have the grates and the fire box under the grates removed and installing a new gasket there as well… my next step is to get a tech here and the closest one is over an hour a way and he’s never worked on a dvc

If you are still looking to get a draft reading on the DVC - the simplest way is to tee a gauge into the FSS line.
Selecting ash out pins Magnehelic gauge.
Getting an eye on draft readings would tell you a lot about whats going on with the controls.