Question on Stelrad NC-2 wood/coal boiler

[Hawnsz]

Total noob to the forums here, been a lurker for a while. Haha
I have a simple question on my wood boiler door, as it has a sliding vent and can't find any information on it's purpose. I've always kept it shut as I want it's hydro damper to control airflow but never figured out if it's just more air inlet or maybe for a better draft?

Any information would be greatly appreciated!

Can't find any documentation on this guy haha

Stelrad NC-2 WOOD/COAL boiler

 

[3fordasho]

I don't know for sure but it could serve a couple purposes- when starting a fire from scratch it may help to get it started by having that open, then close when the fire is established. It could also be used prior to a reload on a partially burned load, the extra air would tend to heat things up raising the draft and perhaps reducing the smoke spillage when you open the loading door. For most of a normal burn it would be closed as you are doing.