I just serviced a Pensotti R series...I think it's an R series. It had the man on the front case and it's on the older side. The front casing pulls off and the two bolt access door is on the front of the boiler.
I cleaned out the flue passages and removed the smoke pipe from the back of the boiler and vacuumed that out. I have a positive draft coming from the viewing hole. Is there another access to clean out the boiler that I missed. The breech draft is -.03.