Should my view port / sight port be sealed?

wf

Recently moved into a 1940's cape with single pipe steam heat system.  Should the view port / sight port on the furnace? boiler? be sealed?  Every now and then I smell burning oil when the system turns on.

Charlie from wmass

The boiler may need a cleaning

Also the chimney may need cleaned.

toilburn

view port

Unless it is a pressure-fired boiller it does not need to be sealed. You have a draft problem or a partially plugged boiler.