To replace a defective shut-off valve, first
remove vent pipe’s vent “cap” outside the building or home. Place a regular cap
on temporarily. Remove fill fitting from fill pipe outside as well. Then, take
the hose from a soot vacuum and place it over the fill pipe. Duct tape hose to
fill pipe for a good, airtight seal and turn on the vacuum.
The vacuum created will indeed hold that oil
in suspension inside the tank while you can relax and remove the old valve
without losing a lot of oil and making a stinking mess, or having to do it
“on the fly” as oil pours out!