furnace return air duct

hi. i found a furnace in a ranch home full basement. The only return air
duct was running 3 ft off of the furnace with a filter sitting on top of
the open duct work. this is a up flow forced air furnace. there were no
return air ducts any were else. I said that a heating and cooling co.
should advise if this is proper. any comment?

Return-air cannot be taken from the same room as a gas-fired furnace. This is a serious safety hazard that needs to be corrected.

Thanks I knew that return air was not sapose to be drawn from a basement
are. also that system must have very poor circulation. also a pressure
issue on the main level.

Colorado requires the return air to be at least 10 ft away from the unite in a open basement. If the furnace is in its own room you can not have a return in it.

Isn’t that 10 feet from or from a room with insufficent volume for combustion air?

There should never be insufficient combustion air. That would be a completely different problem. Return should never be within 10 ft of the unite if it is in a Open basement. and should never be in a enclosed furnace room even if it has enough combustion air. Furnaces with a sealed combustion chamber has another set of rules. General rule of thumb if it looks out of the ordinary or just not refer it to a licensed professional.