I'm trying to find out if they are legal, before I have someone service it... it leaves black soot all over my walls. We are going on our third year renting here and repainting every year is getting old... it is our primary source of heat... my landlord told me the soot is from pet dander..

It sounds like the regulator isn't working correctly,the gas isn't burning properly and the soot is a by product of unburned gas, that makes the soot.

Typical on LP ranges and other gas heater units.If you have it serviced,make sure they adjust or replace the ? Adjuster ? Regulator?, whatever makes the gas burn properly and completely.

You shouldn't have any soot from an unvented unit.